The protective effect of polyphyllin I on myocardial ischemia/reperfusion injury in rats

Myocardial ischemia/reperfusion (I/R) injury has become a global public health concern. An increasing amount of evidence has shown that polyphyllin I (PPI) has anti-apoptotic and antioxidant functions. This study was performed to evaluate the cardioprotective effects of PPI in a rat model of myocardial I/R injury and the underlying mechanism.

We exposed induced a rat model of I/R injury by exposing rat hearts to left anterior descending coronary artery ligation for 30 min, followed by 24 h of reperfusion. Cardiac function was analyzed by echocardiography and HE staining. Myocardial apoptosis, inflammation, and oxidative stress were detected to analyze the PPI's role in I/R injury.

The results showed that pretreatment with PPI improved impaired histological morphology, as shown by histopathological examination. Echocardiography analysis showed that PPI increased the levels of HR, left ventricular ejection fraction (LVEF), and left ventricular wall thickness (LVWT), accompanied by decreased left ventricular end-systolic volume (LVESV). Also, PPI decreased the expression of CK-MB, Mb, cTnI, and LDH. Specifically, PPI also changed the expression of apoptotic makers (Caspase-3, Bax, and Bcl-2), inflammatory cytokines (TNF-α, IL-6, iNOS, and IL-10) and oxidative stress markers (SOD, GSH, ROS, and MDA). Notably, western blot (WB) showed that PPI treatment inhibited the phosphorylation activity of NF-κB p65.

The findings showed that PPI exerted a favorable protective effect on I/R injury by inhibiting the inflammatory response and oxidative stress. It offered new drug candidates for the treatment of myocardial I/R injury.