肠淋巴再灌注加重肠系膜上动脉闭塞性休克大鼠的脑损伤

目的:观察肠淋巴再灌注(MLR)对肠系膜上动脉闭塞性(SMAO)休克大鼠脑组织形态学以及神经递质的影响;从氧自由基、一氧化氮(NO)、中性粒细胞、膜泵、能量代谢等方面揭示其机制。方法:24只Wistar雄性大鼠均分为4组:sham组,仅麻醉与手术;MLR组,夹闭肠系膜淋巴管(ML)1h,再灌注2h;SMAO组,夹闭肠系膜上动脉(SMA)1h,再灌注2h;MLR+SMAO:夹闭ML和SMA1h,再灌注2h。再灌注2h后,选择固定位置留取脑组织,制备病理切片,观察形态学;同时制备脑组织匀浆,检测乙酰胆碱转移酶(ChAT)、乙酰胆碱酯酶(AChE)、多巴胺(DA)、去甲肾上腺素(NE)以及乳酸(LA)、丙二醛(MDA)、超氧化物歧化酶(SOD)、NO、一氧化氮合酶(NOS)、髓过氧化物酶(MPO)、细胞膜泵(ATPase)及三磷酸腺苷(ATP)水平或活性。结果:Sham与MLR组大鼠脑组织结构基本正常;SMAO组大鼠可见神经元有坏死、变性,偶见肿胀;MLR+SMAO组神经元损伤情况较SMAO组重。SMAO与MLR+SMAO组脑匀浆MDA、NO、LA含量、AChE、NOS与MPO活性均显著高于、ChAT活性与DA、NE含量显著低于MLR与sham组,且MLR+SMAO组脑匀浆MDA、NO含量、AChE、NOS与MPO活性均显著高于SMAO组;SMAO组脑匀浆SOD、Na+-K+-ATPase活性显著低于sham与MLR组、Mg2+-ATPase活性、ATP含量显著低于MLR组;MLR+SMAO组脑匀浆的SOD、Na+-K+-ATPase、Ca2+-ATPase、Mg2+-ATPase及Ca2+-Mg2+-ATPase活性均显著低于sham与MLR组,且DA含量、Ca2+-ATPase、Mg2+-ATPase及Ca2+-Mg2+-ATPase活性、ATP含量均显著低于SMAO组。结论:MLR加重SMAO休克大鼠的脑损伤、降低脑组织DA水平、增高AChE活性,其机制可能与MLR加重或增加脑组织氧自由基损伤、NO合成与释放、中性粒细胞扣押、能量代谢障碍及降低脑组织细胞膜泵活性等因素有关。

Mesenteric lymph reperfusion exacerbates brain injury in superior mesenteric artery occlusion shock rats

AIM: To observe the effect of mesenteric lymph reperfusion (MLR) on the brain morphology and neurotransmitter in rats with superior mesenteric artery occlusion (SMAO) shock, and to explore the mechanism of oxygen free radicals, nitric oxide (NO), polymorphonuclear neutrophils (PMN), membrane ATPase function and energy metabolism. METHODS: Twenty-four male Wistar rats were randomly divided into 4 groups: in sham group, the rats were given only anesthetization and operation; in MLR group, the rats were performed 1 h occlusion of mesenteric lymphatics (ML) followed by 2 h of reperfusion; in SMAO group, the rats were performed 1 h occlusion of superior mesenteric artery (SMA) followed by 2 h of reperfusion; in MLR+SMAO group, the rats were performed 1 h occlusion of SMA and ML followed by 2 h of reperfusion. After 2 h of reperfusion, the brain tissue was taken for preparing microscopic sections to observe the morphological change. At the same time, the brain tissue was homogenized for determining the choline acetyltransferase (ChAT), acetylcholine esterase (AChE), dopamine (DA), norepinephrine (NE), lactic acid (LA), malondialdehyde (MDA), superoxide dismutase (SOD), NO, nitric oxide synthase (NOS), myeloperoxidase (MPO), cell membrane ATPase and ATP. RESULTS: Morphological observation showed that the architecture of the brain was close to normal in sham and MLR groups. Necrosis, degeneration and occasional swelling were found in neuronal cells in SMAO group, and in MLR + SMAO group the injury of the neurons was more serious than that in SMAO group. The contents of MDA, NO and LA, the activities of AChE, NOS and MPO in brain homogenate in SMAO and MLR+SMAO groups were increased, the ChAT activity and DA, NE contents were reduced significantly than those in MLR and sham groups, respectively. The contents of MDA and NO, the activities of AChE, NOS and MPO in MLR+SMAO group were higher than those in SMAO group. The activities of Na+-K+-ATPase and SOD in brain homogenate in SMAO group were lower than those in sham and MLR groups, the Mg2+-ATPase activity and ATP content were lower than those in MLR group. The activities of SOD, Na+-K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and Ca2+-Mg2+-ATPase in brain homogenate in MLR+SMAO group were lower than those in sham and MLR groups, and the DA, Ca2+-ATPase, Mg2+-ATPase, Ca2+-Mg2+-ATPase and ATP were also lower than those in SMAO group. CONCLUSION: MLR exacerbates the brain injury, reduces the DA level and increases the AChE activity in SMAO shock rats, indicating that MLR enhances the brain tissue free radical injury, NO synthesis and releases, PMN detention, and decreases the activity of cell membrane ATPase, also induces the energy metabolism dysfunction.