Objective To investigate the effect of"Jiaji"(EX-B 2)-electroacupuncture(EA)preconditioning on the myocardium and expression of cytochrome P 450 signaling pathways of myocardial cells in myocardial ischemia-reperfusion injury(MI/RI)rats.Methods Sixty male Wistar rats were randomly divided into sham operation

model

Jiaji

Neiguan(PC 6)

Yanglingquan(GB 34)and Quchi(LI 11)groups(n=10in each group).MI/RI model was established by occlusion of the descending anterior branch of the left coronary artery.EA preconditioning was respectively applied to EX-B 2

PC 6

GB 34 and LI 11for30 min

once daily for 7days.The ECG-ST segment was detected before and after the modeling.The contents of serum creatine kinase-MB(CK-MB)and lactate dehydrogenase(LDH)were detected by ELISA and microplate method separately.The expression levels of myocardial CYP 450 related genes cyp 1a1

cyp 2b2

cyp 2c11

cyp 4a2 were detected by Real-time PCR.Results Thirty minutes after ligation the changes of ECG-ST segment displacement of the Jiaji group and Neiguan group were significantly lower than that of the model group(P<0.01)

and the change was significantly lower in the Neiguan group than in the model group(P<0.01)30minutes after reperfusion.Compared with the sham operation group

the activities of serum CK-MB and LDH were significantly increased in the model group(P<0.01).Compared with the model group

the activities of serum CK-MB and LDH were significantly decreased in the Jiaji

Neiguan and Yanglingquan groups(P<0.01).Compared with the Jiaji group

the activity of serum LDH was significantly increased in the Quchi group

while the activities of serum CK-MB were significantly increased in the Quchi and Yanglingquan groups(P <0.05).Compared with the sham operation group

the expression levels of myocardial cyp 1a1 and cyp 2b2 mRNAs were significantly higher in the model group(P<0.01)

while the expression of cyp 2c11 mRNA was lower(P<0.01).Compared with the model group

the expression levels of cyp 1a1 and cyp 4a2 mRNAs were lower in the Jiaji

Neiguan and Yanglingquan groups(P<0.01)

while the expressions of cyp 2b2 and cyp 2c11 mRNAs were higher(P<0.01).Compared with the Jiaji group

the expression of cyp 1a1 mRNA was lower in the Neiguan group

while the expression of cyp 2b2 mRNA was higher(P<0.05).Conclusion EA preconditioning at Jiaji(EX-B 2)can reduce serum myocardial enzymes of myocardial ischemia-reperfusion rats

lower the ST segment of electrocardiogram

up-regulate myocardial CYP 450 epoxygenase cyp 2b2 and cyp 2c11 mRNAs expression

down-regulateω-hydroxylase cyp 1a1 and cyp 4a2 mRNAs expression

thus play a role in myocardial protection.