Losartan modulation on NOS isoforms and COX-2 expression in early renal fibrogenesis in unilateral obstruction
Losartan modulation on NOS isoforms and COX-2 expression in early renal fibrogenesis in unilateral obstruction
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DOI：
10.1111/j.1523-1755.2004.00643.x
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发表时间：
2004-06-01
影响因子：
19.6
通讯作者：
Vallés, P
中科院分区：
文献类型：
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作者：
Manucha, W;Oliveros, L;Vallés, P
背景血管紧张素II在单侧输尿管梗阻（UUO）的早期肾纤维化的发生中起着重要作用，并导致其快速进展。我们研究了血管紧张素II受体抑制剂（AT（1））氯沙坦对一氧化氮合酶（NOS）亚型和环氧合酶-2（考克斯-2）表达的影响，以及这种相互作用对UUO间质纤维化的意义，而不依赖于其对血压的影响。给大鼠灌服氯沙坦10 mg/kg/d，连续15 d，然后进行UUO 24 h或假手术对照。AT（1）受体结合和分布通过原位放射自显影研究确定。通过图像分析仪测量肾小管上皮细胞的相对体积（Vv）和mRNA水平的转化生长因子-β（TGF-β）来评价肾纤维化。采用逆转录-聚合酶链反应（RT-PCR）法测定NOS活性、NOS亚型表达及考克斯-2蛋白表达。在给予非膨胀剂量的氯沙坦后，通过接近对照组的Vv值和TGF-β mRNA表达，证实了阻塞肾脏中的肾纤维化预防。与对照组相比，未治疗的梗阻肾皮质和外髓质内条中的AT（1）受体结合密度降低，而与梗阻肾治疗组相关的同侧UUO中未观察到差异。氯沙坦治疗后，肾髓质诱导型NOS（iNOS）活性和表达增加，肾皮质神经元型NOS（nNOS）、内皮型NOS（eNOS）亚型和考克斯-2蛋白表达增加，iNOS、nNOS和考克斯-2表达下调，eNOS水平持续升高。这些结果使我们能够推断氯沙坦在单侧梗阻性肾病中的间质纤维化预防独立作用，涉及NOS亚型和考克斯-2。
Background. Angiotensin II plays a central role in the initiation of renal fibrogenesis at a very early stage leading to a rapid progression in unilateral ureteral obstruction (UUO). We examined the effect of an angiotensin II receptor inhibitor (AT(1)) losartan, independent from its effects on blood pressure, on nitric oxide synthase (NOS) isoforms and cyclooxygenase-2 (COX-2) expression and the significance of this interaction on interstitial fibrosis in UUO.Methods. Rats underwent UUO for 24 hours or control sham operation after been treated with losartan in the drinking water at 10 mg/kg/day for 15 days. AT(1) receptor binding and distribution was determined by in situ autoradiographic study. Renal fibrosis was evaluated through the relative volume of the tubulointerstitium (Vv) measured by an image analyzer, and transforming growth factor-beta (TGF-beta) at mRNA levels. NOS activity, expression of NOS isoforms by reverse transcription-polymerase chain reaction (RT-PCR) assay and COX-2 protein expression, were determined.Results. After administration of a nonhypotensive dose of losartan prevention of renal fibrogenesis was demonstrated in obstructed kidneys by means of Vv values and TGF-beta mRNA expression near controls. Decreased AT(1) receptor binding density was observed in cortex and inner stripe of the outer medulla of nontreated obstructed kidney compared to control, whereas no differences were observed in ipsilateral UUO related to obstructed kidney-treated group. The increased inducible NOS (iNOS) activity and expression of obstructed kidney medulla, increased neuronal NOS (nNOS), and endothelial NOS (eNOS) isoforms expression and COX-2 protein expression in obstructed kidney cortex showed down-regulation of iNOS, nNOS, and COX-2 with persistent levels of eNOS after losartan administration.Conclusion. These results allowed us to infer an interstitial fibrogenesis prevention independent action of losartan, involving NOS isoforms and COX-2, in unilateral obstructive nephropathy.