肿瘤坏死因子-α增强肝肾综合征时肾脏I型1,4,5-三磷酸肌醇受体表达

Tumor necrosis factor-α enhances the expression of type 1 inositol 1,4,5-triphosphate receptors

目的:通过观察TNF-α对肾组织中Ⅰ型IP3R表达的影响来探讨肝肾综合征的发病机制.方法:制备大鼠离体肾灌注模型,随机分成对照组(A组)、肝素处理组(B组)、TNF-α处理组(C组),留取的标本应用免疫组织化学技术、Westernblot及实时定量PCR检测肾组织Ⅰ型IP3R蛋白的定位、表达及mRNA的变化.结果:Ⅰ型IP3R主要分布于肾小球系膜细胞和血管平滑肌细胞的胞质内.免疫组化结果显示,C组与A组相比棕褐色颗粒着色的阳性细胞明显增多,有显著性差异(U=2.26,P<0.05);B组与A组相比阳性染色细胞无明显减少(P>0.05);Western blot结果与免疫组织化学结果相一致:C组与A组相比Ⅰ型IP3R蛋白表达水平明显增高,有显著性差异(1.89±0.11vs0.55±0.03,P<0.05);B组与A组相比无显著性差异(P>0.05);实时定量PCR结果显示:C组与A组相比Ⅰ型IP3R mRNA的表达水平明显增高,有显著性差异(7.99±0.12vs1.00±0.05,P<0.05);B组与A组相比无显著性差异(P>0.05).结论:TNF-α可增强肾小球系膜细胞和血管平滑肌细胞Ⅰ型IP3R蛋白的表达,且Ⅰ型IP3R mRNA也呈增加趋势.

AIM： To clarify the mechanisms of renal vasoconstriction in hepatorenal syndrome （HRS） by investigating the effect of tumor necrosis actor-α （TNF-α on the expression of type 1 inositol 1,4,5-triphosphate receptors （IP3R） in renal tissues. METHODS： Ex vivo perfused rat kidney model was used in this study. Male Wistar rats were randomly divided into 3 groups： control group （group A）, heparin （10 mg/L） treatment group （group B）, and TNF-α （1 μg/L） treatment group （group C）. After perfusion, immunohistochemical staining, Western blot, and real-time quantitative polymerase chain reaction （RTQ-PCR） were used to detect the distribution and expression of type 1 IP3R in renal tissues. RESULTS： Immunohistochemical staining showed that type 1 IP3R protein was localized at the plasma region of glomerular mesangial cells and vascular smooth muscle cells in rat kidney, and the number of positive cells was significantly higher in group C than that in group A （U = 2.26, P 〈 0.05）. However, there was no marked difference between group A and B （P 〉 0.05）. Western blot demonstrated a consistent result with immunohistochemistry did. The protein expression of type 1 IP3R was significant higher in group C than that in group A （1.89 ± 0.11 vs 0.55 ± 0.03, P 〈 0.05）, and there was no marked difference between group A and B （P 〉 0.05）. RTQPCR showed that the mRNA expression of type 1 IP3R was dramatically increased in group C as compared with that in group A （7.99 ± 0.12 vs 1.00 ± 0.05, P 〈 0.05）, and no marked difference exists between group A and B （P 〉 0.05）. CONCLUSION： TNF-α can enhance the protein and mRNA expression of type1 IP3R in glomerular mesangial cells and vascular smooth muscle cells from kidney.