Phenylethanoid glycosides of Callicarpa kwangtungensis Chun exert cardioprotective effect by weakening Na+-K+-ATPase/Src/ERK1/2 pathway and inhibiting apoptosis mediated by oxidative stress and inflammation

Ethnopharmacological relevance: Callicarpa kwangtungensis Chun (C. kwangtungensis) is a very famous herbal medicine with the function of promoting blood circulation and removing blood stasis which is beneficial for cardiovascular disease (CVD). Phenylethanoid glycosides (PGs) are the major class of active ingredients in C. kwangtungensis and present significant anti-oxidative and anti-inflammatory property related to apoptosis. Therefore, this study aimed to investigate the effects of total phenylethanoid glycosides of C. kwangtungensis (CK- PGs) on isoproterenol (ISO) induced myocardial ischemic injury (MI) and the mechanisms related to the apoptosis mediated by oxidative damage and inflammation. Methods: The myocardial ischemia animal model was established as subcutaneous injecting ISO. Echocardiography and biomarkers were employed to determine the degree of myocardial damage. Histopathological changes were observed by hematoxylin and eosin test. The TUNEL staining and activity of caspase-3 were measured to detect the level of apoptosis which is medicated by the oxidative damage detected by the level of MDA, GSH and ROS tested with the kit and the inflammation reflected by TNF-α. The activity of Na+-K+-ATPase (NKA) was detected by the commercial kits, whose expression was measured by im- munohistochemistry analysis. At last, Western blot analysis was used to measure Na+-K+-ATPase/Src/ERK1/2 and Bax/Bcl-2 pathway. Results: CK-PGs showed cardioprotective effect against ISO-induced myocardial ischemic injury evidenced by improving heart function and lowering myocardial injury markers. CK-PGs could inhibit the level of apoptosis as shown by the decrease of the TUNEL-positive cells, the activity of caspase-3 and increase of the expression of Bax. CK-PGs also reduced oxidative stress and inflammation to suppress apoptosis by decreasing the level of ROS, MDA, and increasing GSH activity and lowering the level of TNF-α. In addition, CK-PGs exerted the protection by increasing the activity and the expression of NKA. Meanwhile, Na+-K+-ATPase/Src/ERK1/ 2pathway was weakened for the inhibition of apoptosis. Conclusions: CK-PGs could protect cardiomyocytes from myocardial injury through suppressing Na+-K+- ATPase/Src/ERK1/2 pathway and inhibiting apoptosis mediated by oxidative stress and inflammation