AIM:To investigate the mechanism by which exosomes(EXOs)derived from neural stem cells(NSCs)pretreated with astragaloside IV(ASIV)alleviate brain damage in rats after ischemic stroke.METHODS:Rat NSCs were isolated from fetal rats within 24 h of birth,cultured for 3 d,and subsequently treated with ASIV for additional 5 d.The EXOs from untreated NSCs and ASIV-pretreated NSCs(ASIV-EXOs)were isolated via ultracentrifugation of the cell supernatant.These EXOs were characterized using Western blot to detect specific markers such as CD63,tumor sus-ceptibility gene 101(TSG101)and calnexin.Nanoparticle analysis was employed to determine the size,and the morpholo-gy of the EXOs was observed under electron microscope.Six to eight-week-old SD male rats were randomly assigned to 6 groups:sham group,middle cerebral artery occlusion/reperfusion(MCAO/R)model group,edaravone(EDA)treatment(MCAO/R+EDA)group,EXOs treatement(MCAO/R+EXOs)group and ASIV-EXOs treatment(MCAO/R+ASIV-EXOs)group.Tail vein injections were administered within 2 h following the successful establishment of the MCAO/R model.The Zea Longa method was utilized to evaluate neurological deficits,while the TTC method was employed to assess brain infarc-tion.Pathological changes were examined through HE staining,and TUNEL and caspase-1 immunofluorescence double staining were conducted to detect cellular pyroptosis.Serum levels of interleukin-1β(IL-1β)and IL-18 were measured us-ing ELISA,and Western blot was performed to evaluate the expression of caspase-1,nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3),apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),gasdermin D(GSDMD),and IL-18 proteins in the ischemic area of the rat cerebral cortex across all groups.RE-SULTS:The MCAO/R group exhibited significantly higher neurological deficit scores compared to the sham group(P＜0.01)and lower scores in the administered groups relative to the MCAO/R group(P＜0.05).Cerebral infarction was mark-edly increased in the MCAO/R group compared to the sham group(P＜0.01),whereas the infarction area was reduced in the administered groups compared to the MCAO/R group(P＜0.05).Serum levels of IL-1β and IL-18 were significantly el-evated in the MCAO/R group versus the sham group(P＜0.01)and were lower in the administered groups compared to the MCAO/R group(P＜0.01).Moreover,IL-1β and IL-18 levels in the MCAO/R+ASIV-EXOs group were lower than those in the MCAO/R+EXOs group(P＜0.05).HE staining revealed pronounced sieve-like infarction foci in the ischemic area of the rat cerebral cortex in MCAO/R group,characterized by disorganized neuronal arrangements,reduced or absent Nys-trom's vesicles,shrunken or fragmented nuclei,and numerous red neurons.In contrast,drug-treated groups exhibited milder pathological changes with clearer neuronal structures and a significant reduction in red neuron counts.Immunofluo-rescence double staining indicated a significant increase in double-positive cells in the MCAO/R group compared to the sham group(P＜0.01),with a decrease in double-positive cells in the administered groups relative to the MCAO/R group(P＜0.05)and a further reduction in the MCAO/R+ASIV-EXOs group compared to the MCAO/R+EXOs group(P＜0.05).The expression levels of caspase-1,NLRP3,ASC,IL-18 and GSDMD proteins in the ischemic region of the rat cerebral cortex were significantly reduced in the administered groups compared to the MCAO/R group(P＜0.01),with further re-duction observed in the MCAO/R+ASIV-EXOs group compared to the MCAO/R+EXOs group(P＜0.05).CONCLU-SION:Exosomes derived from ASIV-pretreated NSCs attenuate brain damage in ischemic stroke rats,potentially through a mechanism involving the inhibition of pyroptosis mediated by the NLRP3/caspase-1 pathway.

AIM:To investigate the mechanism by which exosomes(EXOs)derived from neural stem cells(NSCs)pretreated with astragaloside IV(ASIV)alleviate brain damage in rats after ischemic stroke.METHODS:Rat NSCs were isolated from fetal rats within 24 h of birth,cultured for 3 d,and subsequently treated with ASIV for additional 5 d.The EXOs from untreated NSCs and ASIV-pretreated NSCs(ASIV-EXOs)were isolated via ultracentrifugation of the cell supernatant.These EXOs were characterized using Western blot to detect specific markers such as CD63,tumor sus-ceptibility gene 101(TSG101)and calnexin.Nanoparticle analysis was employed to determine the size,and the morpholo-gy of the EXOs was observed under electron microscope.Six to eight-week-old SD male rats were randomly assigned to 6 groups:sham group,middle cerebral artery occlusion/reperfusion(MCAO/R)model group,edaravone(EDA)treatment(MCAO/R+EDA)group,EXOs treatement(MCAO/R+EXOs)group and ASIV-EXOs treatment(MCAO/R+ASIV-EXOs)group.Tail vein injections were administered within 2 h following the successful establishment of the MCAO/R model.The Zea Longa method was utilized to evaluate neurological deficits,while the TTC method was employed to assess brain infarc-tion.Pathological changes were examined through HE staining,and TUNEL and caspase-1 immunofluorescence double staining were conducted to detect cellular pyroptosis.Serum levels of interleukin-1β(IL-1β)and IL-18 were measured us-ing ELISA,and Western blot was performed to evaluate the expression of caspase-1,nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3),apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),gasdermin D(GSDMD),and IL-18 proteins in the ischemic area of the rat cerebral cortex across all groups.RE-SULTS:The MCAO/R group exhibited significantly higher neurological deficit scores compared to the sham group(P＜0.01)and lower scores in the administered groups relative to the MCAO/R group(P＜0.05).Cerebral infarction was mark-edly increased in the MCAO/R group compared to the sham group(P＜0.01),whereas the infarction area was reduced in the administered groups compared to the MCAO/R group(P＜0.05).Serum levels of IL-1β and IL-18 were significantly el-evated in the MCAO/R group versus the sham group(P＜0.01)and were lower in the administered groups compared to the MCAO/R group(P＜0.01).Moreover,IL-1β and IL-18 levels in the MCAO/R+ASIV-EXOs group were lower than those in the MCAO/R+EXOs group(P＜0.05).HE staining revealed pronounced sieve-like infarction foci in the ischemic area of the rat cerebral cortex in MCAO/R group,characterized by disorganized neuronal arrangements,reduced or absent Nys-trom's vesicles,shrunken or fragmented nuclei,and numerous red neurons.In contrast,drug-treated groups exhibited milder pathological changes with clearer neuronal structures and a significant reduction in red neuron counts.Immunofluo-rescence double staining indicated a significant increase in double-positive cells in the MCAO/R group compared to the sham group(P＜0.01),with a decrease in double-positive cells in the administered groups relative to the MCAO/R group(P＜0.05)and a further reduction in the MCAO/R+ASIV-EXOs group compared to the MCAO/R+EXOs group(P＜0.05).The expression levels of caspase-1,NLRP3,ASC,IL-18 and GSDMD proteins in the ischemic region of the rat cerebral cortex were significantly reduced in the administered groups compared to the MCAO/R group(P＜0.01),with further re-duction observed in the MCAO/R+ASIV-EXOs group compared to the MCAO/R+EXOs group(P＜0.05).CONCLU-SION:Exosomes derived from ASIV-pretreated NSCs attenuate brain damage in ischemic stroke rats,potentially through a mechanism involving the inhibition of pyroptosis mediated by the NLRP3/caspase-1 pathway.

Objective: To investigate the positive rate for 2019-nCoV tests and co-infections in Wuhan district. Methods: A total of 8 274 cases in Wuhan were enrolled in this cross-sectional study during January 20 to February 9, 2020, and were tested for 2019-nCoV using fluorescence quantitative PCR. Both respiratory tract samples (nasopharynx, oropharynx, sputum and alveolar lavage fluid) and non-respiratory tract samples (urine, feces, anal swabs, blood and conjunctival sac swabs) were collected. If both orf1ab and N genes are positive, they are classified as nucleic acid test positive group; if both orf1ab and N genes are negative, they are classified as negative group; if single gene target is positive, they are classified as suspicious group. Individuals were divided into male group and female group according to sex. At the same time, 316 patients were tested for 13 respiratory pathogens by multiplex PCR. Results: Among the 8 274 subjects, 2 745 (33.2%) were 2019-nCoV infected; 5 277 (63.8%) subjects showed negative results in the 2019-nCoV nucleic acid test; and 252 cases (3.05%) was not definitive (inconclusive result). The age of cases with COVID-19 patients and inconclusive cases was significantly higher than that of cases without 2019-nCoV infection (40 vs 56, t=27.569, P<0.001; 52 vs 56, t=6.774, P<0.001). The positive rate of 13 respiratory pathogens multiple tests was significantly lower in 104 subjects who were positive for 2019-nCoV compared with those in subjects who were negative for 2019-nCoV test (5.77% vs 18.39%, χ²=24.105, P=0.003). Four types of respiratory tract samples and five types of non-respiratory tract samples were found to be positive for 2019-nCoV nucleic acid test. Conclusion The 2019-nCoV nucleic acid positive rate in male is higher than in female. Co-infections should be pay close attention in COVID-19 patients. 2019-nCoV nucleic acid can be detected in non-respiratory tract samples.

Objective To compare the heart rate variability (HRV)measurements between ballistocardiogram (BCG) and electrocardiography (ECG).Methods The signals of BCG and ECG of 21 patients were collected synchronously.JJ intervals of BCG and RR intervals of ECG were used to calculate the cardiac periods.The parameters of HRV analysis were calculated in time domain analysis,frequency domain analysis and nonlinear analysis.The results derived from BCG and ECG were compared.Results The parameters of HRV analysis calculated from BCG and ECG had high similarity.The correlation coefficients of SDNN,TP,LF,HF and SD2 between the BCG and ECG methods were high (r =1).The correlation coefficients of rMSSD and SD2 were 0.99 and of PNN50 and LF/HF were 0.98 between the two methods.HRV analysis results derived from the two methods were similar (P ＞ 0.05).Conclusion HRV could also be measured reliably by calculating the JJ interval from BCG.