肠淋巴途径在二次打击大鼠肺组织细胞凋亡中的作用

目的： 观察结扎肠系膜淋巴管对二次打击大鼠肺组织细胞凋亡、凋亡相关基因以及TNF-α、IL-6水平的影响。方法： 雄性Wistar大鼠45只，均分为结扎组、未结扎组、假手术组，以失血、LPS复制二次打击模型，结扎组行肠系膜淋巴管结扎术。在手术创伤后24 h，选择肺固定位置制作切片，TUNEL法检测细胞凋亡率，免疫组化法检测Bcl-2和Bax蛋白表达；并制备肺组织匀浆，ELISA法检测血清、肺匀浆TNF-α、IL-6。结果： 二次打击后，未结扎组肺组织细胞凋亡率、Bax表达、血清及肺匀浆TNF-α、IL-6明显高于假手术组及结扎组，Bcl-2表达显著低于假手术组及结扎组（P<0.01，P<0.05），细胞凋亡以上皮细胞为主；结扎组肺组织细胞凋亡率与假手术组比较无显著差异（P>0.05），肺组织Bcl-2表达显著增高，Bax表达显著低于假手术组（P<0.01，P<0.05）。结论： 阻断肠淋巴途径可减轻失血-LPS致大鼠肺组织细胞凋亡，其机制可能与肠系膜淋巴管结扎降低促细胞凋亡介质TNF-α、IL-6水平、提高Bcl-2表达有关。提示二次打击的肠源性淋巴液在大鼠急性肺损伤的发病过程中发挥着重要作用。

Effect of intestinal lymphatic pathway on apoptosis of lung tissue in rats by two-hit

AIM: To observe the effects of mesenteric lymph duct ligation on apoptosis of lung tissue,correlated gene expression with apoptosis and TNF-α,IL-6 contents in rats by two-hit.METHODS: 45 Wistar rats were divided into three groups: the ligation group,the non-ligation group and sham group,and the two-hit model was established by means of hemorrhage and LPS treatments.Ligating mesenteric lymph duct was conducted in ligation group.After 24 hours,the pathological sections of lung tissue were prepared for determining the apoptosis rate by TUNEL method and expressions of Bcl-2 and Bax were observed by immunohistochemical test.The lung homogenate was also prepared for determining the contents of TNF-α and IL-6 by ELISA.RESULTS: After two-hit,the apoptosis rate,Bax expression in lung tissue and contents of TNF-α and IL-6 in serum and lung homogenate in non-ligation group were increased and Bcl-2 expression was lower than that in sham group and ligation group significantly (P<0.01,P<0.05).Apoptosis rate in ligation group was no statistics difference with sham group (P>0.05),and the expression of Bcl-2 protein was increased and Bax was lower than that of sham group (P<0.01,P<0.05).CONCLUSION: Blockage of intestinal lymphatic pathway reduces the apoptosis of lung in two-hit rats,and its mechanism might relate to reduced the levels of TNF-α and IL-6 and improved the expression of Bcl-2 protein in lung by the ligation of mesenteric lymph duct.The mesenteric lymph of two-hit might play an important role in the pathogenesis of acute lung injury (ALI).