巨肽受体介导的内吞作用参与庆大霉素（GM）摄取的关键作用，积累,和毒性。在这项研究中,我们研究了孟鲁司特(MLK)对megalin表达/内吞功能抗GM肾毒性的潜在影响.雄性Wistar大鼠每天分剂量施用GM(120mg/kg;i.p.),持续4小时;30mg/kg/hr;持续7天。MLK(30mg/kg/天)在之前7天口服给药,然后与GM同时给药。megalin和氯化物通道5（ClC-5）的蛋白表达；megalin内吞功能的重要调节因子之一；通过Western印迹测定。此外,用异硫氰酸荧光素(FITC-BSA)标记的牛血清白蛋白被摄取到近端肾小管上皮细胞中,以评估megalin的内吞功能.此外，肾功能生物标志物(Cr，BUN,GFR,估计了KIM-1，胱抑素C）和凋亡标志物（p-AKT1，裂解的caspase-3）。与MLK共同处理下调了ClC-5的表达，导致megalin向质膜的再循环减少，减少表达，因此，内吞功能受损，这可以通过近端肾小管上皮细胞对FITC-BSA的摄取减少来证明。凋亡执行者裂解的caspase-3的蛋白质表达显着降低，而抗凋亡p-AKT1升高。肾功能和组织学发现的改善证实了这些结果。我们的数据表明，MLK可能干扰megalin表达/内吞功能，这可能归因于ClC-5蛋白表达的下调。这最终减少了GM给药后的肾细胞凋亡并改善了肾功能，而不会影响GM的抗菌活性。因此,减少ClC-5的表达和MLK对megalin表达/内吞功能的干扰可能是抗GM肾毒性的有效策略。
Megalin receptor-mediated endocytosis participates a crucial role in gentamicin (GM) uptake, accumulation, and toxicity. In this study, we investigated the potential effects of montelukast (MLK) on megalin expression/endocytic function against GM nephrotoxicity. Male Wistar rats were administered GM (120 mg/kg; i.p.) daily in divided doses along 4 hr; 30 mg/kg/hr; for 7 days. MLK (30 mg/kg/day) was orally administered 7 days before and then concurrently with GM. The protein expressions of megalin and chloride channel-5 (ClC-5); one of the essential regulators of megalin endocytic function; were determined by Western blotting. Besides, the endocytic function of megalin was evaluated by the uptake of bovine serum albumin labeled with fluorescein isothiocyanate (FITC-BSA) into proximal tubular epithelial cells. Moreover, kidney function biomarkers (Cr, BUN, GFR, KIM-1, cystatin-C) and apoptosis markers (p-AKT1, cleaved caspase-3) were estimated. Co-treatment with MLK downregulated ClC-5 expression leading to reduced recycling of megalin to the plasma membrane, reduced expression, and so impaired endocytic function that was evidenced by reduced uptake of FITC-BSA in proximal tubular epithelial cells. The protein expression of the apoptotic executioner cleaved caspase-3 was significantly reduced, while that of the antiapoptotic p-AKT1 was elevated. These results were confirmed by the improvement of kidney functions and histological findings. Our data suggest that MLK could interfere with megalin expression/endocytic function that could be attributed to downregulation of ClC-5 protein expression. That eventually reduces renal cell apoptosis and improves kidney functions after GM administration without affecting the antibacterial activity of GM. Therefore, reduced expression of ClC-5 and interference with megalin expression/endocytic function by MLK could be an effective strategy against GM nephrotoxicity.
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