目的:探讨肾病综合征(NS)患儿肾脏局部肾素 血管紧张素系统(RAS)表达与肾脏病理损害的关系，阐明儿童NS肾脏损害慢性病理进展的部分机制。方法：采用原位杂交的方法检测85例原发性NS患儿肾脏原位血管紧张素转换酶(ACE)mRNA的表达水平，评分法半定量评估肾脏的病理损害。结果：①对照组、NS患儿组肾小球内ACE mRNA表达阳性细胞百分率分别为：(3.97±1.43) %和(22.61±12.30) %，(P<0.01)；小管间质区域分别为：(19.15±5.96) %和(58.42±17.61) %，(P<0.01)。②NS患儿5种病理类型间(MCD，FSGS，MN，MPGN，MsPGN)，肾小管间质区域的ACE mRNA表达水平各组间差异无显著性意义(P>0.05)，肾小球内仅MCD组与其它各组间差异有显著性意义(P<0.01)。③按照肾脏病理损害的程度分成轻、中、重度3组，其ACE mRNA表达阳性细胞百分率分别为：(30.50±6.52) %，(45.20±11.06) %和(54.77±11.86) %，(P<0.01)。结论：在儿童NS肾脏的慢性病理进展中，肾脏局部RAS紊乱可能是重要原因之一。

OBJECTIVE: To explore the possible correlation between the expression of the renin angiotensin system (RAS) and renal pathologic lesions, and to study the mechanism of renal progressive damages in children with the nephrotic syndrome (NS).METHODS:  Eighty five children (64 boys and 21 girls) with the primary NS were involved in this study. Renal biopsies were performed in all of them. In situ hybridization was used to semiquantitate ACE mRNA expression in renals. Histopathological lesions of renals were evaluated by the method of counting score. RESULTS: ①The percentage of ACE mRNA positive cells in glomerulars of the children with NS was higher than that in normal glomerulars [( 22.61 ± 12.3 ) % vs ( 3.97 ± 1.43 ) %; P< 0.01 ]; so was it in tubulointerstitiums [( 58.42 ± 17.61 ) % vs ( 19.15 ± 5.96 ) %; P< 0.01 ]. ②No differences of ACE mRNA expression and histopathological lesions in tubulointerstitiums among the 5 different pathologic types (MCD, FSGS, MN, MPGN and MsPGN) were found. There were significant differences in ACE mRNA expression and histopathological lesions in glomerulars of the children with MCD compared with those with FSGS, MN, MPGN or MsPGN (all P< 0.01 ). ③There were significant differences in the percentage of ACE mRNA expression positive cells between the children with different degrees of kidney pathologic lesions [mild=( 30.50 ± 6.52 ) %; moderate=( 45.20 ± 11.06 ) %; severe=( 54.77 ± 11.86 ) %; P< 0.01 ].CONCLUSIONS: The RAS disorder in situ renals might be one of the important causes of progressive renal lesions in children with NS.