Abstract:

Objective: To observe the effect of schisandrin B (SchB) on cardiac function, infarct size, lactate dehydrogenase
and related protein expression in the isolated heart from rats with myocardial ischemia/reperfusion (I/R) injury and
consequently to explore its protective effect against I/R injury and the underlying molecular mechanism. Methods:
Fifty Wistar rats were randomly divided into five groups: control group (Control), ischemia/reperfusion group (I/R) and
SchB preconditioning group (SchB), PI3K inhibitor group (I/R + SchB + LY294002), and AMPK inhibitor group (I/R +
SchB + Compound C). The Langendorff method was used to establish the isolated rat heart model of I/R injury, ischemia
for 2 h, reperfusion for 5, 15, 30 and 60 min respectively. The +dp/dtmax, −dp/dtmax, left ventricular end-diastolic pressure
(LVEDP), coronary flow (CF), heart rate (HR) and LDH activity in perfusion fluids were observed during I/R period. The
myocardial infarct area was measured with TTC staining and myocardial total Akt, phosphorylation Akt, total GSK-3β and
phosphorylation GSK-3β protein expression were evaluated by the Western blotting technique. Results: SchB significantly
improved the myocardial damage caused by I/R injury, reduced infarct size, and increased the expression of p-Akt and
p-GSK-3β. Conclusion: SchB has protective effects against I/R damage in isolated hearts from rats, which may be related to
the activation of the AMPK and PI3K/Akt signaling pathways.

Key words: schisandrin B, myocardial ischemia/reperfusion, injury, molecular mechanism