eIF3a is a N ⁶-methyladenosine (m⁶A) reader that regulates mRNA translation by recognizing m⁶A modifications of these mRNAs. It has been suggested that eIF3a may play an important role in regulating translation initiation via m⁶A during infection when canonical cap-dependent initiation is inhibited. However, the death of animal model studies impedes our understanding of the functional significance of eIF3a in immunity and regulation in vivo. In this study, we investigated the in vivo function of eIF3a using eIF3a knockout and knockdown mouse models and found that eIF3a deficiency resulted in splenic tissue structural disruption and multi-organ damage, which contributed to severe sepsis induced by Lipopolysaccharide (LPS). Ectopic eIF3a overexpression in the eIF3a knockdown mice rescued mice from LPS-induced severe sepsis. We further showed that eIF3a maintains a functional and healthy immune system by regulating B cell function and quantity through m⁶A modification of mRNAs. These findings unveil a novel mechanism underlying sepsis, implicating the pivotal role of B cells in this complex disease process regulated by eIF3a. Furthermore, eIF3a may be used to develop a potential strategy for treating sepsis.

Objective:To evaluate the epidemiological characteristics and influencing factors of out-of-hospital sudden cardiac death (SCD) in Hangzhou from 2016 to 2019.Methods:SCD events recorded by Hangzhou Emergency Center from January 1, 2016 to December 31, 2019 were reviewed. Demographic and mortality data were recorded, and the distribution patterns of SCD events in terms of date, time, and population with different characteristics were observed. Time series analysis method and a distributed lag nonlinear model based on quasi-Poisson distribution were used to explore the possible nonlinear association between ambient temperature and SCD incidence.Results:A total of 4 744 out-of-hospital sudden death events were recorded by Hangzhou Emergency Center from January 1, 2016 to December 31, 2019. After excluding non-SCD events and observed events with missing items, 3 743 SCD events were finally included in the study. The survey results showed that the incidence of out-of-hospital SCD in Hangzhou was 96.5 cases per 100 000 person-years. Most of the people who experienced SCD were aged ≥60 years. The incidence in males (2 462 cases, 66%) was significantly higher than that in females (1 281 cases, 34%), and the proportion of events occurring during the day (2 737 cases, 73%) was significantly higher than that at night (1 006 cases, 27%), mainly occurring between 7: 00 and 9: 00. High temperature was associated with an increased risk of SCD. When the average daily temperature was higher than 25.5 ℃, the risk of SCD increased with the further increase of average daily temperature.Conclusions:SCD events mainly occur in the elderly population aged ≥60 years, with a significantly higher incidence in males than in females, and more frequently during the day than at night, mainly between 7: 00 and 9: 00 in the morning. High temperature is closely related to the risk of SCD. It is particularly important to carry out targeted SCD screening and prevention for different populations and implement appropriate prevention strategies for high-risk groups of SCD in high-temperature weather.

Objective:To investigate the effect of DEAD-box helicase (DDX) 21 on myocardial ischemia-reperfusion (I/R) injury and its potential mechanisms.Methods:In vivo, adult male Bama pigs and C57BL/6J mice were used to establish a myocardial I/R injury model by ligating the left anterior descending coronary artery, with sham-operated groups set as controls. The expression of DDX21 in myocardium after I/R injury was assessed by quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence staining. Following the establishment of the myocardial I/R injury model in mice, AAV9 vectors with cardiac-specific expression were injected in situ into the peri-infarct region (The I/R+DDX21 group, I/R+negative control (NC) group, I/R+sh-NC group and I/R+sh-DDX21 group were injected with AAV9:cTnT-DDX21, AAV9:cTnT-NC, AAV9:cTnT-sh-NC and AAV9:cTnT-sh-DDX21, respectively). Additionally, the I/R+A-485 group received intraperitoneal injections of the cAMP response element-binding protein (CREB) binding protein inhibitor A-485, while the I/R+PBS group was injected with an equivalent volume of phosphate-buffered saline (PBS) as the control. Echocardiography was performed on postoperative days 1 and 28 to evaluate cardiac function (left ventricular ejection fraction and fractional shortening). At 28 days post-surgery, mice were euthanized and heart tissues were harvested for histological sectioning. Myocardial fibrosis was evaluated using Masson′s trichrome staining. In vitro, primary cardiomyocytes were isolated from neonatal day 1 C57BL/6J mice using enzymatic digestion method. Cardiomyocytes were transfected with plasmids or small interfering RNA (siRNA). The cardiomyocytes transfected with DDX21-siRNA were assigned to the siDDX21 group, those transfected with the DDX21 plasmid were assigned to the DDX21 group, and those transfected with the corresponding empty plasmid or siRNA were assigned to the NC group. Additionally, cardiomyocytes were treated with A-485 (A-485 group) or PBS (PBS group). An oxygen-glucose deprivation/reoxygenation (OGD/R) model was used to simulate cellular injury. Transcriptome sequencing was performed to identify downstream mechanisms of DDX21. Differential gene expression analysis was conducted using software such as DESeq2, and alternative splicing events in the mRNA transcriptome were analyzed using rMATS software. Mitochondrial superoxide, mitochondrial membrane potential, ATP content, and mitochondrial respiratory chain complex enzyme activity in cardiomyocytes were detected using immunofluorescence staining and commercial assay kits. The oxidative phosphorylation level of the cells was assessed by the Seahorse extracellular flux analyzer. Acetylated DDX21 levels were measured using co-immunoprecipitation and Western blot assays.Results:The expression levels of DDX21 in myocardium from the Bama pigs and mice in the I/R injury model were significantly higher than those in the sham group (all P<0.001). Echocardiographic results showed that at 28 days post-surgery, compared to the I/R+NC group, the I/R+DDX21 group exhibited higher left ventricular ejection fraction and fractional shortening, while the I/R+sh-DDX21 group showed lower values; Masson staining results demonstrated that, compared to the I/R+NC group, the myocardial fibrosis area in the I/R+DDX21 group was significantly reduced, whereas it was significantly increased in the I/R+sh-DDX21 group (all P<0.001). Transcriptomic sequencing results suggested that DDX21 may influence myocardial injury by regulating mitochondrial metabolic activity. In vitro, compared to the OGD/R+NC group, the OGD/R+DDX21 group exhibited lower mitochondrial superoxide levels, higher polymer/monomer ratio, maximal oxygen consumption, reserve capacity, and ATP content. In contrast, the OGD/R+siDDX21 group showed the opposite results, with reduced activity of mitochondrial respiratory chain complex V (all P<0.05). Mechanistically, rMATS software and other analyses indicated that knockdown of DDX21 affected the alternative 3′ splicing sites of ATP5J precursor mRNA, inhibiting the splicing of certain exonic sequences. Overexpression of DDX21 upregulated both mRNA and protein levels of ATP5J. Co-immunoprecipitation experiments showed that, compared to the PBS group, acetylated DDX21 levels were reduced in the A-485 group. Further in vivo experiments showed that, compared to the I/R+PBS group, the I/R+A-485 group exhibited higher left ventricular ejection fraction and fractional shortening, and a lower proportion of left ventricular fibrosis (all P<0.001). Conclusions:DDX21 improves cardiomyocyte energy metabolism and alleviates I/R injury by regulating the alternative splicing of ATP5J. A-485 holds potential as a novel small molecule candidate for the treatment of myocardial injury.

BackgroundChildhood represents a critical stage for cognitive development. Accurate assessment of children's cognitive abilities and understanding their developmental characteristics are essential for promoting healthy growth. However， traditional cognitive assessment methods typically rely on manual administration， presenting limitations such as low efficiency and insufficient engagement. These methods struggle to meet the assessment needs of children and are difficult to scale up for large-scale applications. ObjectiveTo develop a digital cognitive assessment tool for children， so as to provide a more convenient approach for evaluating children's cognitive functions. MethodsBased on classic psychological paradigms （Stroop Task， N-back， digit span， spatial orientation， and face-name matching）， a digital cognitive assessment tool was developed. This tool includes five tasks including color matching， shape matching， greening the home， great collector， and face-name matching， designed to assess core cognitive functions such as inhibitory control， working memory， short-term memory， spatial orientation， and semantic processing， respectively. From August 2024 to March 2025， a total of 750 students aged 9–12 yeas old from a primary school in Chengdu were enrolled and assessed using the digital cognitive assessment tool. Three months later， 40 children were randomly selected for retesting using both the digital tool and its corresponding standardized psychological paradigms. Pearson correlation analysis was conducted to examine the correlation between the pre-test and retest scores of the digital cognitive assessment tool， as well as the correlation between the digital cognitive task scores and the corresponding psychological paradigm assessment results， in order to evaluate the reliability and validity of the digital cognitive assessment tool. Additionally， differences in scores across the cognitive tasks were compared among children of different age groups and genders. ResultsA total of 699 valid samples were included. The younger age group consisted of children aged 9–10 years old （n=460）， while the older age group comprised those aged 11–12 years old （n=239）. There were 356 boys （50.93%） and 343 girls （49.07%）. In the reliability analysis， the Pearson correlation coefficients between the pre-test and retest scores of each assessment task ranged from 0.732 to 0.970 （P<0.01）， indicating statistically significant results. In the validity analysis， the Pearson correlation coefficients between each task and its corresponding standard cognitive test ranged from 0.679 to 0.988 （P<0.01）. In the color-matching task， both the main effects of age and gender were statistically significant （F=31.071， 21.198， P<0.01）. In the shape-matching task， the main effects of age， gender， and their interaction were all statistically significant （F=20.933， 5.926， 4.318， P<0.05 or 0.01）. In the greening the home task， the main effect of age was significant （F=5.243， P=0.023）. In the great collector task， the main effect of age was significant （F=33.697， P<0.01）. In the face-name matching task， only the main effect of gender was significant （F=27.016， P<0.01）. Further analysis showed that within the female group， older group scored significantly higher than younger group in five tasks（P<0.05 or 0.01）. Within the male group， younger group scored lower than older group in both the color-matching and great collector tasks （P<0.05 or 0.01）. Within the younger group， boys scored significantly higher than girls in color-matching and shape-matching tasks （P<0.01）. In the older group， girls scored significantly higher than boys in face-name matching task （P<0.01）. ConclusionThe digital cognitive assessment tool developed in this study demonstrates good reliability and validity. The development of cognitive functions in children aged 9–12 years old showed significant differences in age and gender， with specific developmental trajectories across different cognitive dimensions. At younger ages， boys outperformed girls in inhibitory control and working memory tasks， though this advantage diminished with age. At older ages， girls exhibited superior performance in semantic processing compared with boys.

Objective:To investigate the biological role and molecular mechanism of checkpoint kinase 1 (CHK1) in delaying cardiac aging in mice.Methods:In vitro, a senescence model of H9C2 cells (a cardiomyocyte line) was induced using H 2O 2. A control group (without H 2O 2 treatment) and three H 2O 2-treated groups (at concentrations of 10, 30, and 50 μmol/L) were set up. The CCK-8 assay was used to evaluate the proliferative activity of cells in each group; Western blot analysis was employed to detect the expression level of CHK1; and quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the messenger RNA (mRNA) expression levels of P16 and interleukin-1β (IL-1β). In vivo, C57BL/6 wild-type mice aged 2 months ( n=15) and 24 months ( n=40), as well as myocardial-specific CHK1-overexpressing (CHK1-TG) mice aged 2 months ( n=15) and 24 months ( n=40), were selected. The mice were divided into four groups based on age and genotype: 2-month-old wild-type (WT-2M), 24-month-old wild-type (WT-24M), 2-month-old CHK1-TG (CHK1-TG-2M), and 24-month-old CHK1-TG (CHK1-TG-24M). Echocardiography was used to evaluate cardiac function of mice in the WT-24M and CHK1-TG-24M groups. Western blot analysis was conducted to measure the protein expression levels of CHK1, total Ras-related protein 1 (Rap1), NADPH oxidase 4 (Nox4), and Rap1-guanosine triphosphate (Rap1-GTP, the active form of Rap1) in the cardiac tissue of mice in each group. qRT-PCR was used to detect the messenger RNA (mRNA) expression levels of CHK1, collagen type Ⅰ (Coll1), matrix metalloproteinase-2 (Mmp2), alpha-smooth muscle actin (α-SMA), P53, P21, P16, thioredoxin 1 (Trx1), thioredoxin reductase (TrxR), glutathione recluctase (GR), Rap1, and Nox4. Immunofluorescence staining was employed to determine the protein expression levels of P53, P21, and P16, as well as the proportion of histone H2AX phosphorylation-positive cells. Dihydroethidium (DHE) staining was used to detect the relative intensity of DHE. Wheat germ agglutinin staining, HE staining, Masson staining and Sirius red staining were applied to measure the cross-sectional area of cardiomyocytes, cardiac morphology, and myocardial fibrosis area. Mice in the WT-24M and CHK1-TG-24M groups were intraperitoneally injected with the Rap1 activity inhibitor GGTI298 (25 μmol/kg). After injection, the oxidative stress damage in the cardiac tissue of the mice was detected, along with the mRNA expression levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P16, P21, and P53). Results:A concentration of 30 μmol/L was determined as the optimal concentration for establishing an H 2O 2-induced senescence model of myocardial cells in vitro. The expression level of CHK1 in H9C2 cells of the 30 μmol/L H 2O 2 group was lower than that in the control group ( P<0.05). Echocardiographic examination showed that the left ventricular ejection fraction ((61.08±1.13)% vs. (52.55±2.02)%) and fractional shortening ((31.80±1.27)% vs. (25.18±1.59)%) of mice in the CHK1-TG-24M group were higher than those in the WT-24M group (both P<0.05). qRT-PCR and Western blot analysis revealed that, compared with the WT-24M group, mice in CHK1-TG-24M group had higher expression levels of CHK1 and its mRNA, lower expression levels of Nox4 and its mRNA, and higher expression level of Rap1-guanosine triphosphate (Rap1-GTP) (all P<0.05). However, there were no statistically significant differences in the total expression level of Rap1 and its mRNA between the two groups (both P>0.05). In addition, the mRNA expression levels of Coll1, Mmp2, and α-SMA in myocardial tissue of mice in the CHK1-TG-24M group were lower than those in the WT-24M group (all P<0.05). Immunofluorescence staining results showed that the expression levels of P53, P21, and P16 proteins, as well as the proportion of phosphorylated histone H2AX-positive cells in myocardial tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). qRT-PCR further confirmed that the mRNA expression levels of the above-mentioned proteins in cardiac tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). DHE staining results indicated that the relative intensity of DHE in cardiac tissue of mice in the CHK1-TG-24M group was lower than that in the WT-24M group ( P<0.05). Meanwhile, the left ventricular internal diameter, cross-sectional area of cardiomyocytes, and myocardial fibrosis area of mice in the CHK1-TG-24M group were all smaller than those in the WT-24M group (all P<0.05). Furthermore, the degree of DNA damage in cardiac tissue as well as the mRNA levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P53, P21, P16) in mice of the WT-24M+GGTI298 group were higher than those in the WT-24M group and the CHK1-TG-24M+GGTI298 group (all P<0.05). Conclusion:CHK1 alleviates oxidative stress-induced damage in mouse cardiomyocytes by activating the Rap1/Nox4 signaling pathway, thereby delaying cardiac aging in mice.

Objective:To evaluate the epidemiological characteristics and influencing factors of out-of-hospital sudden cardiac death (SCD) in Hangzhou from 2016 to 2019.Methods:SCD events recorded by Hangzhou Emergency Center from January 1, 2016 to December 31, 2019 were reviewed. Demographic and mortality data were recorded, and the distribution patterns of SCD events in terms of date, time, and population with different characteristics were observed. Time series analysis method and a distributed lag nonlinear model based on quasi-Poisson distribution were used to explore the possible nonlinear association between ambient temperature and SCD incidence.Results:A total of 4 744 out-of-hospital sudden death events were recorded by Hangzhou Emergency Center from January 1, 2016 to December 31, 2019. After excluding non-SCD events and observed events with missing items, 3 743 SCD events were finally included in the study. The survey results showed that the incidence of out-of-hospital SCD in Hangzhou was 96.5 cases per 100 000 person-years. Most of the people who experienced SCD were aged ≥60 years. The incidence in males (2 462 cases, 66%) was significantly higher than that in females (1 281 cases, 34%), and the proportion of events occurring during the day (2 737 cases, 73%) was significantly higher than that at night (1 006 cases, 27%), mainly occurring between 7: 00 and 9: 00. High temperature was associated with an increased risk of SCD. When the average daily temperature was higher than 25.5 ℃, the risk of SCD increased with the further increase of average daily temperature.Conclusions:SCD events mainly occur in the elderly population aged ≥60 years, with a significantly higher incidence in males than in females, and more frequently during the day than at night, mainly between 7: 00 and 9: 00 in the morning. High temperature is closely related to the risk of SCD. It is particularly important to carry out targeted SCD screening and prevention for different populations and implement appropriate prevention strategies for high-risk groups of SCD in high-temperature weather.

Objective:To investigate the effect of DEAD-box helicase (DDX) 21 on myocardial ischemia-reperfusion (I/R) injury and its potential mechanisms.Methods:In vivo, adult male Bama pigs and C57BL/6J mice were used to establish a myocardial I/R injury model by ligating the left anterior descending coronary artery, with sham-operated groups set as controls. The expression of DDX21 in myocardium after I/R injury was assessed by quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence staining. Following the establishment of the myocardial I/R injury model in mice, AAV9 vectors with cardiac-specific expression were injected in situ into the peri-infarct region (The I/R+DDX21 group, I/R+negative control (NC) group, I/R+sh-NC group and I/R+sh-DDX21 group were injected with AAV9:cTnT-DDX21, AAV9:cTnT-NC, AAV9:cTnT-sh-NC and AAV9:cTnT-sh-DDX21, respectively). Additionally, the I/R+A-485 group received intraperitoneal injections of the cAMP response element-binding protein (CREB) binding protein inhibitor A-485, while the I/R+PBS group was injected with an equivalent volume of phosphate-buffered saline (PBS) as the control. Echocardiography was performed on postoperative days 1 and 28 to evaluate cardiac function (left ventricular ejection fraction and fractional shortening). At 28 days post-surgery, mice were euthanized and heart tissues were harvested for histological sectioning. Myocardial fibrosis was evaluated using Masson′s trichrome staining. In vitro, primary cardiomyocytes were isolated from neonatal day 1 C57BL/6J mice using enzymatic digestion method. Cardiomyocytes were transfected with plasmids or small interfering RNA (siRNA). The cardiomyocytes transfected with DDX21-siRNA were assigned to the siDDX21 group, those transfected with the DDX21 plasmid were assigned to the DDX21 group, and those transfected with the corresponding empty plasmid or siRNA were assigned to the NC group. Additionally, cardiomyocytes were treated with A-485 (A-485 group) or PBS (PBS group). An oxygen-glucose deprivation/reoxygenation (OGD/R) model was used to simulate cellular injury. Transcriptome sequencing was performed to identify downstream mechanisms of DDX21. Differential gene expression analysis was conducted using software such as DESeq2, and alternative splicing events in the mRNA transcriptome were analyzed using rMATS software. Mitochondrial superoxide, mitochondrial membrane potential, ATP content, and mitochondrial respiratory chain complex enzyme activity in cardiomyocytes were detected using immunofluorescence staining and commercial assay kits. The oxidative phosphorylation level of the cells was assessed by the Seahorse extracellular flux analyzer. Acetylated DDX21 levels were measured using co-immunoprecipitation and Western blot assays.Results:The expression levels of DDX21 in myocardium from the Bama pigs and mice in the I/R injury model were significantly higher than those in the sham group (all P<0.001). Echocardiographic results showed that at 28 days post-surgery, compared to the I/R+NC group, the I/R+DDX21 group exhibited higher left ventricular ejection fraction and fractional shortening, while the I/R+sh-DDX21 group showed lower values; Masson staining results demonstrated that, compared to the I/R+NC group, the myocardial fibrosis area in the I/R+DDX21 group was significantly reduced, whereas it was significantly increased in the I/R+sh-DDX21 group (all P<0.001). Transcriptomic sequencing results suggested that DDX21 may influence myocardial injury by regulating mitochondrial metabolic activity. In vitro, compared to the OGD/R+NC group, the OGD/R+DDX21 group exhibited lower mitochondrial superoxide levels, higher polymer/monomer ratio, maximal oxygen consumption, reserve capacity, and ATP content. In contrast, the OGD/R+siDDX21 group showed the opposite results, with reduced activity of mitochondrial respiratory chain complex V (all P<0.05). Mechanistically, rMATS software and other analyses indicated that knockdown of DDX21 affected the alternative 3′ splicing sites of ATP5J precursor mRNA, inhibiting the splicing of certain exonic sequences. Overexpression of DDX21 upregulated both mRNA and protein levels of ATP5J. Co-immunoprecipitation experiments showed that, compared to the PBS group, acetylated DDX21 levels were reduced in the A-485 group. Further in vivo experiments showed that, compared to the I/R+PBS group, the I/R+A-485 group exhibited higher left ventricular ejection fraction and fractional shortening, and a lower proportion of left ventricular fibrosis (all P<0.001). Conclusions:DDX21 improves cardiomyocyte energy metabolism and alleviates I/R injury by regulating the alternative splicing of ATP5J. A-485 holds potential as a novel small molecule candidate for the treatment of myocardial injury.

Objective:To investigate the biological role and molecular mechanism of checkpoint kinase 1 (CHK1) in delaying cardiac aging in mice.Methods:In vitro, a senescence model of H9C2 cells (a cardiomyocyte line) was induced using H 2O 2. A control group (without H 2O 2 treatment) and three H 2O 2-treated groups (at concentrations of 10, 30, and 50 μmol/L) were set up. The CCK-8 assay was used to evaluate the proliferative activity of cells in each group; Western blot analysis was employed to detect the expression level of CHK1; and quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the messenger RNA (mRNA) expression levels of P16 and interleukin-1β (IL-1β). In vivo, C57BL/6 wild-type mice aged 2 months ( n=15) and 24 months ( n=40), as well as myocardial-specific CHK1-overexpressing (CHK1-TG) mice aged 2 months ( n=15) and 24 months ( n=40), were selected. The mice were divided into four groups based on age and genotype: 2-month-old wild-type (WT-2M), 24-month-old wild-type (WT-24M), 2-month-old CHK1-TG (CHK1-TG-2M), and 24-month-old CHK1-TG (CHK1-TG-24M). Echocardiography was used to evaluate cardiac function of mice in the WT-24M and CHK1-TG-24M groups. Western blot analysis was conducted to measure the protein expression levels of CHK1, total Ras-related protein 1 (Rap1), NADPH oxidase 4 (Nox4), and Rap1-guanosine triphosphate (Rap1-GTP, the active form of Rap1) in the cardiac tissue of mice in each group. qRT-PCR was used to detect the messenger RNA (mRNA) expression levels of CHK1, collagen type Ⅰ (Coll1), matrix metalloproteinase-2 (Mmp2), alpha-smooth muscle actin (α-SMA), P53, P21, P16, thioredoxin 1 (Trx1), thioredoxin reductase (TrxR), glutathione recluctase (GR), Rap1, and Nox4. Immunofluorescence staining was employed to determine the protein expression levels of P53, P21, and P16, as well as the proportion of histone H2AX phosphorylation-positive cells. Dihydroethidium (DHE) staining was used to detect the relative intensity of DHE. Wheat germ agglutinin staining, HE staining, Masson staining and Sirius red staining were applied to measure the cross-sectional area of cardiomyocytes, cardiac morphology, and myocardial fibrosis area. Mice in the WT-24M and CHK1-TG-24M groups were intraperitoneally injected with the Rap1 activity inhibitor GGTI298 (25 μmol/kg). After injection, the oxidative stress damage in the cardiac tissue of the mice was detected, along with the mRNA expression levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P16, P21, and P53). Results:A concentration of 30 μmol/L was determined as the optimal concentration for establishing an H 2O 2-induced senescence model of myocardial cells in vitro. The expression level of CHK1 in H9C2 cells of the 30 μmol/L H 2O 2 group was lower than that in the control group ( P<0.05). Echocardiographic examination showed that the left ventricular ejection fraction ((61.08±1.13)% vs. (52.55±2.02)%) and fractional shortening ((31.80±1.27)% vs. (25.18±1.59)%) of mice in the CHK1-TG-24M group were higher than those in the WT-24M group (both P<0.05). qRT-PCR and Western blot analysis revealed that, compared with the WT-24M group, mice in CHK1-TG-24M group had higher expression levels of CHK1 and its mRNA, lower expression levels of Nox4 and its mRNA, and higher expression level of Rap1-guanosine triphosphate (Rap1-GTP) (all P<0.05). However, there were no statistically significant differences in the total expression level of Rap1 and its mRNA between the two groups (both P>0.05). In addition, the mRNA expression levels of Coll1, Mmp2, and α-SMA in myocardial tissue of mice in the CHK1-TG-24M group were lower than those in the WT-24M group (all P<0.05). Immunofluorescence staining results showed that the expression levels of P53, P21, and P16 proteins, as well as the proportion of phosphorylated histone H2AX-positive cells in myocardial tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). qRT-PCR further confirmed that the mRNA expression levels of the above-mentioned proteins in cardiac tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). DHE staining results indicated that the relative intensity of DHE in cardiac tissue of mice in the CHK1-TG-24M group was lower than that in the WT-24M group ( P<0.05). Meanwhile, the left ventricular internal diameter, cross-sectional area of cardiomyocytes, and myocardial fibrosis area of mice in the CHK1-TG-24M group were all smaller than those in the WT-24M group (all P<0.05). Furthermore, the degree of DNA damage in cardiac tissue as well as the mRNA levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P53, P21, P16) in mice of the WT-24M+GGTI298 group were higher than those in the WT-24M group and the CHK1-TG-24M+GGTI298 group (all P<0.05). Conclusion:CHK1 alleviates oxidative stress-induced damage in mouse cardiomyocytes by activating the Rap1/Nox4 signaling pathway, thereby delaying cardiac aging in mice.

Objective To explore the role of β-1,3-galactosyltransferase 2(B3galt2)in mice with cerebral ischemic injury.Methods Adult male C57BL/6J mice were randomly divided into the sham,suture-occluded middle cerebral artery occlusion(MCAO)model,MCAO model+lentiviral vector control(LV-GFP),and MCAO model+lentiviral vector overexpression B3galt2(LV-B3galt2)groups,with six mice in each group.Neurological deficit scoring and rotating rod experiments were performed 24 h after ischemia in each group,and 2,3,5-triphenyltetrazolium chloride(TTC)staining was used to determine the infarction volume.The number of neurons in the ischemic cerebral cortex was determined in each group using Nissl staining.The levels of oxidative stress-related factors in the brain tissues were detected using the relevant kits.Results Compared with the sham group,the MCAO model group showed increased infarct volume and neurological deficits(P<0.05),significantly decreased number of neurons in the ischemic cerebral cortex and levels of super-oxide dismutase(SOD)and glutathione peroxidase(GSH)(all P<0.05),and significantly increased levels of reactive oxygen species(ROS)and malondialdehyde(MDA)(all P<0.05).Compared with the MCAO model group,the LV-B3galt2 group had reduced volume of cerebral infarction,significantly improved neurological deficits(all P<0.05),significantly increased number of neurons in the ischemic cerebral cortex of mice,significantly decreased levels of ROS and MDA(P<0.05),and significantly elevated levels of SOD and GSH(all P<0.05).Conclusion B3galt2 overexpression can reduce brain injury in an ischemic damage mouse model,and its mechanism may be through the inhibition of oxidative stress reactions.

Objective To clarify the characteristics of shock wave sources generated at different medium interfaces.Methods The experiment used an in vitro adjustable impact pressure shock wave generation and signal acquisition system combined with a flexible PVDF sensor.The waveform of the shock wave generated by the applicator at the interface of different media(soft tissue-mimicking phantom,water and air)was explored.The characteristics of the shock wave source in the time and frequency domains were analyzed.Results When the same impact pressure was applied,shock waveforms generated at the interfaces of the phantom and water exhibited similar characteristics from a time-domain perspective.At the same time,both differed significantly from those generated at the air interface,where the absolute values of the positive and negative pressures were noticeably reduced.The characteristics of the shockwave spectra in various media revealed three distinct peak frequencies,with the modulation frequencies varying in the phantom(12.2 kHz),water(8.5 kHz),and air(7.2 kHz).In contrast,the carrier frequency remained relatively constant(between 82 and 83 kHz).When different impact pressures were applied,there was little influence on the waveform at the same medium interface,indicating that the impact pressure affected only the shockwave amplitude and not the peak frequency.As the impact pressure increases,the absolute values of the positive and negative pressures at the medium interface increase linearly.Conclusions Shockwave sources can be effectively measured using a flexible PVDF sensor.Shock waves generated at different medium interfaces exhibit temporal and spectral differences,indicating that the characteristics of shock wave propagation in air or water cannot be substituted for those in biological soft tissues.These findings provide crucial information for evaluating shockwave devices and formulating treatment protocols in the clinic.