[Study on the mechanism of paeonol in improving low-density lipoprotein-induced human vascular endothelial cell injury].

OBJECTIVE: To investigate the effects of paeonol on low-density lipoprotein-induced human vascular endothelial cell injury and its molecular mechanisms. METHODS: Human umbilical vein endothelial cells (HUVECs) were divided into 9 groups, normal control (NC) group, ox-LDL group (100 ng/L ox-LDL), low, medium, and high-dose paeonol groups (60 µmol/L, 120 µmol/L, 240 µmol/L paeonol+100 ng/L ox-LDL), ox-LDL+small interfering RNA negative control (si-NC) group, ox-LDL+circ_0003204 small interfering RNA (si-circ_0003204) group, middle dose group+ox-LDL+circ_0003204 overexpression negative control (pcDNA-NC) group, middle dose group+ox-LDL+circ_0003204 overexpression (pcDNA-circ_0003204) group, three replicate wells in each group. MTT flow cytometry, and Western blot were used to detect cell proliferation, apoptosis and protein (CDK2, Bcl2, p27, Bax) expressions, respectively. Malondialdehyde (MDA) and superoxide dismutase (SOD) kit were used to detect MDA content and SOD activity; real-time quantitative PCR (RT-qPCR) was used to detect the expression of circ_0003204. RESULTS: Compared with the NC group, the proliferation activity, protein expressions of CDK2 and Bcl2, and SOD activity of HUVECs in the ox-LDL group were decreased significantly (P＜0.05), and the apoptosis rate, protein expressions of p27 and Bax, MDA content, and circ_0003204 expression were increased significantly (P＜ 0.05). Compared with the ox-LDL group, the proliferation activity, protein (CDK2, Bcl2) expressions and SOD activity of HUVECs in the low, medium and high dose paeonol groups were increased significantly (P＜0.05), and the apoptosis rate, protein (p27, Bax) expressions, MDA content And circ_0003204 expression were decreased significantly (P＜ 0.05). Compared with ox-LDL+si-NC group, the proliferation activity, protein (CDK2, Bcl2) expressions, SOD activity of HUVECs in ox-LDL+si-circ_0003204 group were increased significantly (P＜0.05), the apoptosis rate, protein (p27, Bax) expressions, and the content of MDA were decreased significantly (P＜0.05). Compared with the middle-dose+ox-LDL+pcDNA-NC group, the HUVECs proliferation activity, protein (CDK2, Bcl2) expressions, and SOD activity in the middle-dose+ox-LDL+pcDNA-circ_0003204 group were decreased significantly (P＜0.05), and the levels of circ_0003204, apoptosis rate, protein (p27, Bax) expressions and MDA content were increased significantly (P＜0.05). CONCLUSION: Paeonol can inhibit ox-LDL-induced apoptosis and oxidative stress of human umbilical vein endothelial cells, and alleviate human umbilical vein endothelial cell injury. The mechanism of action may be related to the down-regulation of circ_0003204 expression.