外源性精胺对糖尿病肾病小鼠肾纤维化的影响及其机制

Effect of exogenous spermine pretreatment on alleviating renal fibrosis in diabetic nephropathy mice and its related mechanism

目的:观察外源性精胺对糖尿病肾病(DN)肾纤维化的保护作用,并探讨其机制。方法:24只雄性C57小鼠随机分为正常组(Control)、糖尿病组(T1D)和精胺预处理组(T1D+Sp,每组n=8)。一次性注射STZ(60 mg/kg)复制1型糖尿病小鼠模型,精胺预处理组在STZ注射前两周每天腹腔注射精胺(Sp,5 mg/(kg·d)),随后隔天注射精胺,第12周处死小鼠,检测血清肌酐、尿素氮判断肾功能变化,HE、PAS和Masson染色观察肾组织损伤和纤维化水平。Western blot法检测小鼠肾组织中基质金属蛋白酶(MMP-2、MMP-9)、Ⅳ型胶原(Coll-Ⅳ)蛋白的表达。结果:与Control相比,T1D组血糖(5.67±0.22 vs 28.40±0.57 mmol/L)、肌酐(14.33±1.22 vs 30.67±4.73μmol/L)、尿素氮(6.93±4.94 vs 22.00±1.04 mmol/L)明显升高(P<0.05),肾组织基底膜增厚,胶原含量明显增加,MMP-2、MMP-9和Coll-Ⅳ蛋白表达均升高(分别为0.57±0.07 vs 1.06±0.20、47.00±0.04 vs 1.29±0.09和0.42±0.16 vs 0.95±0.18,P<0.05),精胺预处理明显减轻上述变化。结论:外源性精胺预处理通过调节MMPs与胶原的平衡减轻DN小鼠的肾纤维化。

Objective: To observe the protective effects of exogenous spermine on renal fibrosis induced by diabetic nephropathy( DN) and to explore its mechanism. Methods: Twenty-four male C57 mice were randomly divided into control group,type1 diabetes group( TID) and spermine pretreatment group( TID+Sp,n = 8 in each group). TID mice were induced by STZ( 60 mg/kg),and TID+Sp mice were pretreated with spermine( 5 mg/( kg· d)) for 2 weeks before STZ injection. The mice were killed at the 12 th week. The renal function was determined by serum creatinine and urea nitrogen. HE,PAS and Masson staining were used to evaluate renal tissue injury and fibrosis. The expressions of matrix metalloproteinase( MMP-2,MMP-9) and collagen Ⅳ( Coll-Ⅳ) in the kidney of mice were detected by Western blot. Results: Compared with the control group,the blood glucose( 5.67± 0.22 vs 28.40± 0.57 mmol/L),creatinine( 14.33± 1.22 vs 30.67± 4.73 μmol/L) and urea nitrogen( 6.93±4.94 vs22.00±1.04 mmol/L) in the T1 D group were increased significantly( P< 0.05),the glomerular basement membrane was thickened,the collagen was significantly increased,the expressions of MMP-2,MMP-9 and Coll-Ⅳ protein were increased( 0.57±0.07 vs 1.06±0.20,47.00±0.04 vs 1.29±0.09 and 0.42±0.16 vs 0.95±0.18,P<0.05). Exogenous spermine significantly alleviates the above-mentioned changes. Conclusion: Exogenous spermine pretreatment could significantly alleviate renal fibrosis in diabetic mice by regulating the balance between MMPs and collagen.