Objective To explore the polymorphism of tyrosinase (TYR) and melanocortin 1 receptor (MC1R) genes and their mRNA expression levels in relation to coat-color phenotypes in guinea pigs, providing genetic markers for locating dominant traits in guinea pigs. Methods A total of 57 self-bred ordinary-level guinea pigs were selected and divided into three groups based on coat color: white (n=22), variegated (n=22) and black (n=13). The guinea pigs were euthanized with an overdose of pentobarbital sodium via intraperitoneal injection. DNA was then extracted from the dorsal skin tissue. Polymorphism in the coding sequence (CDS) of the exons of the TYR and MC1R genes in each group was detected by cloning and sequencing. The mRNA expression of the two genes in skin tissues was detected by real-time fluorescent quantitative PCR to investigate the relationship between these genes and guinea pig coat color. Results A single nucleotide polymorphism (SNP) site was found in the CDS region of TYR exon Ⅰ, where the base A was replaced by G. All white guinea pigs had the G/G genotype for TYR, while no deep-colored (variegated and black) guinea pigs exhibited the G/G genotype for TYR. Most deep-colored guinea pigs had the A/A genotype, and a few had A/G genotype. The A/A genotype frequency in black guinea pigs was higher than in variegated guinea pigs. A 2 760 bp sequence deletion was identified in the exon of the MC1R gene, marked as the - gene, with non-deleted samples marked as N gene. Most white guinea pigs had the -/- genotype for MC1R, variegated guinea pigs mainly had the -/N genotype, and black guinea pigs mainly had the N/N genotype, with a few showing the -/N. The TYR gene expression level was higher in white guinea pigs, lower in variegated guinea pigs, and intermediate in black guinea pigs, but there was no significant difference among the three groups (P>0.05). The MC1R gene expression level in white guinea pigs was extremely low, while both variegated and black guinea pigs showed significantly higher levels than white guinea pigs (P<0.01). Black guinea pigs showed significantly higher levels than variegated guinea pigs (P<0.05). ConclusionThe TYR and MC1R genes synergistically regulate coat color of guinea pigs. The G-site mutation in the TYR gene may lead to albinism, and the change of N-site in the MC1R gene affects the depth of the coat color.

ObjectiveThis study aims to investigate the dynamic changes in general body parameters, blood glucose, and blood lipid profiles in obese cynomolgus monkeys, exploring the correlations among these parameters and providing a reference for research on the obese cynomolgus monkey model. Methods30 normal male cynomolgus monkeys aged 5 - 17 years old (with body mass index < 35 kg/m² and glycated hemoglobin content < 4.50%) and 99 spontaneously obese male cynomolgus monkeys (with body mass index ≥35 kg/m² and glycated hemoglobin content < 4.50%) were selected. Over a period of three years, their abdominal circumference, skinfold thickness, body weight, body mass index, fasting blood glucose, glycated hemoglobin, and four blood lipid indicators were monitored. The correlations between each indicator were analyzed using repeated measurement ANOVA, simple linear regression, and multiple linear regression correlation analysis method. Results Compared to the control group, the obese group exhibited significantly higher levels of abdominal circumference, skinfold thickness, body weight, body mass index, and triglyceride (P＜0.05). In the control group, skinfold thickness increased annually, while other indicators remained stable. Compared with the first year, the obese group showed significantly increased abdominal circumference, skinfold thickness, body weight, body mass index, triglyceride, and fasting blood glucose in the second year(P＜0.05), with this increasing trend persisting in the third year (P＜0.05). In the control group, the obesity incidence rates in the second and third years were 16.67% and 23.33%, respectively, while the prevalence of diabetes remained at 16.67%. In the obese group, the diabetes incidence rates were 29.29% and 44.44% in years 2 and 3, respectively. Among the 11-13 year age group, the incidence rates were 36.36% and 44.68%, while for the group older than 13 years, the rates were 28.13% and 51.35%. Correlation analysis revealed significant associations (P＜0.05) between fasting blood glucose and age, abdominal circumference, skinfold thickness, body weight, and triglyceride in the diabetic monkeys. Conclusion Long-term obesity can lead to the increases in general physical indicators and fasting blood glucose levels in cynomolgus monkeys, and an increase in the incidence of diabetes. In diabetic cynomolgus monkeys caused by obesity, there is a high correlation between their fasting blood glucose and age, weight, abdominal circumference, skinfold thickness, and triglyceride levels, which is of some significance for predicting the occurrence of spontaneous diabetes.

Objective This study aims to investigate the effects of varying durations of light exposure on body weight and learning and memory abilities of pubertal NIH mice. Methods Forty pubertal NIH mice, evenly split by gender and with similar initial weights, were subjected to a 12 h light-dark cycle for one week. They were then randomly assigned to groups with daily light exposure durations of 0, 6, 12, 18, and 24 hours, with 8 mice in each group. The experimental period lasted for 7 weeks, with the first 5 weeks as the feeding phase under different light exposure conditions, and the last 2 weeks as the behavioral testing phase. Their body weight was monitored, and learning and memory abilities were assessed using the T-maze, object location test, and eight-arm maze tests. Results During the light exposure period, there were no significant differences in body weight among groups (P>0.05). However, the weight gain of mice in the 24 h group was significantly higher than that of the 0 h group and the 6 h group during the second and third weeks of light exposure (P<0.05). After five weeks of light exposure, in the T-maze test, the latency time of the 0 h light exposure group was significantly longer than that of the 12 h group (P<0.01), and the latency time of the 24 h light exposure group was significantly longer than that of the 12 h group (P<0.05). In the object location test, the mice in 12 h group exhibited a higher discrimination index and spent more time observing the new location compared to the other groups, with significant differences in comparison to the 18 h group (P<0.01) and the 24 h group (P<0.05). In the eight-arm maze test, the time to find food, the reference memory error rate, and the working memory error rate in the 12 h group were all lower than those in the 0 h group, with significant differences (P<0.05). Moreover, the working memory error rate in the 24 h group was higher than that in the 12 h group, with significant differences (P<0.05). Conclusion Continuous 24 h light exposure affects body weight gain, while light exposure durations exceeding 18 h or below 6 h per day weaken the learning and memory abilities of NIH mice.

ObjectiveThe utilization of assisted reproductive technology to rescue genetically modified mouse strains with reproductive disorders provides a reference for improving techniques to preserve valuable experimental mouse strains. MethodsIn vitro fertilization-embryo transfer (IVF-ET) technology was performed on 28 strains of infertile male mice aged 9-18 months. Several indicators such as sperm density and sperm motility in infertile male mice were assessed to select the most viable sperm for IVF-ET experiments. Fertility rate, abnormal egg rate, and birth rate were recorded after the birth of the pups. An optimized ovarian transplantation procedure was applied to 12 strains of infertile female mice aged 8-18 months. 6-week-old female mice with the same genetic background were selected as recipients. One intact ovary was removed from each recipient mouse, and the contralateral oviduct was ligated. An ovary from a donor mouse was isolated and transplanted orthotopically into the side where the ovary had been removed in the recipient mouse. Twenty-one days post-surgery, recipient mice were co-housed with 8-week-old wild type male mice of the same genetic background for breeding. Data such as the pregnancy rate and live birth rate of the recipients were recorded after the birth of the pups. ResultsIVF-ET successfully rescued 28 mouse strains, with the oldest male mice being 18 months old. The success rate of the first round of IVF-ET experiments was 89.29% (25/28). The average fertility rate of IVF in infertile male mice was (51.01±14.97)%, the abnormal egg rate was (9.03±5.28)%, and the birth rate of offspring mice was (18.60±7.03)%. 39 out of 40 ovarian transplant recipient mice survived, with a pregnancy rate of 33.33% (13/39) for ovarian transplant recipients, and a live birth rate of 17.95% (7/39). Four mouse strains were successfully rescued using optimized ovarian transplantation technology, with the oldest female mice being 18 months old. 8 strains were not rescued as they failed to produce offspring that survived to sexual maturity. ConclusionIVF-ET is an effective approach for rescuing mice with reproductive disorders caused by different reasons, especially for those beyond the optimal breeding age. Ovarian transplantation technology can also be used as an alternative for aged female mice. But its success rate is relatively lower than that of IVF-ET, and carries a higher experimental risk.

Objective By organizing and implementing a laboratory proficiency validation plan for air change rate testing, this study aims to explore proficiency testing approaches in laboratory animal facilities, assess the current status of relevant laboratories regarding standard application and test capabilities, standardize air change rate testing methods, and ensure the accuracy and reliability of test results. Methods From September to November 2023, the National Institutes for Food and Drug Control (NIFDC) organized a laboratory proficiency validation plan for air change rate testing in laboratory animal facilities (Plan Number: NIFDC-PT-417). The proficiency testing was conducted on-site and consisted of two parts: a written test and practical operation. The written test was open-book. True/false questions focused on participants' understanding of specific clauses in relevant standards, while application-based questions assessed their ability to handle data processing in simulated testing scenarios. The practical operation was conducted according to the relevant criteria of the China National Accreditation Service for Conformity Assessment (CNAS). Two laboratory animal rooms were prepared as proficiency testing samples using a sample splitting approach. These rooms underwent uniformity and stability testing according to CNAS requirements and were approved. Participating laboratories were required to conduct three tests on each of the two laboratory animal rooms, complete the testing and calculation of air change rate within the specified timeframe, and submit their test result reports and original records. Results A total of 27 laboratories registered and participated in the proficiency testing. All participating laboratories submitted their results within the designated timeframe, and the outcomes of all tested laboratories were rated as satisfactory. Conclusion This proficiency validation program objectively and scientifically evaluates the air change rate testing capabilities of selected domestic laboratories, effectively promoting the overall improvement of testing capabilities in the industry. It provides technical support for regulatory authorities to standardize testing institutions and offers reliable references for the purchase of testing services. Through this activity, it was identified that some laboratories need to further enhance their calibration of instruments and the utilization of calibration results. Future efforts should focus on refining related standards to improve the accuracy and reliability of testing.

Objective:To investigate the clinical characteristics of omphalocele, and to assess the risk factors associated with adverse outcomes.Methods:A retrospective cohort study was conducted. Clinical data of 224 patients diagnosed with omphalocele, who were hospitalized at Children′s Hospital, Zhejiang University School of Medicine from January 2013 to December 2022, were collected. Based on their discharge outcomes, the patients were classified into 2 groups: favorable outcomes and unfavorable outcomes. Chi-square test or continuity correction χ2 test or Fisher exact probability method, and Mann-Whitney U test were used for intergroup comparisons. Logistic regression analysis was performed to identify risk factors associated with adverse outcomes in omphalocele. Results:Among the 224 patients with omphalocele, 126 were male. A total of 208 patients (92.9%) had favorable outcomes, while 16 patients (7.1%) had unfavorable outcomes. In the unfavorable outcomes group, 14 patients had giant omphaloceles, while 100 patients had giant omphaloceles in the favorable outcomes group. The rates of herniation of more than two intra-abdominal organs in the hernial sac, congenital heart defects, patent ductus arteriosus, pulmonary hypertension, sepsis and infection of the hernial sac, were all higher in the unfavorable outcomes group compared to the favorable outcomes group (all P<0.05). Patients with unfavorable outcomes had longer mechanical ventilation time, duration of oxygen use, duration of parenteral nutrition, hospital stays, and higher rates of parenteral nutrition-associated cholestasis compared to those with favorable outcomes (all P<0.01). Multivariate Logistic regression analysis indicated that pulmonary hypertension ( OR=9.39, 95% CI 1.20-73.32), sepsis ( OR=8.59, 95% CI 1.32-55.86), and congenital heart defects ( OR=6.55, 95% CI 1.11-38.73) were all independent risk factors for adverse outcomes in omphalocele (all P<0.05). Conclusions:Infants with omphalocele are prone to complications such as cardiovascular malformations, infections, and pulmonary hypertension. Adverse outcomes in omphalocele are associated with pulmonary hypertension, sepsis, and congenital heart defects.

Objective:To analyze the current status of red blood cell transfusion in very preterm infants (VPI) (gestational age at birth <32 weeks) from Chinese Neonatal Network (CHNN) in 2022.Methods:This cross-sectional study was based on the CHNN VPI cohort. It included 6 985 VPI admitted to CHNN 89 participating centers within 24 hours after birth in 2022. VPI with major congenital anomalies or those transferred to non-CHNN centers for treatment or discharged against medical advice were excluded. VPI were categorized based on whether they received red blood cell transfusions, their gestational age at birth, the type of respiratory support received during transfusion, and whether the pre-transfusion hemoglobin levels exceeded the thresholds. General characteristics, red blood cell transfusion rates, number of transfusions, timing of the first transfusion, and pre-transfusion hemoglobin levels were compared among different groups. The incidence of adverse outcomes between the group of VPI who received transfusions above the threshold and those who received transfusions below the threshold were compared. Comparison among different groups was conducted using χ2 tests, Kruskal-Wallis H tests, Mann-Whitney U test, and so on. Trends by gestational age at birth were evaluated by Cochran-Armitage tests and Jonckheere-Terpstra tests for trend. Results:Among the 6 985 VPI, 3 865 cases(55.3%) were male, with a gestational age at birth of 30.0 (28.6, 31.0) weeks and a birth weight of (1 302±321) g. Overall, 3 617 cases (51.8%) received red blood cell transfusion, while 3 368 cases (48.2%) did not. The red blood cell transfusion rate was 51.8% (3 617/6 985), with rates of 77.7% (893/1 150) for those born before 28 weeks gestational age and 46.7% (2 724/5 835) for those born between 28 and 31 weeks gestational age. A total of 9 616 times red blood cell transfusions were administered to 3 617 VPI, with 632 times missing pre-transfusion hemoglobin data, and 8 984 times included in the analysis. Of the red blood cell transfusions, 25.6% (2 459/9 616) were administered when invasive respiratory support was required, 51.3% (4 934/9 616) were receiving non-invasive respiratory support, while 23.1% (2 223/9, 616) were given when no respiratory support was needed. Compared to the non-transfusion group, the red blood cell transfusion group had a higher rate of pregnancy-induced hypertension in mothers, lower rates of born via cesarean section and mother′s antenatal steroid administration, smaller gestational age, lower birth weight, a higher proportion of small-for-gestational-age, multiple births, and proportions of Apgar score at the 5 th minute after birth ≤3 (all P<0.05). They were also less likely to be female, born in hospital or undergo delayed cord clamping (all P<0.01). Additionally, higher transport risk index of physiologic stability score at admission were observed in the red blood cell transfusion group ( P<0.001). The number of red blood cell transfusion was 2 (1, 3) times, with the first transfusion occurring at an age of 18 (8, 29) days, and a pre-transfusion hemoglobin level of 97 (86, 109) g/L. For VPI ≤7 days of age, the pre-transfusion hemoglobin levels for invasive respiratory support, non-invasive respiratory support, or no respiratory support, respectively, with no statistically significant differences between groups ( H=5.59, P=0.061). For VPI aged 8 to 21 days and≥22 days, the levels with statistically differences between groups (both P<0.01). Red blood cell transfusions above recommended thresholds were observed in all respiratory support categories at different stages of life, with the highest prevalence in infants aged 8 to 21 days and≥22 days who did not require respiratory support, at 90.1% (264/273) and 91.1%(1 578/1 732), respectively. The rate of necrotizing enterocolitis was higher in the above-threshold group ( χ2=10.59, P=0.001), and the duration of hospital stay was longer in the above-threshold group ( Z=4.67, P<0.001) compared to the below-threshold group. Conclusions:In 2022, the red blood cell transfusion rate was relatively high among VPI from CHNN. Pre-transfusion hemoglobin levels frequently exceeded recommended transfusion thresholds.

BACKGROUND:Apoptosis plays an important role in secondary brain injury.Therefore,to explore the pathophysiological mechanism of promoting nerve cell survival after traumatic brain injury provides a new direction and theoretical basis for the prevention and treatment of traumatic brain injury. OBJECTIVE:To explore the expression changes of Lnx1 molecule in mammalian cortical neurons after brain injury and the possible mechanism involved in secondary brain injury. METHODS:Eighty adult SD rats were divided into 20 male and 20 female mice in sham operation group and 20 male and 20 female mice in traumatic brain injury group.The traumatic brain injury rat model was established by heavy falling method.At 6,12,24,48,and 72 hours after brain injury,the expression of related molecules in damaged cortical neurons was analyzed by RT-qPCR,western blot assay,and immunofluorescence staining. RESULTS AND CONCLUSION:(1)The brain tissue of traumatic brain injury group was bleeding and obvious tissue injury could be observed.Water content of brain tissue increased after traumatic brain injury.(2)Compared with the sham operation group,the expression of Lnx1 in cortical neurons after traumatic brain injury increased significantly at 24 hours after injury.(3)After traumatic brain injury,the expression of PBK and BCR protein decreased,and the pro-survival factor ctgf increased.(4)These findings suggest that after traumatic brain injury,the expression of Lnx1 is up-regulated in neurons,which may be due to the decrease of the expression of its target molecules PBK and BCR,and further promote the expression of living factor ctgf,which has a protective effect on the damaged neurons.

BACKGROUND:Ferroptosis is a mode of programmed cell death distinct from apoptosis,necrosis,and other novel cellular deaths,which occurs mainly due to accumulated lipid peroxidation.Ferroptosis has been shown to be involved in the pathological process following subarachnoid hemorrhage.Baicalein,serving as an adept sequestered of iron,evinces its prowess by quelling lipid peroxidative cascades.Nonetheless,the enigma lingers as to whether baicalein possesses the capacity to ameliorate neuronal ferroptosis,elicited in the wake of early brain injury after subarachnoid hemorrhage. OBJECTIVE:To investigate the effect and mechanism of baicalein on neuronal ferroptosis after subarachnoid hemorrhage. METHODS:Primary neuronal cells were extracted from C57BL/6L fetal mice at 16-17 days of gestation.Hemoglobin was used to stimulate primary neuronal cells to simulate an in vitro subarachnoid hemorrhage model.The viability of primary neuronal cells treated with baicalein at concentrations of 5,15,25,50,and 100 μmol/L for 24 hours was detected by CCK-8 assay to determine the optimal concentration of baicalein.Primary neuronal cells were divided into control group,hemoglobin group,and hemoglobin+baicalein group.The levels of reactive oxygen species and malondialdehyde in cells were detected by kits.The mRNA expressions of ferroptosis-related markers PTGS2,SLC7A11,and glutathione peroxidase 4 were detected by RT-PCR.The primary neuronal cells were further divided into control group,SLC7A11 inhibitor Erastin group,hemoglobin group,hemoglobin+baicalein group,and hemoglobin+baicalein+Erastin group.The expression of the ferroptosis related markers SLC7A11 and glutathione peroxidase 4 was detected by western blot assay. RESULTS AND CONCLUSION:(1)Baicalein(25 μmol/L)was selected as the following experimental concentration.(2)Compared with the hemoglobin group,the level of malondialdehyde and the level of reactive oxygen species were significantly decreased(P<0.05)in the hemoglobin+baicalein group.(3)Compared with the hemoglobin group,the mRNA expression of PTGS2 significantly decreased,and the mRNA expression of SLC7A11 and glutathione peroxidase 4 significantly increased(P<0.000 1)in the hemoglobin+baicalein group.(4)SLC7A11 inhibitor Erastin could reverse the baicalin-improved ferroptosis effect to a certain extent(P<0.05).(5)The results showed that baicalein could alleviate the ferroptosis of neuronal cells after subarachnoid hemorrhage through the SLC7A11/GPX4 pathway.

BACKGROUND:Stem cell therapy has broad prospects in improving cardiac remodeling after myocardial infarction;however,alteration in the myocardial microenvironment affects the therapeutic efficacy of stem cells.Exercise preconditioning is similar to ischemic preconditioning and can have a protective effect on the myocardium.However,little attention has been paid to the effects and mechanisms of the combined effects of exercise preconditioning and stem cell transplantation. OBJECTIVE:To observe the effect of exercise preconditioning on bone marrow mesenchymal stem cell transplantation in rats with myocardial infarction and to explore the mechanism of local inflammatory microenvironment. METHODS:Eighty female SD rats were randomly divided into sham operation group,model group,transplantation group,and combination group,with 20 rats in each group.The rat model of myocardial infarction was made by ligating the left anterior descending branch of coronary artery.The sham operation group was only threaded without ligature.The transplantation and combination groups were injected with bone marrow mesenchymal stem cells of male rats into the myocardium after modeling.In addition,the combination group also required 8 weeks of treadmill exercise(i.e.,exercise preconditioning)before modeling.Four weeks after stem cell transplantation,exercise performance was measured by incremental exercise exhaustion test;cardiac structure and function were measured by echocardiography;left ventricular hemodynamics was measured by pressure-volume catheterization,and myocardial histopathology was observed by in situ staining and myocardial collagen volume fraction was obtained.Quantitative reverse transcription polymerase chain reaction was used to detect left ventricular pro-inflammatory factor(interleukin-1β,interleukin-6,tumor necrosis factor-α),anti-inflammatory factor(interleukin-10),sex-determining region of Y chromosome,and fetal genes(atrial natriuretic peptide,brain natriuretic peptide,β-myosin heavy chain)mRNA expression level at 1,7 days and 4 weeks after stem cell transplantation. RESULTS AND CONCLUSION:(1)Four weeks after stem cell transplantation:compared with sham operation group,exercise performance,and left ventricular ejection fraction were reduced(P<0.05);myocardial infarction area,cardiomyocyte cross-sectional area,and collagen volume fraction were increased(P<0.05);the mRNA expression of fetal genes and pro-inflammatory factors were up-regulated(P<0.05),and the mRNA expression of interleukin-10 was down-regulated(P<0.05)in the model group.Compared with the model group,exercise performance and left ventricular ejection fraction were increased(P<0.05);myocardial infarction area,cardiomyocyte cross-sectional area,and collagen volume fraction were decreased(P<0.05);mRNA expression of fetal genes and pro-inflammatory factors was down-regulated(P<0.05),and that of interleukin-10 had no significant change(P>0.05)in the transplantation group.Compared with the transplantation group,all the above indicators in the combination group were further improved(P<0.05).(2)One day and 7 days after stem cell transplantation,compared with the transplantation group,the mRNA expression of sex-determining region of Y chromosome in the combination group increased(P<0.05).(3)Correlation analysis showed that interleukin-1β,interleukin-6(except on the 1st day after transplantation),and tumor necrosis factor-α were negatively correlated with the mRNA expression of sex-determining region of Y chromosome(P<0.05),while interleukin-10 was positively correlated with that of sex-determining region of Y chromosome(P<0.05).These findings suggest that exercise preconditioning can enhance the effect of bone marrow mesenchymal stem cell transplantation in rats with myocardial infarction,which is characterized by suppression of cardiac remodeling and further amelioration of cardiac function.The mechanism is related to the improvement of the myocardial inflammatory microenvironment to promote bone marrow mesenchymal stem cell retention and survival.