肠系膜淋巴管结扎对二次打击大鼠肾小管上皮细胞凋亡的影响

Effects of mesenteric lymph duct ligation on apoptosis of renal tubule epithelial cells in rats after two - hits

目的探讨结扎肠系膜淋巴管对失血／脂多糖（LPS）二次打击致大鼠肾小管上皮细胞凋亡的拮抗作用。方法雄性Wistar大鼠45只，随机均分为结扎组、未结扎组和假手术组。用右侧颈动脉放血及致伤后6h腹腔注射LPS 4mg／kg复制失血／LPS二次打击动物模型，结扎组行肠系膜淋巴管结扎术致肠淋巴液断流。在手术创伤后24h，选取同一部位肾组织制备病理切片，用原位末端缺刻标记法（TUNEL）检测肾小管上皮细胞凋亡率，免疫组化链酶素-亲合素-生物素-过氧化物酶法（SABC）检测凋亡调控基因bcl-2和促凋亡基因bax的蛋白表达。结果二次打击后，与假手术组比较，未结扎组肾小管上皮细胞凋亡率和bax蛋白表达明显增高，bcl-2蛋白表达显著降低（P均〈0．01）；结扎组大鼠肾小管上皮细胞凋亡率、bax蛋白表达显著低于未结扎组，bcl-2蛋白表达显著高于未结扎组（P均〈0．01）。结论肠系膜淋巴管结扎可减轻失血／LPS导致的大鼠肾小管上皮细胞凋亡，其机制可能与肠系膜淋巴管结扎降低促凋亡基因bax表达、提高bcl-2表达有关。

Objective To explore the effect of mesenteric lymph duct ligation in preventing apoptosis of renal tubule epithelial cells in rats by two - hits including hemorrhage and lipopolysaccharide （LPS） challenge. Methods Forty -five Wistar rats were randomly divided into three groups： the ligation group, the non - ligation group and sham operation group. The two - hits model was established by withdrawing the blood via the right side carotid artery of rats and intragastric administration 4 mg/kg LPS 6 hours after hemorrhage, and mesenteric lymph flow was blocked by ligating mesenteric lymph duct in ligation group. Twenty-four hours after operation, kidney was harvested for pathological examination, and the apoptosis cells rate of renal tubule epithelial cells were determined by method of terminal - deoxynucleotidyl transferase mediated dUTP nick end labeling （TUNEL）, the expression of apoptosis -correlating gene bcl -2 and bax protein were determined by streptavidin-biotin complex （SABC） immunohistochemical method. Results After two-hits, the apoptosis rate and expression of bax protein of renal tubule epithelial cells in non - ligation group were significantly increased, and expression of bcl - 2 protein was significantly lower as compared with those of sham operation group （all P〈0.01）. But the apoptosis rate and expression of bax protein of renal tubule epithelial cells in ligation group were significantly lower, and expression of bcl - 2 protein was significantly increased as compared with non - ligation group （all P〈0.01）. Conclusion The results demonstrate that the ligation of mesenteric lymph duct could ameliorate the apoptosis of renal tubule epithelial cells in rats as produced by hemorrhage and LPS, and its mechanism might relate to the reduction of the down regulation of gene expression of bax protein and enhancement of the expression of bcl - 2 protein after ligation of mesenteric lymph duct.