| Objective：Through the establishment of animal model of diabetic rats induced bySTZ. Observation of endothelin-1(ET-1) and interleukin-18(IL-18) expression inrenal tissues. Possible mechanisms of losartan potassium on renal protective effects ofdiabetes, and to guide clinical medication.Methods：Select Sprague-Dawley rats (male)54, body weight185~225g.Providedby the animal experimental center of Shanxi Mdeical University and clean the feeding.The experiment was divided into3groups,18rats in each group, and SD rats wererandomly selected. Each named as follows: normal control group(NC), diabeticgroup(DM),losartan intervention group(DM-L).The control group was given normaldiet, the model group were fed on high fat diet. After6weeks, the control groupweight increased to275.6±23.8(g), model group weight increased to310.1±29.2(g).Fasting12h, NC group were given intraperitoneal injection of40mg/kgcitricacid-sodium citrate solution. The remaining rats were given intraperitionealinjection of the same dose of streptozotocin(STZ). After72hours of tail vein, randomblood glucose were greater than or equal to16.7mmol/L and more than3times weremodel success. Each group was treated after model success. Losartan potassiumgroup were given50mg.kg-1.d-1of losartan potassium saline suspension gavage. Thenormal control group and diabetic group were given equal volume of normal saline.Each group in4weeks,8weeks and12weeks,6rats from each weighing. Using thesampling method to determination of fasting blood glucose. Through the vena cavablood after anesthesia, then separation of serum and determination of serum insulinlevel. Cut the kidney filter paper and dry weight, detection of renal hypertrophy index (mg/of kidney weight g). Determination of24hours urinary albumin excretion rateby radioimmunoassay. The amount of renal tissue were fixed in10%neutral formalinand gradient ethanol dehydration, paraffin-embedded and paraffin sections. Renalhistology and morphology changes were observed under light microscope after HEstaining. The expression of IL-18and ET-1in renal tissue was detected byimmunohistochemical method. Cut12weeks old rats, quick-frozen in liquid nitrogenand storage at-70℃. Determination of IL-18and ET-1in renal tissue mRNA contentby real-time fluorescence quantitative RT-PCR (Real Time RT-PCR).Results：1. Comparison of fasting blood glucose and fasting insulin：Compared with thenormal control group the same period the diabetic group, drug intervention group ratsincreased fasting hyperglycemia, and fasting blood insulin decreased (P<0.05).2. Comparison of kidney hypertrophy index：Compared with the normal controlgroup the same period of diabetic group and the losartan intervention group ratkidney hypertrophy index was significantly increased (P<0.05). Compared with thediabetic group, the drug therapy group kidney hypertrophy index decreased, thedifference was statistically significant (P<0.05).3. Comparison of24hours urinary albumin excretion rate in rats：Comparedwith the normal control group the rats of diabetic and losartan intervention group rats24hours urinary albumin excretion rate were significantly increased (P<0.05).Compared with the diabetic group,24hours urinary albumin excretion rate of thelosartan intervention group was obviously reduced, the difference was statisticallysignificant (P<0.05).4. Comparison of the expression of ET-1and IL-18in renal tissue of each group(Immunohistochemical method)：Compared with the normal control group the sameperiod of diabetic group and intervention group IL-18and increase the expression ofET-1(P<0.05). Compared with the diabetic group, drug intervention group IL-18and the decreased expression of ET-1(P<0.05). With the passage of time, the increasedexpression of ET-1in renal tissue of diabetic group and IL-18(P<0.05); The drugtherapy group decreased expression, but the difference was not statisticallysignificant.5. Light microscopic morphology observation of renal tissue：Normal controlgroup, renal tubular morphology, structure, distribution and glomerular structure wereno obvious pathological change. The diabetic group with duration, gradually showedrenal mesangial cell proliferation and matrix increased, tubular dilation, glomerularhypertrophy. Drug intervention group with prolonged treatment, then the abovechanges gradually reduce6. Comparison of the expression of12weeks of renal tissue in ET-1rats andIL-18mRNA： Compared with the normal control group, diabetic group andintervention group ET-1and increase the expression of IL-18(P<0.05). Comparedwith the diabetic group, drug intervention group IL-18and the decreased expressionof ET-1(P<0.05).7. As revealed by Pearson analysis：The expression of ET-1and IL-18in renaltissue of diabetic rats and24hours urinary albumin excretion rate has significantpositive correlation.Conclusion：Elevated inflammatory cytokines ET-1and IL-18level in renal tissue ofdiabetic rats, at the same time with the renal pathological changes in diabetic early.Given Losartan Intervention ET-1and IL-18in renal tissue of rats was decreasedmarkedly and glomerular hypertrophy and renal tubular dilatation than beforeimprovement, pathological damage was alleviated. It shows that losartan potassiumand played a role in renal protection by inhibition of diabetic renal inflammation. |
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