Sixty male Wistar rats were randomly divided into
sham operation, model, EX-B2, Neiguan (
PC6), Yanglingquan(GB34) and Quchi (LI11) groups (n=10 in each group). The MIRI model was established by occlusion of the descending anterior branch of the left coronary artery for 30 min, followed by reperfusion for 30 min. EA preconditioning (2 Hz/100 Hz, 1 mA) was respectively applied to EX-B2,
PC6, GB34, and LI11 for 30 min, once daily for 7 days. Morphological changes of myocardium were observed by H.E. staining. The ultrastructure of myocardial cells was observed by transmission electron microscope (TEM). The
protein expression levels of myocardial CYP450 (
CYP1A1,
CYP2B2, CYP2C11 and
CYP4A2) were detected by Western blot.
RESULTS: In MIRI rats, myocardial pathological changes as swollen, disorganized arrangement, and partially ruptured myocardial fibers with unclear limit and
necrosis and infiltration of lots of inflammatory cells under microscope, and focal myofilament degeneration, dissolution and
necrosis with interstitial
edema, vague mitochondria with swelling and vacuolation, ruptured and disorganized arrangement of crests under TEM were found in the ischemic area, which was obviously milder in rats of both EX-B2 and
PC6 groups. After modeling, the expression of myocardial
CYP1A1 and
CYP2B2 protein were significantly up-regulated in the model group relevant to the
sham operation group (P<0.05). In EA preconditioning groups, the expression levels of
CYP1A1 and
CYP4A2 proteins in the EX-B2,
PC6 and GB34 groups were obviously down-regulated (P<0.01), and those of
CYP2B2 and CYP2C11
proteins in both EX-B2 and
PC6 groups were markedly up-regulated relevant to the model group (P<0.01). Compared with the EX-B2 group, the expression levels of
CYP1A1,
CYP4A2 proteins in the LI11 group were significantly up-regulated (P<0.05), and
CYP2B2, CYP2C11
proteins were significantly down-regulated (P<0.05). No significant differences were found between the model and
sham operation groups in the expression levels of myocardial CYP2C11 and
CYP4A2 proteins, between the LI11 and model groups in the expression of
CYP1A1,
CYP2B2, CYP2C11 and
CYP4A2, between the GB34 and model groups in the expression of
CYP2B2, CYP2C11 (all P>0.05)..
CONCLUSION: EA preconditioning at EX-B2 and
PC6 can suppress MIRI induced up-regulation of myocardial CYP450 ω-
hydroxylase CYP1A1 and
CYP4A2 expression and further up-regulate the expression of myocardial epoxygenase
CYP2B2 and CYP2C11
proteins in acute MIRI rats, thus playing a role in myocardial protection.