Salidroside Reduced Ca2+-CaM-CAMKII-Dependent eNOS/NO Activation to Decrease Endothelial Cell Injury Induced by Cold Combined with Hypoxia

Abstract

To investigate vascular endothelium damage in rats exposed to hypoxic and cold and the effect of salidroside in protecting against this damage. A rat isolated aortic ring hypoxia/cold model was established to simulate exposure to hypoxic and cold. The levels of endothelial cell injury markers were measured by ELISA. TEM was performed to observe the ultrastructure of vascular ring endothelial cells. In vitro assays were performed to verify the effect of salidroside on endothelial cells. CCK-8 and flow cytometry were performed to analyze endothelial cell survival and apoptosis, respectively. Ca²⁺ concentrations were measured by Flow cytometry, and the expressions of NOS/NO pathway-related proteins were measured by WB. Endothelial cell damage, mitochondrial swelling, autophagy, and apoptosis were increased in the hypoxia group and hypoxia/hypothermia group. All of these effects were inhibited by salidroside. Moreover, exposure to cold combined with hypoxia reduced the NO levels, Ca²⁺ concentrations and NOS/NO pathway-related protein expression in the hypoxia group and hypoxia/hypothermia group. Salidroside treatment reversed these changes. Salidroside protected against endothelial cell injury induced by cold and hypoxia through reduction of Ca²⁺-CaM-CAMKII-dependent eNOS/NO activation, thereby preventing mitochondrial damage, reducing ROS levels, and inhibiting apoptosis.

Keywords: Aglycones; Endothelial cell; Hypoxia/hypothermia; Salidroside; eNOS/NO.