目的　研究新生鼠单侧输尿管梗阻 (UUO)对肾脏发育的影响 ,为临床评价肾积水所致肾功能损害提供依据。方法　生后 4 8h内对 70只Wister新生鼠行单侧输尿管结扎或假手术。在术后的第 1～ 2 8d切取肾脏 ,测其重量 ;取术后 14d的肾脏分别行α 平滑肌 (α SM )肌动蛋白和转化生长因子 β1(TGF β1)免疫组化染色。结果　UUO侧肾脏重量增长明显受到抑制 ,而对侧出现代偿性增长。术后 14d的切片观察到α SM肌动蛋白在梗阻侧肾脏中仍持续存在 ,而在对侧及假手术组肾中已消失。TGF β1在梗阻侧肾脏中表达增强。结论　新生鼠UUO明显影响了同侧肾脏发育 ,并使肾功能受到损害 Objective To study the effect of unilateral ureteral obstruction (UUO) on the development of kidney in neonatal rats and provide the basis for clinical evaluation of renal dysfunction caused by hydronephrosis. Methods During the 48 h after birth, 70 Wister newborn rats were unilateral ureteral ligation or sham operation. The kidneys were excised from the first day to the 28th day after operation and their weights were measured. The kidneys of the 14th day after operation were subjected to immunohistochemical staining for α-smooth muscle actin and transforming growth factor-β1 (TGFβ1). Results The weight gain of kidney in the side of UUO was obviously inhibited, while the contralateral side showed compensatory growth. Α SM actin persisted in the obstructed side of the kidney and disappeared in the contralateral and sham-operated groups of kidneys. TGF β1 is enhanced in the obstructive kidney. Conclusion Newborn rat UUO significantly affected ipsilateral kidney development and impaired renal function