目的研究Ｌ精氨酸（Ｌａｒｇ）对５／６肾大部切除大鼠（ＳＮｘ）肾小管、间质αＳＭＡ表达的影响及其与细胞外基质合成、肾功能的关系。方法实验分４组：ｓｈａｍ；ｓｈａｍ＋Ｌａｒｇ；ＳＮｘ；ＳＮｘ＋Ｌａｒｇ。大鼠于术后即由饮水中给予１０ｇ·Ｌ－１Ｌａｒｇ。１ｍｏｎ后，大鼠处死，肾组织经免疫组化半定量分析肾小管间质αＳＭＡ以及ｃｏｌａｇｅｎⅢ、ｃｏｌａｇｅｎⅣ、ｆｉｂｒｏｎｅｃｔｉｎ的表达程度。用ＭａｓｏｎＴｒｉｃｈｒｏｍｅ染色切片来判断肾小管、间质损害程度。结果Ｌａｒｇ明显增加ＳＮｘ大鼠肾小管、间质αＳＭＡ及ｃｏｌａｇｅｎⅢ、ｃｏｌａｇｅｎⅣ、ｆｉｂｒｏｎｅｃｔｉｎ表达，αＳＡＭ表达程度与上述细胞外基质成分之间呈显著的正相关（Ｐ分别＜００１）。更为重要的是αＳＭＡ表达程度尚与肌酐清除率呈负相关（Ｐ＜００１），而与小管、间质损害程度呈正相关（Ｐ＜００１）。结论Ｌａｒｇ可能激活ＳＮｘ大鼠肾小管、间质成肌纤维细胞（ＭＦＢ），并促进肾脏纤维化。 Objective To investigate the effect of Largin on the expression of αSMA in renal tubule and interstitium in 5/6 subtotal nephrectomized rats (SNx) and its relationship with extracellular matrix synthesis and renal function. Methods The experiment was divided into 4 groups: sham; sham + Larg; SNx; SNx + Larg. Rats were given 10g · L-1Larg after drinking water. After 1mon, the rats were sacrificed and the renal tissues were semi-quantitatively analyzed by immunohistochemistry for αSMA of tubulointerstitium and the expression of colagen Ⅲ, colagen Ⅳ and fbr-const. MasonTrichrome staining sections to determine the extent of tubulointerstitial damage. Results Larg significantly increased the expressions ofαSMA, colagenⅢ, colagenⅣ and fibronectin in renal tubules and interstitium of SNx rats. The expression level of αSAM was positively correlated with the above extracellular matrix components (P <0.01, respectively). More importantly, αSMA expression was negatively correlated with creatinine clearance (P <001), but positively correlated with tubulointerstitial damage (P <001). Conclusion L  arg may activate SNx rat tubules, interstitial myofibroblasts (MFB), and promote renal fibrosis.