替普瑞酮对大鼠肾脏缺血再灌注损伤的保护作用

Geranylgeranylacetone attenuates renal ischemia reperfusion injury

目的探讨替普瑞酮对。肾脏缺血再灌注损伤的保护作用和可能机制。方法应用替普瑞酮（400mg／kg）诱导雄性SD大鼠肾脏高表达热休克蛋白72（HSP72）。以钳夹大鼠左肾蒂45min后，松开血管夹并切除右肾，建立大鼠缺血再灌注肾脏损伤模型。假手术组为打开腹腔，分离肾血管周围组织，但不钳夹血管。模型建立后24h处死大鼠，留取血清测血肌酐（Scr）和尿素氮（BUN）。肾组织石蜡切片行PAS染色，以损伤肾小管所占百分比评分法评估肾组织肾小管损伤程度。TUNEL法检测缺血再灌注损伤时肾脏细胞凋亡的发生情况。Western印迹检测X连锁凋亡抑制蛋白（XIAP）的水平。结果缺血再灌注损伤可导致急性肾衰竭，表现为血Scr、BUN明显升高（P〈0．01）；PAS染色显示外髓部有大片肾小管坏死，甚至出现基底膜裸露；TUNEL染色中肾小管上皮细胞TUNEL阳性细胞数明显增多（P〈0．01）；Western印迹结果显示，肾组织XIAP蛋白水平明显降低（P〈0．01）。替普瑞酮处理后，肾组织HSP72表达水平明显增高（P〈0．01）；缺血再灌注所致的。肾脏损伤明显改善，包括肾小管的损伤、细胞凋亡以及‘肾功能。此外，替普瑞酮可稳定。肾组织XIAP的蛋白水平（P〈0．05）。结论替普瑞酮可诱导肾脏高表达HSP72。替普瑞酮可能通过减少肾脏XIAP蛋白的降解，抑制细胞凋亡，减轻缺血再灌注的肾脏损伤。

Objective To explore the protective effects of geranylgeranylacetone（GGA） on acute renal failure rats induced by ischemia reperfusion （IR） and the possible mechanism. Methods GGA （400 mg/kg） was administered to induce overexpression of heat shock protein 72 （HSP72） in the kidney of Sprague-Dawley （SD） rats. IR model was generated by temporary clamping the left renal artery for 45 minutes followed by right nephrectomy and 24 h reperfusion. A sham-operated group was used as normal control. 24 h after reperfusion, rats were sacrificed. Blood was collected for measurement of serum creatinine （Scr） and blood urea nitrogen （ BUN ）. Paraffinembedded sections of the kidney were stained with PAS. Histological changes due to tubular damage were quantitated as tubular damage score. TUNEL assay was used to detect the apoptosis, and Western-blot was used to detect the expression of XIAP. Results After renal IR, the increased level of BUN and Scr, the tubular injury and the apoptosis of renal tubular epithelial cells were observed （P〈0.01）. At the same time, the decreased level of XIAP was observed （P〈0.01）. Compared with the control groups, the level of HSP72 expression was up-regulated in oral administration of GGA group （P〈0.05）. The expression levels of BUN and serum creatinine were significantly decreased after IR injury in pre-conditioned rats with over-expression of HSP72 （P〈 0.01 ）. Kidney morphology was better preserved in GGA group. Rats with over-expression of HSP72 also revealed reduction of apoptotic ceils by TUNEL stain and XIAP degradation by Western blot （P〈0.05）. Conclusion GGA attenuates renal IR injury at least in part through inhibiting tubular cell apoptosis by decreasing XAIP degradation and restoring XIAP protein level.