The role of Tom70 in cardiac microvascular endothelial cell damage induced by high fat and high glucose / 解放军医学杂志

ABSTRACT

Objective To investigate the effect of high glycolipid on mouse cardiac microvascular endothelial cells (MCMECs),clarify the role of Tom70 (translocase of the outer mitochondrial membrane 70,Tom70) in it,and explore the related mechanism.Methods MCMECs cultured with normal glucose medium were divided into normal glucose group (NG,5.5mmol/L),high glucose group (HG,25mmol/L) and HG combined with high fat group (HG+HF,glucose concentration 25mmol/L,500μmol/L,16h).Then,the expression of Tom70 in MCMECs was knocked down by siRNA,and the HG+HF group was further divided into vehicle group,Scramble siRNA group and Tom70-siRNA group.To further confirm the specific mechanism of Tom70 in MCMEC injury induced by high glycolipid,Tom70-siRNA group was subgrouped into N-acetylcysteine (NAC)-free group and NAG-containing group.Accordingly,the apoptosis levels were measured by flow cytometer,the generation of nitric oxide (NO) was detected by ELISA kit,the expressions of Tom70 were determined by immunofluorescence and qRT-PCR,and the levels of reactive oxygen species (ROS) by DHE staining and ELISA kit.Results The apoptosis level increased after exposure to HG,and the generation of NO decreased (P＜0.05),while merging HF could aggravate these injuries (P＜0.05).Moreover,HG inhibited the expressions of Tom70 and promoted the production of ROS in MCMECs (P＜0.05).Compared with HG alone,and combination with HF significantly inhibited the expression of Tom70,and significantly increased the production of ROS (P＜0.05).Most importantly,compared with the vehicle group and Scramble siRNA group,the intracellular ROS content and apoptosis rate increased in the Tom70-siRNA group,while generation of NO was significantly decreased (P＜0.01).In contrast,these damage effects mentioned above were partially reversed by the application of antioxidants NAC (P＜0.05).Conclusions High fat can further aggravate the damage on diabetic MCMECs and Tom70 could exert its effect against cardiac microvascular endothelial injury induced by diabetes via inhibiting oxidative stress.