胰岛素联合贝那普利下调高迁移率核小体蛋白1/Toll样受体4的表达改善糖尿病肾组织炎症的研究

Improvement of insulin combined with Benazepril on renal tissue inflammation in diabetic mice through downregulating HMGN1/TLR4 expression

目的探讨胰岛素联合贝那普利对糖尿病小鼠肾脏病变的影响及其相关机制。方法 8周龄C57BL/6健康小鼠25只,选取5只作为正常对照组(NC组),余20只腹腔注射150mg/kg的STZ诱导建立T1DM模型后随机平均分为单纯糖尿病(DM)组、胰岛素治疗(INS)组、贝那普利治疗(BEN)组及胰岛素联合贝那普利治疗(INS+BEN)组。8周后检测各组血糖、肾重/体重(KW/BW)和尿白蛋白/肌酐比值(UACR),观察肾组织形态学变化,检测肾组织高迁移率核小体蛋白1(HMGN1)、Toll样受体4(TLR4)的表达。结果与NC组比较,DM组血糖、KW/BW及UACR升高[(8.571±0.701)vs(24.280±1.944)mmol/L,(1.438±0.022)vs(1.698±0.088),(97.691±10.680)vs(697.673±168.781)μg/mg,P<0.01],可见肾小管间质炎性细胞浸润,系膜扩增改变,HMGN1和TLR4的mRNA、蛋白表达增加;与DM组比较,INS+BEN组KW/BW无明显改变[(1.698±0.088)vs(1.489±0.065),P>0.05],而血糖和UACR下降[(24.280±1.944)vs(12.150±1.150)mmol/L,(697.673±168.781)vs(148.570±28.935)μg/mg,P<0.05],肾脏组织病变减轻,HMGN1和TLR4的mRNA、蛋白表达降低,且上述变化较BEN组、INS组改善明显。Pearson相关性分析显示,HMGN1和TLR4在肾组织中的表达呈正相关,且两者表达量的变化与肾脏系膜指数也呈正相关。结论胰岛素联合贝那普利可改善STZ糖尿病小鼠的肾脏病变,其机制可能与降低HMGN1和TLR4的表达有关。

Objective To observe the effects of Benazepril combined with insulin on nephropathy in diabetic mice and to explore its related mechanism. Methods Among 25 healthy 8-week old C57BL/6J mice, 5 were randomly selected as normal control group （NC）, the rest were established as type 1 diabetes mellitus （T1DM）models by a single peritoneal injection of 150 mg/kg streptozocin （STZ）. T1DM mice were divided randomly into four groups： 5 without treatment （DM group）, 5 treated with insulin （INS group）,5 treated with Benazepril （BEN group） and 5 treated with insulin and Benazepril （INS＋BEN group）. After 8 weeks, blood glucose, kidney/body weight （KW/BW） and urine albumin/creatinine ratio （UACR） were measured. Morphology in kidney was observed. The expression levels of high-mobility group nucleosome-binding protein 1 （HMGN1） and Toll-like receptor 4 （TLR4） were determined. Results Compared with NC group, blood glucose, KW/BW and UACR were significantly increased in DM group [（8. 571＋_0. 701） vs （24. 280＋_1. 944） retool/L, （1. 438-~0. 022） vs （1. 698_＋0. 088）, （97. 691 _＋ 10. 680） vs （697. 673!168. 781） /~g/mg,P^0.01 ],along with interstitial inflammatory cell infiltrate and mesangial matrix expansion. Compared with DM group, histopathologic changes were alleviated and the protein and mRNA expression levels of HMGN1 and TLR4 were lower in the INS＋BEN group,while the KW/BWs were maintained at high levels [ （1. 698± 0. 088） vs （1. 489 ± 0.06）, P〉0.05 ], excluding reduced blood glucose level and UACR[ （24. 280±1. 944） vs （12. 150±1. 150） mmol/L, （697. 673± 168. 781） vs （148. 570±328. 935） μg/mg,P〈0.05 ]. All the above changes are more markedly in INS＋ BEN group than INS group or BEN group. Pearson correlation analysis showed that the renal expression levels of HMGNI and TLR4 were significantly positively correlated and both positively correlated with renal mesangial index. Conclusion Insulin combined with Benazepril may alleviate the nephropathy in STZ-induced diabetic mice by down-regulating the expressions of HMGN1 and TLR4.