摘要
Abstract
Objective To explore the mechanism of extracellular superoxide dismutase (EC-SOD) DNA methylation changes in atherosclerosis. Methods Sixteen ApoE-/- mice (ApoE-/- group) were fed with high-fat diet,and 16 C57BL/6 mice (WT group) were fed with ordinary diet without any high-fat component. The serum lipid level, aortic morphology and tissue MDA and ROS content were detected in the 8th, 12th, 16th and 20th weeks after feeding respectively. The EC-SOD and DNA methyltransferase 1 (DNMT1) mRNA levels in the aortic tissues were detected by RT-PCR. EC-SOD DNA methylation level was detected by nested methylation specific PCR. THP-1 was induced into macrophages and divided into three groups: NC group (without any treatment, continue to cultivate), pEGFP-N1 group (added with 10 μl liposome Lipofectamine and 20 μg of empty plasmid vector pEGFP-N1), pEGFP-N1-DNMT1 group (added with 10 μl liposome Lipofectamine and 20 μg recombinant plasmid vector pEGFP-N1-DNMT1), The EC-SOD and DNMT1 protein expressions and EC-SOD DNA methylation level were detected after culture for 24 h. Results In the 8th, 12th, 16th and 20th weeks, TC, LDL and TG of the ApoE-/- group were in increasing trends, and HDL had no significant change, the TC, LDL and TG of the ApoE-/- group were significantly higher than those of the WT group, HDL was significantly lower than that of the WT group (P < 0.05). In the 16th and 20th weeks, the endothelial cells of artery tissue were regularly and orderly arranged in the WT group, while in the ApoE-/- group aortic intima was obviously thickened with inflammatory infiltration. In the 8th, 12th, 16th and 20th weeks, MDA and ROS of the ApoE-/- group were in increasing trends, the MDA and ROS content of the ApoE-/-group was significantly higher than that of the WT group (P < 0.05). EC-SOD mRNA expression level of the ApoE-/-group was significantly lower than that of the WT group, DNMT1 mRNA level and EC-SOD methylation level were significantly higher than those of the WT group (P < 0.05). DNMT1 protein expression and EC-SOD methylation level of the pEGFP-N1-DNMT1 group were significantly higher than those of the pEGFP-N1 group and the NC group, EC-SOD protein level was significantly lower than that of the pEGFP-N1 group and the NC group (P < 0.05). EC-SOD and DNMT1 protein levels and EC-SOD methylation level had no statistically differences between the pEGFP-N1 group and the NC group (P > 0.05). Conclusions Increase of EC-SOD methylation can lead to decrease of EC-SOD expression and weakening of body resistance to oxidative stress reaction, and ultimately results in development of atherosclerosis.关键词
细胞外超氧化物歧化酶/DNA甲基化/DNA甲基转移酶/动脉粥样硬化/氧化应激损伤Key words
extracellular superoxide dismutase/DNA methylation/DNA methyltransferase 1/atherosclerosis/oxidative stress damage分类
医药卫生
