Effects Of High Glucose And High LDL On Oxidative Stress In Podocytes

Objective1.To investigate the influence of high glucose and high low-density lipoprotein (LDL)on the contents of hydroxy radical(·OH),malondialdehyde(MDA)and the activity of superoxide dismutase(SOD)in cultured podocytes and to explore the effects of high glucose and high LDL on oxidative stress in podocytes.2.To observe the effects ofα-lipoic acid(ALA)on the oxidative stress induced by high glucose and high LDL in cultured podocytes and to explore the protection ofα-lipoic acid against the oxidative stress in podocytes.MethodsMouse podocyte clone 5(MPC-5)were incubated in vitro.Cultured cells were divided into 8 groups:control group;hyperosmolality group;HG group;HLDL group; HG+HLDL group;ALA+HG group;ALA+HLDL group;ALA+HG+HLDL group. Then the cells were cultured for 0,24,48,72 hours respectively.The levels of MDA,·OH and activity of SOD in MPC-5 were measured by spectrophotomery.Result1.The effects of high glucose on oxidative stress in podocytes and protective effect of ALA on oxidative stressThe levels of MDA and·OH were significantly higher and the activity of SOD was obviously lower in HG group at different time points(except 0 hour)compared than that in control group.The levels of MDA and·OH increased and the activity of SOD decreased in a time-dependent way.But the differences were not significant between hyperosmolality group and control group.Compared with HG group,The levels of MDA and·OH were obviously lower and the activity of SOD was markedly higher in ALA+HG group.2.The effects of high LDL on oxidative stress in podocytes and protective effect of ALA on oxidative stressThe levels of MDA and·OH were significantly higher and the activity of SOD was obviously lower in HLDL group at different time points(except 0 hour)than that in control group,which were dependent of time.Compared with HLDL group,The levels of MDA and·OH were obviously lower and the activity of SOD was markedly higher in ALA+HLDL group.3.The effects of high glucose and high LDL on oxidative stress in podocytes and protective effect of ALA on oxidative stressHigh glucose and high LDL synergistically increased the level of MDA and·OH and decreased the activity of SOD.The levels of MDA and·OH increased and the activity of SOD decreased in a time-dependent manner.Compared with HG+HLDL group,The levels of MDA and·OH were obviously lower and the activity of SOD was markedly higher in ALA+HG+HLDL group.Conclusion1.High glucose and high LDL could induce oxidative stress in podocytes,which is in a time-dependent way.2.The combined use of high glucose and high LDL can promote oxidative stress synergistically in podocytes.3.ALA could protect podocytes from oxidative stress induced by high glucose and high LDL.4.Metabolic disorders of glucose and lipid play crucial and complicated roles in the development of DN.Lipid-lowering and antioxidant therapy are also necessary besides improving glucose control.