Abstract: AIM: To study the protection effect of baicalin on isoproterenol (ISO)induced myocardial ischemia in rats and its mechanisms.METHODS: Fortyfive Sprague-Dawley rats were randomly divided into 3 groups.The rats in control group (n =15)received no treatment.The rats in ISO group (n =15)received two times of subcutaneous injection of ISO (20 mg·kg^-1), which was separated by a 24 hours-interval.The rats in baicalin group (n =15)received ISO as described above and received baicalin 50 mg·kg^-1 ip.simultaneously. Two days later the hemodynamic measurement was performed and the serum levels of LDH, CK and TNF-αwere detected.The expression of p38mapk in myocardium was detected by immunohistochemical technique.RESULTS: The heart function of the group treated with baicalin was improved significantly compared with that of control group.The levels of LDH, CK and TNF-αin baicalin group decreased significantly compared with those in control group and the expression of p38mapk in myocardium also decreased markedly.CONCLUSION: Baicalin has protection effect on isoproterenol induced myocardial ischemia in rats, and the effect maybe due to the decrease of TNF-αinduced by reducing the p38mapk expression.

Key words: baicalin, isoproterenol, myocardial ischemia, TNF-α, p38mapk