缺血后处理减轻肠缺血再灌注引起的肝损伤的机制研究

Mechanism of ischemic postconditioning on alleviating liver injuries after intestinal ischemia reperfusion

目的探讨缺血后处理减轻肠缺血再灌注引起的肝损伤的作用机制,为外科防治缺血再灌注损伤提供策略。方法将36只SD大鼠随机分为假手术组(SO组,仅手术显露肠系膜上动脉)、缺血再灌注组(IR组,阻断肠系膜上动脉60 min,再灌注120 min)、缺血后处理组(IP组,阻断肠系膜上动脉60 min后行3个循环的灌注30 s/阻断30 s,再持续灌注117 min),每组12只。建立模型2 h后采集各组大鼠动、静脉血及部分小肠、肝组织,检测血肿瘤坏死因子α(TNF-α)、白细胞介素10(IL-10)、丙氨酸氨基转氨酶(ALT)、天门冬氨酸氨基转移酶(AST)水平,测定血清及肝组织内丙二醛(MDA)、髓过氧化酶(MPO)水平,光学显微镜下观察小肠及肝脏病理学改变,免疫组织化学法检测肝脏组织中核因子κB p65(NF-κB p65)和缺氧诱导因子1α(HIF-1α)的表达变化。结果与SO组比较,IR组小肠、肝脏病理损伤加重,肝组织NF-κBp65和HIF-1α的表达显著升高,血清和肝组织中MDA、MPO水平及血清TNF-α、IL-10、ALT和AST水平升高;与IR组比较,IP组小肠、肝脏损伤减轻,肝组织NF-κBp65表达下降而HIF-1α的表达显著升高,血清和肝组织中MDA、MPO水平及血清TNF-α、ALT和AST水平均显著下降,血清IL-10水平增加,差异均有统计学意义(P<0.05)。结论缺血后处理可以促进抗炎因子的激活,抑制NF-κB信号通路调控的炎症级联反应,上调HIF-1α的表达,减轻小肠缺血再灌注引起的肝损伤。

Objective To investigate the mechanism of ischemic postconditioning on alleviating liver injury induced by intestinal ischemia reperfusion, and to find the prevention and treatment strategy for ischemic reperfusion injury. Methods A total of thirty-six rats were randomly divided into three groups （n=12 in each group）, Sham group（only exposing SMA）, IR group（clamping SMA for 60 min,reperfusing 120 min）, IP group （clamping SMA for 60 min, and three cycles of 30 seconds reperfusion and 30 seconds ischemia, reperfusing 117 min）. Levels of MDA and MPO in serum and liver tissues were measured after reperfusion. Levels of arterial blood TNF-α, IL-10, ALT and AST were also measured. The pathological changes of liver and small intestine were observed, and expressions of NF-κBp65 and HIF-1αprotein in liver tissues were detected by immunohistochemistry. Results Compared with the SO group, MDA and MPO levels in serum and liver tissues increased obviously in the IR group. TNF-α, IL-10, AST and ALT were increased significantly. While the intestinal and liver injuries were more serious, expressions of NF-κB p65 and HIF-1αwere increased obviously. Compared with the IR group, the intestinal and liver injuries and the expression of NF-κB p65 were decreased obviously in the IP group, the expression of HIF-1αwas increased obviously, levels of TNF-α, AST and ALT were decreased significantly, and IL-10 level was increased. MDA and MPO levels in serum and liver tissues were decreased obviously（P〈0.05）. Conculsion Ischemic postconditioning can promote the activation of inflammatory factor and the expression of HIF-1α, inhibit the inflammatory cascade reaction regulated by NF-κB signaling path, and reduce liver injury induced by intestinal ischemia reperfusion.