肾脏中性粒细胞明胶酶相关脂质运载蛋白的表达与肝硬化时肾功能的关系

Correlation between kidney expression of neutrophil gelatinase-associated lipocalin and renal function impairment in liver cirrhosis

目的观察肝硬化模型中肾脏中性粒细胞明胶酶相关脂质运载蛋白(NGAL)表达与肾功能受损之间的关系。方法选择60只SD雄性大鼠,其中27大鼠在建模过程中死亡,5只SD雄性大鼠作为空白对照,28只SD雄性大鼠经持续服用四氯化碳诱导形成肝硬化腹水模型,按照免疫组化检测肾脏表达NGAL的强度和阳性细胞数建立不同级别组:低度表达组,中度表达组,高度表达组,极高表达组。Western blot测定各组NGAL的表达,并通过检测蛋白条带的光密度值进行半定量分析。通过全自动生化分析仪测定肌酐(Cr)及尿素氮(BUN)。结果 28只大鼠出现肝硬化腹水,Western blot半定量检测发现各组之间差异有统计学意义(P<0.05),极高表达组表达量最高,而高度表达组、中度表达组、低度表达组表达量依次降低;肾脏NGAL的表达越强,大鼠血中BUN、Cr升高的越多,且差异有统计学意义(P<0.05)。肾脏NGAL表达主要分布在近曲肾小管及远端肾单位。结论在肝硬化腹水肾脏功能损伤时,肾脏NGAL主要分布于近曲肾小管及远端肾单位,且其表达提示肾脏损伤程度。

Objective To observe the relationship between kidney expression of neutrophil gelatinase-associated lipocalin （NGAL） and renal function in a rat liver cirrhosis model.Methods A total of 60 male Sprague Dawley （SD）rats were included in this experiment.27 rats were died during the process of model building,5 male SD rats were used as control,28 male SD rats were induced into liver cirrhosis with ascites through periodic carbon tetrachloride intragastric administration.Different groups such as slight staining group,moderate staining group,intense staining group,highly intense staining group were divided according to the NGAL expression intensity and NGAL positive cell number detected by immunohistochemistry.Then the protein expression of NGAL was further examined by Western blot and semi-quantified by densitometry.Automatic biochemistry analyzer was employed to measure blood urea nitrogen （BUN）and serum Creatinine （Cr）.Results 28 animals with cirrhosis developed ascites.Western blot analysis revealed that there were significant differences among those different groups （P ＜ 0.05）.The expression of NGAL in highly intense staining group was highest.The expression of NGAL was stepwise decreased from intense staining group to moderate staining group and slight staining group.BUN,Cr levels in blood elevated as NGAL expression in kidney increased （P ＜0.05）.Furthermore,NGAL distributed primarily in proximal tubules and distal nephron segments in these groups.Conclusion In the rat liver cirrhosis model with impaired renal function,NGAL primarily distributes in proximal tubules and distal nephron segments.The NGAL staining intensity is correlated with the degree of renal function impairment.