Preliminary Study Of Protective Mechanisms Of Total Flavonoid Of Listea Coreana Leve. Var On Kidney Damage In Experimental Type2Diabetic Rat

Objective:To explore whether the protective effects of TFLC on kidney damage in experimental T2DM SD rat model were related with reducing oxidative stress and endoplasmic reticulum stress, to provide experimental evidence that TFLC may improve kidney function in T2DM patients.Methods:On the basis of experimental type2diabetes mellitus rat model with an improved method, the model rats were randomly divided into four groups:T2DM, STFLC, LTFLC and FENO group, the treatment groups were treated with400mg/kg/d,600mg/kg/d TFLC and100mg/kg/d FENO respectively for6weeks, fenofibrate was regarded as a positive hypolipidemic drug, meanwhile the normal control (NC) group was set up. At the end of treatment, glucose tolerance test(GTT) and insulin tolerance test(ITT) were used to test glucose tolerance and insulin sensitivity,24h urine were collected to determine urinary albumin levels. Blood serum was taken to detect biochemical indices such as the serum glucose and lipid content. HE, PAS and PASM staining were used to test the pathological changes in kidey.10%kidney homogenate were prepared to determine indices of oxidative stress (SOD, GSH, MDA and CAT levels) and the TG accumulation in kidney. The endoplasmic reticulum stress markers GRP78and CHOP were detected by immunohistochemistry and western blot respectively.Results:①The results of GTT experiment indicated that the blood glucose levels in all treatment groups were lower than T2DM group in30,60,120min, the most significant decrease occurred in LTFLC and FENO group (P<0.05). The results of ITT experiment indicated that the blood glucose levels in all treatment groups were lower than T2DM group, the most obvious reduction occurred in FENO group (P<0.05), the decrease degree of blood glucose in LTFLC group in all time-point were higher than that in STFLC group.②24h urine volume and urinary albumin level in LTFLC group were obviously decreased than those in T2DM rats(P<0.05). Serum indicators such as FBG, HbA1c, TG and TC were all elevated obviously in model group, after treatment all indicators were significantly decreased in LTFLC group.③HE, PAS and PASM staining results indicated that the size of glomeruli was increased, capsular space became narrower, basement membrane was irregularly thicker, and mesenteria matrix increased in DM group. Above-mentioned pathological changes in LTFLC group were improved obviously.④SOD and GSH levels were decreased, MDA and TG levels were increased obviously in T2DM group. TFLC treatment significantly inverted all-above indices and displayed somewhat dose-effect.⑤Results of immunohistochemistry and western blot indicated that the expressions of GRP78and CHOP in kidney were elevated obviously, GRP78were distributed mainly in renal tubules, the expressions of GRP78and CHOP in TFLC treatment group were decreased obviously.Conclusions:TFLC could improve insulin sensitivity, reduce blood glucose and blood lipid levels. Its protective function may be associated with alleviating oxidative stress by increasing SOD and GSH levels, decreasing MDA and TG levels, and decreasing protein expression of GRP78and CHOP in kidney.