NOS2 and myocardial ischemia: In the present study, we also found that BYHWD pre-treatment could significantly decrease the levels of NO and iNOS in serum and the iNOS expression in myocardial tissues compared with those in the model group, suggesting that BYHWD can decrease the NO level in serum by down-regulating the expression of iNOS after myocardial ischemia induced by ISO.