Bautista-García Pablo, Sánchez-Lozada Laura Gabriela, Cristóbal-García Magdalena, Tapia Edilia, Soto Virgilia, Avila-Casado Ma Carmen, Márquez-Velasco Ricardo, Bojalil Rafael, Franco Martha, Herrera-Acosta Jaime
Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano 1, 14080-Mexico City, Mexico.
Nephrol Dial Transplant. 2006 Nov;21(11):3074-81. doi: 10.1093/ndt/gfl444. Epub 2006 Aug 25.
Chronic renal damage is associated with inflammatory infiltration, fibrosis and vascular lesion, coupled with increased expression of cyclo-oxygenase 2 (COX-2) and transforming growth factor-beta1 (TGF-beta1). However, the role of inducible nitric oxide synthase (NOS-2) is still controversial. Thus, we studied the contribution of NOS-2 to the expression levels of COX-2 and TGF-beta1, as well as the structural renal injury in rats with subtotal renal ablation (5/6 Nx).
Four groups of rats were studied: sham, 5/6 Nx, 5/6 Nx+aminoguanidine (AG) and 5/6 NX+L-NIL (L-N6-iminoethyl-lysine). Systolic blood pressure (SBP), proteinuria and creatinine (Cr) clearance were measured. NOS-2, COX-2 and TGF-beta1 gene expression was determined by real-time reverse transcription-polymerase-chain reaction. Protein expression was evaluated by western blot and ELISA (TGF-beta1). Immunohistochemistry and morphometry were performed for NOS-2, microvascular thickening and fibrosis.
Systemic hypertension and marked proteinuria, increased expression of NOS-2, COX-2 and TGF-beta1, thickening of arteriolar wall and tubulointerstitial fibrosis were produced in 5/6 Nx rats. Chronic inhibition of NOS-2 did not prevent arterial hypertension or the fall in Cr clearance, but partially reduced proteinuria. Nevertheless, AG and L-NIL preserved arteriolar morphology and the administration of both selective inhibitors of inducible NOS (AG and L-NIL) prevented NOS-2 overexpression.
This study shows that NOS-2 was markedly enhanced in renal tissue of 5/6 Nx rats. Moreover, treatment with AG and L-NIL prevented the morpho-functional changes induced by subtotal renal ablation, despite persistence of systemic hypertension, suggesting that high concentrations of nitric oxide produced by NOS-2 could act as a positive modulator of the proinflammatory and profibrotic pathways involved in the progression of renal disease.
慢性肾损伤与炎症浸润、纤维化及血管病变相关，同时伴有环氧化酶2（COX - 2）和转化生长因子β1（TGF - β1）表达增加。然而，诱导型一氧化氮合酶（NOS - 2）的作用仍存在争议。因此，我们研究了NOS - 2对COX - 2和TGF - β1表达水平的影响，以及对肾次全切除（5/6 Nx）大鼠肾脏结构损伤的影响。
研究了四组大鼠：假手术组、5/6 Nx组、5/6 Nx + 氨基胍（AG）组和5/6 NX + L - NIL（L - N6 - 亚氨基乙基 - 赖氨酸）组。测量收缩压（SBP）、蛋白尿和肌酐（Cr）清除率。通过实时逆转录 - 聚合酶链反应测定NOS - 2、COX - ²和TGF - β1基因表达。通过蛋白质印迹法和酶联免疫吸附测定法（ELISA）（检测TGF - β1）评估蛋白质表达。对NOS - 2、微血管增厚和纤维化进行免疫组织化学和形态计量学分析。
5/6 Nx大鼠出现全身性高血压和明显蛋白尿，NOS - 2、COX - 2和TGF - β1表达增加，小动脉壁增厚和肾小管间质纤维化。慢性抑制NOS - 2不能预防动脉高血压或Cr清除率下降，但可部分降低蛋白尿。然而，AG和L - NIL可保持小动脉形态，两种诱导型一氧化氮合酶选择性抑制剂（AG和L - NIL）的给药可防止NOS - 2过度表达。
本研究表明，5/6 Nx大鼠肾组织中NOS - 2明显增强。此外，尽管全身性高血压持续存在，但AG和L - NIL治疗可预防肾次全切除诱导的形态功能变化，提示NOS - 2产生的高浓度一氧化氮可能作为参与肾脏疾病进展的促炎和促纤维化途径的正调节因子。
