肠系膜淋巴管结扎对失血性休克大鼠肺损伤的影响

Effect of mesenteric lymph duct ligation on lung injury in hemorrhagic shock rats

目的观察结扎肠系膜淋巴管对不同时期重症失血性休克大鼠肺组织自由基、炎症介质的影响，探讨肠淋巴途径在休克大鼠急性肺损伤（ALI）中的作用。方法78只雄性Wistar大鼠被随机分为假手术组、休克组和结扎组。休克组与结扎组复制重症失血性休克模型。结扎组于休克复苏后行肠系膜淋巴管结扎术，于休克90min、液体复苏后0、1、3、6、12和24h各处死6只大鼠，制备肺组织匀浆，检测丙二醛（MDA）、超氧化物歧化酶（SOD）、肿瘤坏死因子-α（TNF—α）、白细胞介素-6（IL-6）以及髓过氧化物酶（MPO）活性。结果休克组大鼠输液复苏后各时间点肺组织匀浆MDA、TNF—α、IL-6以及MPO活性均有不同程度的升高，3～12h持续在较高水平，均显著高于假手术组，肺组织匀浆SOD活性显著低于假手术组（P〈0．05或P〈0．01）；结扎组输液复苏后3，6、12和24h肺组织匀浆MDA、TNF-α、IL-6以及MPO活性均显著低于休克组，SOD活性高于休克组（P〈0．05或P〈0．01）。结论肠系膜淋巴管结扎可干预重症失血性休克大鼠ALI，其机制与减少肺中性粒细胞扣押，降低TNF—α、IL-6、自由基释放与SOD消耗等因素有关。

Objective To observe the effect of ligation of mesenteric lymph duct on release of oxygen free radical and inflammatory mediator in lung of rat with serious hemorrhagic shock at different periods, and explore the role of intestinal lymphatic pathway on acute lung injury （ALI）. Methods Seventyeight male Wistar rats were randomly divided into the sham operation group, shock group, and ligation group. The model of serious hemorrhagic shock was reproduced in shock group, ligation group, and mesenteric lymph flow was occluded by ligating mesenteric lymph duct in ligation group after resuscitation. Eight rats were sacrificed and the lung was harvested and homogenized for the determination of malondialdehyde （MDA）, superoxide dismutase （SOD）, tumor necrosis factor - α （TNF - α）, interleukin - 6 （IL - 6） and myeloperoxidase （MPO） activity at 90 minutes after shock, 0, 1, 3, 6, 12 and 24 hours after transfusion and resuscitation. Results The contents of MDA, TNF - α, IL - 6 and MPO activity in lung homogenate of shock group were elevated after transfusion and resuscitation, and the levels were higher significantly at 3- 12 hours, than those of the sham operation group, while the acvitity of SOD was significantly lower than that of sham operation group （P〈0. 05 or P〈0.01）. The contents of MDA, TNF - α, IL - 6 and MPO in lung homogenate of ligation group at 3, 6, 12 and 24 hours after resuscitattion were significantly lower than those of shock group at the same time points, and the SOD activity were higher （P〈0.05 or P〈0. 01）. Conclusion The results demonstrate that the ligation of mesenteric lymph duct could ameliorate ALI in rats with serious hemorrhagic shock, and its mechanism might relate with reduction of sequestration of neutrophils, thus reduce the release of TNF - α and IL - 6, and also reduce the release of oxygen free radical and consumption of SOD. Therefore mesenteric lymphatics might play an important role in pathogenesis of ALI.