Cardiac microvascular endothelial cells (CMECs) regulate the function of cardiomyocytes and blood cells in myocardial ischemia/ reperfusion injury (MIRI) via paracrine methods. Tongxinluo (TXL) is a Traditional Chinese Medicine compound to treat angina pectoris in China, which is constituted of ginseng and other 11 natural products. It is proved to improve the endothelial function and be protective against MIRI. Thus, we aimed to find alterations in paracrine function of CMECs under the hypoxia/reoxygenation (H/R) situation and its modulation by TXL.
CMECs were exposed to different concentrations of TXL for 30 min and then subjected to H/R for 12 h/2 h. Apoptotic rates were measured to determine the optimal concentration. Protein antibody arrays were used to find the alterations of cytokines in conditioned medium (CM) secreted by CMECs. Gene Ontology project was adopted to describe the functions of changed cytokines.
TXL inhibited apoptosis of CMECs dose-dependently under H/R and reached its peak effect at 800 μg/mL. Thirty-three types of cytokines were significantly changed by H/R (19 factors decreased and 14 increased), and TXL at 800μg/ml changed 121 types of cytokines compared to the H/R group (93 factors decreased and 28 increased). The cytokines with significant alterations were involved in cell differentiation and proliferation, positive chemotaxis, and endothelial cell migration. Among these cytokines, bFGF, PDGF and IL-7 were attenuated by H/R and further decreased by TXL, while IL-21, MCP-2 and GROa were increased by H/R but decreased by TXL.
The study elucidated the paracrine function of CMECs in MIRI and partly illuminated the protective mechanisms of TXL.