Department of Urology, Osaka University Graduate School of Medicine, Osaka, Japan.
Cell Transplant. 2010;19(12):1659-70. doi: 10.3727/096368910X516619. Epub 2010 Aug 17.
Renal ischemia-reperfusion (I/R) injury, which is unavoidable in renal transplantation, frequently influences both short- and long-term allograft survival. Despite decades of laboratory and clinical investigations, and the advent of renal replacement therapy, the overall mortality rate due to acute tubular injury has changed little. I/R-induced DNA damage results in p53 activation in proximal tubule cells (PTC), leading to their apoptosis. Therefore, we examined the therapeutic effect of temporary p53 inhibition in two rat renal transplantation models on structural and functional aspects of injury using intravital two-photon microscopy. Nephrectomized Sprague-Dawley rats received syngeneic left kidney transplantation either after 40 min of intentional warm ischemia or after combined 5-h cold and 30-min warm ischemia of the graft. Intravenously administrated siRNA for p53 (siP53) has previously been shown to be filtered and reabsorbed by proximal tubular epithelial cells following the warm ischemia/reperfusion injury in a renal clamp model. Here, we showed that it was also taken up by PTC following 5 h of cold ischemia. Compared to saline-treated recipients, treatment with siP53 resulted in conservation of renal function and significantly suppressed the I/R-induced increase in serum creatinine in both kidney transplantation models. Intravital two-photon microscopy revealed that siP53 significantly ameliorated structural and functional damage to the kidney assessed by quantification of tubular cast formation and the number of apoptotic and necrotic tubular cells and by evaluation of blood flow rate. In conclusion, systemic administration of siRNA for p53 is a promising new approach to protect kidneys from I/R injury in renal transplantation.
肾缺血再灌注（I/R）损伤在肾移植中不可避免，常影响短期和长期移植物的存活。尽管经过几十年的实验室和临床研究，以及肾脏替代治疗的出现，急性肾小管损伤导致的总体死亡率变化不大。I/R 诱导的 DNA 损伤导致近端肾小管细胞（PTC）中 p53 的激活，导致其凋亡。因此，我们使用活体双光子显微镜检查了两种大鼠肾移植模型中短暂抑制 p53 对损伤结构和功能方面的治疗效果。接受同种异体左肾移植的肾切除 Sprague-Dawley 大鼠经历 40 分钟的故意热缺血或供体冷缺血 5 小时和热缺血 30 分钟。先前的研究表明，静脉内给予 p53 的 siRNA（siP53）在肾夹模型中的热缺血/再灌注损伤后被近端肾小管上皮细胞滤过和重吸收。在这里，我们表明它在 5 小时冷缺血后也被 PTC 摄取。与盐水处理的受者相比，siP53 治疗导致两种肾移植模型中的肾功能得以维持，并且显著抑制了 I/R 诱导的血清肌酐升高。活体双光子显微镜显示，siP53 显著改善了肾小管铸型形成和凋亡和坏死肾小管细胞数量的定量评估以及血流速率评估的肾脏结构和功能损伤。总之，全身给予 p53 的 siRNA 是保护肾脏免受肾移植中 I/R 损伤的一种很有前途的新方法。
