miR-218-5p减轻高糖诱导的小鼠肾足细胞系MPC5损伤OA

Objective To investigate the effect of miR-218-5p on high glucose(HG)-induced injury in a mouse podocyte cell line MPC5 and its potential mechanism involving targeting tissue inhibitor of metalloproteinase 2(TIMP2).Methods MPC5 cells were divided into the following groups:control group,HG group,NC-mimics group,miR-218-5p-mimics group,miR-218-5p-mimics+pcDNA-NC group,and miR-218-5p-mimics+pcDNA-TIMP2 group.All groups except the control group were treated with 30 mmol/L glucose for 24 hours to induce injury.The expression levels of miR-218-5p and TIMP2 mRNA were detected by RT-qPCR.Cell proliferation and apoptosis were assessed using the CCK-8 assay and flow cytometry,respectively.The activities of reactive oxygen species(ROS)and superoxide dismutase(SOD),as well as the content of malondialdehyde(MDA),were meas-ured using ELISA kits.Protein expression levels were detected by Western blot.The targeting relationship between miR-218-5p and TIMP2 was verified by a dual-luciferase reporter assay.Results Compared with the control group,the HG group showed decreased A450 value,miR-218-5p expression,and SOD activity,but increased apoptosis rate,TIMP2 mRNA and protein expression,ROS activity,MDA content,and cleaved caspase-3 expression(P＜0.05).Compared with the HG and NC-mimics groups,the miR-218-5p-mimics group exhibited an increased A450 value,elevated miR-218-5p expression,and higher SOD activity,whereas the apoptosis rate,TIMP2 mRNA and protein expression,ROS activity,MDA content,and cleaved caspase-3 expression were decreased(P＜0.05).Furthermore,compared with the miR-218-5p-mimics group and the miR-218-5p-mimics+pcDNA-NC group,the miR-218-5p-mimics+pcDNA-TIMP2 group displayed a reduced A450 value and SOD activity,alongside an increased apoptosis rate,elevated TIMP2 mRNA and protein expression,higher ROS activity,increased MDA content,and enhanced cleaved caspase-3 expression(P＜0.05).The dual-luciferase reporter assay confirmed that miR-218-5p could directly target and negatively regulate TIMP2.Conclusions Overexpression of miR-218-5p protects against HG-induced podocyte injury,and this protective effect may be mediated through the negative regulation of TIMP2.