Toll样受体4在糖尿病肾病患者肾组织中的表达及厄贝沙坦的干预作用

Expression of Toll-like Receptor 4 in Renal Tissue of Patients with Diabetic Nephropathy and Effects of Irbesartan

目的探讨Toll样受体4(TLR4)信号通路与糖尿病肾病(DN)的关系及使用血管紧张素受体拮抗剂(ARB)干预对TLR4信号通路的影响,探讨其肾脏保护机制。方法研究对象为2012年7月至2014年6月在南昌大学第一附属医院肾内科住院的糖尿病肾病患者,使用ARB厄贝沙坦治疗的为ARB组,未使用的患者为DN组,泌尿外科行肾脏切除的患者为对照组(C组),收集各组患者血液检测血肌酐(Scr)、血尿素氮(BUN),留取尿液测24 h尿蛋白定量等临床指标;病理常规染色和特殊染色观察各组患者肾组织病理变化;免疫组化法检测各组患者肾组织TLR4及相关炎症因子表达水平。结果 DN组:血肌酐(235.8±21.8)μmol/L、血尿素氮(13.7±4.9)mmol/L、24 h尿蛋白定量(4.41±1.12)g;ARB组:血肌酐(217.7±22.7)μmol/L、血尿素氮(8.9±1.5)mmol/L、24 h尿蛋白定量(3.25±0.89)g;C组:血肌酐(51.6±29.6)μmol/L、血尿素氮(4.6±1.5)mmol/L、24 h尿蛋白定量(0.11±0.04)g;DN组均高于ARB组及C组(均P<0.05)。病理染色结果显示:C组肾小球和肾小管未见明显变化;ARB组肾小球毛细血管球肥大,基底膜轻度增厚,系膜轻度增生,肾小管上皮细胞显示空泡和颗粒变性,肾间质和小动脉无明显病变;DN组肾小球毛细血管基底膜弥漫性增厚,系膜基质增生甚至有些肾小球的系膜基质重度增生,形成结节状硬化。免疫组化结果显示:TLR4、髓样分化因子88(MyD88)、核因子-κB(NF-κB)、单核细胞趋化因子(MCP-1)、肿瘤坏死因子(TNF-α)的表达,DN组较ARB、C组表达均增高(均P<0.05),ARB组较C组表达增高(均P<0.05)。TLR4与MyD88、NF-κB、MCP-1、TNF-α的表达量呈正相关(r分别为0.940、0.963、0.934、0.929,均P<0.05)。结论糖尿病肾病患者体内TLR4信号通路被激活,使用厄贝沙坦可阻断TLR4信号通路,减轻患者肾功能损害,提示阻断TLR4信号通路可能成为治疗糖尿病肾病的新方法。

Objective To investigate the role of toll-like receptor 4（TLR4） signaling in patients of diabetic nephropathy（DN）and the effects of angiotension receptor blocker（ARB）on the expression of TLR4,revealing novel mechanism of inflammatory response in DN and to explore non-hemodynamic effects of ARB on renal protection.Methods Diabetic nephropathy patients were enrolled from Division of Nephrology of the First Affiliated Hospital of Nanchang University from July 2012 to June2014.The patients treated with ARB served as irbesartan group,patients who did not use irbesartan were designated to DN group.The patients with renal resection from Urology Department served as control groupCC group）.Blood serum creatinine（SCr）,urea nitrogen（BUN）and 24 h total protein of urine were measured Pathological routine staining and special staining were used to observe kidney pathological changes of each group patients.The expression of TLR4 and the related inflammation factors were detected by immunohistochemistry.Results The pathological biopsy results showed that in C group,renal glomerular and tubular mesenchyme was not changed obviously;while in DN group,the glomerular capillary basement membrane was diffusely thickened,mesangial matrix was hyperplastic and even some were severely hyperplastic to form tuberous sclerosis.Compared with DN group,the glomerular basement membrane in ARB group was mildly thickened,mesangial was hyperplastic,renal mesenchyme and small artery had no obvious pathological changes.Blood Scr,BUN,and urine protein in the DN group was higher than those in the ARB group and C group（all P〈0.05）.The results of immunohistochemistry showed that the levels of TLR4,MyD88,NF-κB,MCP-1,TNF-α of DN group were higher than those of ARB group and C group（all P〈0.05）,and those were higher in the ARB group than in C group（all P〈0.05）.The expression level of TLR4 was positively correlated with the levels of MyD88 and NF-KB（r=0.940,0.963,P〈0.05）,and also positively correlated with the levels of MCP-1 and TNF-α（r=0.934,0.929,P〈0.05）.Conclusion TLR4 signaling pathway is activated in DN patients and irbesartan can block the TLR4 signaling and alleviate impairment of renal function in DN patients,indicating that blocking the TLR4 signaling pathway may be a new target for the treatment of DN.