Protective Effect And Mechanism Of Lycium Barbarum Polysaccharides On Diabetic Renal Injury

Objective Streptozotocin(STZ)was used to establish diabetes mellitus(DM)model in rats.The effect and mechanism of LBP on diabetic renal injury were observed.Methods Male SD rats were intraperitoneally injected with STZ(50mg/kg)citric acid buffer solution for 5 consecutive days,and then fasting blood glucose was measured.When the blood glucose level of a rat is 16.7 mmol/L or more,the rat is a diabetic model.Eight diabetic rats in each group were randomly divided into three groups: diabetic group(DM group);LBP(60mg/kg/day)group and LBP(30mg/kg/day)group.In addition,8 normal rats were used as control group.LBP group was administrated by gavage for 12 weeks;Control group and STZ group were given the same volume of water by gavage.At the end of the 12 th week,24 hours urine was collected to measure the content of urine protein,the two items of renal function(serum creatine(SCR),blood urea nitrogen(BUN)).A concentration of 20% urethane was prepared and the rats were anesthetized according to the weight of 1g uratan of 1kg rats.The orbital blood was collected from the internal iliac vein and the fasting blood glucose value was measured.The concentration of serum C-reactive protein(CRP)was measured.ELISA was used to measure the contents of TNF-α and IL-6 in serum.Renal histopathological changes were analyzed.The activities of superoxide dismutase(SOD),glutathione peroxidase(GSH PX),glutathione(GSH)and catalase(CAT)in renal tissue were detected by kit method,and the content of malondialdehyde(MDA)in renal tissue was measured.The expression of p65,ICAM-1 and MCP-1 in renal tissue were determined by Western blot.Results Compared with the control group,the blood glucose of STZ injected rats for5 days increased significantly(≥16.7mmol/L),indicating that the establishment of diabetic rats model was successful.In addition,the levels of serum creatinine,urea nitrogen and CRP in DM group were significantly increased,the ratio of kidney weight to body weight was increased,the arrangement of kidney cells was disordered,the contents of IL-6 and TNF-α in serum were significantly increased,the expression of NF-кB subunits p65,MCP-1 and ICAM-1 in kidney tissue was significantly increased,the contents of MDA in kidney tissue were significantly increased,while the contents of GSH in kidney tissue were significantly increased GSH-Px activity,CAT activity and SOD activity decreased significantly.Compared with DM group,LBP can reduce the level of blood glucose,decreased the contents of serum creatinine,urea nitrogen and CRP,decreased the kidney weight/body weight ratio,improved the renal cell disorder,reduced the content of serum IL-6 and TNF-α,downregulated the protein expression of NF-кB subunits p65,MCP-1 and ICAM-1 in renal tissue,decreased the MDA content and increased the GSH content and the activities of GSH-Px,CAT and SOD in renal tissue in a dose-dependent manner.Conclusion LBP can improve blood glucose level,renal function,oxidative stress level,pathological changes of kidney tissue in diabetic renal injury rats.LBP’s improvement of diabetic renal injury may be due to that LBP can reduce oxidative stress,reduce inflammatory response,and inhibit NF-кB expression.