The Protective Effect Of Simvastatin On Kidney And Its Impact On Expressions Of TLR4 And MCP-1 In Kidney Tissues Of Type 1 Diabetic

Objective：To probe the protective action of simvastatin on kidney and its influence onexpressions of TLR4 and MCP-1 in kidney tissue of type 1 diabetic rats.Methods：54 male Wistar rats, weight 180-220g, were provided by the Animal ExperimentalCenter of Shanxi Medical University. All the rats was clean. The rats were randomly divided intothree groups: normal control group (group NC)、diabetes mellitus group (group DM)、simvastatingroup (group S), and each group had eighteen rats. After fasting for 12 hours, each rat of themodel groups was injected the STZ (streptozotocin, 55mg/kg) into enterocolia, but the rat of thenormal control group was given citric acid-sodium citrate solution (55mg/kg). After 72 hours,rats of model groups were cutted off the caudal vein and were taken to test its blood sugarcontent. If the glucose concentration of caudal vein blood was more than 16.7mmol/L and theresults maintained for more than 3 times, the model of diabetic rat had been determined to besuccessfully established. The three groups were fed for one week. The rats of the group S wererespectively fed with Simvastatin(10mg/kg/d) NS MCT by gavage, while the rats of the groupNC and group DM were fed with equal volume of NS by gavage. Measuring the weight of therats for each week. The datas of blood glucose、secrum insulin and 24h urine albumin excretionrate were separately monitored at 4thweek, 8thweek and 12thweek. Cut the tail of rats andmeasured the blood glucose; anesthetized the rats, took blood from vena cava, separated theserum and measured the secrum insulin. Killing the rats by dislocation, got the kidneys.Modicums of the kidneys were frozen in liquid nitrogen and preserved at -70℃. They were usedto determine the content of TLR4 and MCP-1 mRNA of renal tissues by Real Time–PCR. Therest of renal tissues was fixed by 10% neutral formaldehyde, dehydrated by graded ethanol,embedded by paraffin, made paraffin sections. The paraffin sections were stained with HEmethod, then observed morphological changes under the light microscope. The paraffin sectionswere used to determined the content of TLR4 and MCP-1 of renal tissues byimmunohistochemistry.Results：1. The contrast of arguments (blood glucose and serum insulin) of three groups with thesame term:Compared with the group NC, the blood glucose of DM and S had a increase, whileserum insulin decreased, with statistical significance(P＜0.05).2. The contrast of 24h urinary protein of three groups:compared with the normal control group, the groups DM, S had a increase in 24h urinary protein(P＜0.05). Compared with the DM,the simvastatin treated group had a obvious decrease(P＜0.05).3. The comparison of arguments (the expression of proteins of TLR4 and MCP-1) of eachgroup with the corresponding period: In the group NC , the expression of proteins of TLR4 andMCP-1 is low.Compared with the normal control group, the groups DM, S had a increase in theexpression of proteins of TLR4 and MCP-1(P＜0.05). Compared with the DM, the simvastatintreated group had a obvious decrease(P＜0.05).4. The contrast of arguments (the expression of mRNA of TLR4 and MCP-1) in each groupat 12thweek: Compared with the normal control group, the groups DM, S had a increase in theexpression of mRNA of TLR4 and MCP-1(P＜0.05). Compared with the DM, the simvastatintreated group had a obvious decrease(P＜0.05).5. In the renal tissues of diabetic rats, the expressions of TLR4 and MCP-1 are significantlypositive correlated with the 24h urinary protein.6. The observation of renal morphology: In the NC group, the basement membrane of theglomerulus had even thickness. The glomerular capillary lumen were stenosised. There was noinfiltration of inflammatory cells in the nephric tubules and interstitial. In the DM group, theglomerular capillary lumens were blocking, and the volume of glomerulus got increased. Themesangial regions were broaden and the glomerular basement membrane increased along withlymphocytes. Epithelial cells of renal tubule were swelled and degeneration. Lymphocytes andmononuclear macrophages infiltrated in the interstitial regions. The changes of simvastatintreated group improved significantly.Conclusion: In the DM group, the content of TLR4 and MCP-1 of renal tissue remarkablyincreased and pathological changes of renal tissue emerged. In the S group, the content of TLR4and MCP-1 of renal tissue decreased and pathological changes of renal tissue relieved. Thetherapy of simvastatin may have protective effect for diabetic nephropathy.