Objective To study the effect of berberine on arrhythmia caused by stretch of rats' myocardium,in vitro,after myocardial ischemia (MI) for 30 min.Methods The study was carried out in the laboratory of Heilongjiang traditional Chinese medicine university.A total of 40 Wistar rats were randomly (random number) divided into 4 groups,namely normal control group,berberine group、MI group and MI + berberine group.After perfusion of rat' s heart with Langendorff perfusion device,the model of MI was made with ligation of left anterior descending branch for 30 min.Berberine was dissolved in Tyrode' s solution to a concentration of 300 μmol/L.The hearts were stretched for 5 s by 0.2 ml.The effect of stretching was observed for 30 s to record 90％ monophasic action potential (MAPD90),premature ventricular beats (PVB) and ventricular tachycardia (VT).Quantitative data were compared with ANOVA.Qualitative data were compared with a x2 test.Differences with a value of P ＜ 0.05 were considered statistically significant.Results MAPD90 in normal control and MI group obviously prolonged after the hearts were stretched ( P ＜ 0.01 ).And MAPD90 in MI group was even longer than that of normal control group (P＜0.05).Berberine had no influence on MAPD90 before myocardiuml stretched (P ＞0.05),while it could reduce the degree of prolongation in MAPD90 after myocardium stretched (P ＜ 0.05 or P ＜0.01 ).The incidence rate of PVB and VT in normal control and MI group increased after stretched.The berberine in dose of 300 μmol/L could reduce the incidence of PVB and obviously inhibit the occurrence of VT ( P ＜ 0.01 ).Conclusions Berberine could obviously inhibit the occurrence of stretch-inducedarrhythmias after myocardial infarction.

Objective To construct a eukaryotic expression plasmid of pcDNA 3.1-Ag85A-CD226, and to use it as DNA vaccine then further evaluate its immunogenicity through oral administration in a mouse model.Methods The CD226-PCR2.1-ToPo plasmid was used as the template to clone CD 226 gene by PCR.The CD226 gene was then inserted into pcDNA 3.1-Ag85A plasmid to construct the recombinant plas-mid of pcDNA3.1-Ag85A-CD226.After identified by restriction enzyme analysis and sequencing , the re-combinant plasmid was transfected into HEK 293 cells by using lipofection .The expression of Ag85A-CD226 gene in HEK293 cells was detected by RT-PCR, Western blot and indirect immunofluorescence assay .The purified recombinant plasmid was used to prepare the Ag 85A-CD226 DNA vaccine by liposomal encapsula-tion.The vaccine was administered intragastrically to mice .The activities of NK cells , the cytokine levels in the supernatants of spleen cell cultures and the mRNA level of cytokines in the intestines were evaluated to analyze the immunogenicity of Ag85A-CD226 DNA vaccine.Results The Ag85A-CD226 DNA vaccine was prepared successfully .The expression of Ag85A-CD226 fusion protein was detected in HEK293 cells.The activities of NK cells from mice vaccinated with Ag 85A-CD226 DNA vaccine were higher than those from other control groups (P<0.01).The level of TNF-α, IFN-γand IL-2 in the supernatants of spleen cell cul-tures and in the intestines were significantly up-regulated in comparison with other control groups ( P <0.01).The level of IL-4 in the supernatants of spleen cell cultures was down-regulated in the experimental group (P<0.01), but the level of IL-4 in intestines showed no significant difference among the five groups (P>0.05).Conclusion The Ag85A-CD226 DNA vaccine could significantly enhance Th1 type immune responses systemically and in the intestine as in comparison with those vaccinated with single dose of Ag 85A DNA vaccine or CD226 DNA vaccine.