蓝藻素通过诱导血红素氧化酶-1表达发挥对急性脓毒性肺损伤的保护作用

C-phycocyanin induces Heme oxygenase-1 expression to protect acute lung injury in septic rats

目的观察藻蓝素(C—phycocyanin,CPC)对脓毒症急性肺损伤(acute lung injury,ALI)大鼠的保护作用及分子机制。方法 75只SD大鼠随机分为对照组、模型组和3个CPC干预组。其中模型组采用盲肠结扎穿刺建立脓毒症急性肺损伤大鼠模型。CPC干预组在模型组基础上腹腔注射浓度为20、40、60 mg/kg的CPC。术后72 h获取血液及肺组织标本,检测肺湿干重比(wet-to—dry weight ratio,W/D)、支气管肺泡灌洗液中TNF—α,IL—1β和IL—6水平,以及肺组织中髓过氧化物酶(myeloperoxidase,MPO)活性,Western blot检测血红素氧合酶(heme oxygenase,HO)—1的表达以及Nrf2和NF—κB的激活。化学发光法检测超氧化物的产生,还原法检测肺组织中亚硝酸盐/硝酸盐的含量。结果 CPC处理可显著抑制脓毒症急性肺损伤大鼠肺组织的炎症反应(P<0.05),如过氧化物形成、MPO活性、白细胞渗出以及蛋白含量,以及支气管肺泡灌洗液中促炎症细胞因子和亚硝酸盐/硝酸盐的水平。同时,CPC能显著促进ALI肺组织中核转录因子Nrf2的活化和HO—1表达(P<0.05),同时也能抑制NF—κB的激活。HO—1抑制剂锡原卟啉lX(tin protoporphyrin IX,SnPP)能减轻CPC在肺损伤大鼠中的保护效应。结论 CPC对ALI大鼠的保护作用可能与诱导HO—1表达、NF—κB的激活,进而抑制炎症反应有关。

Objective To observe the protective effect and molecular mechanism of C-phycocyanin (CPC) on acute lung injury (ALI) in septic rats. Method 75 SD rats were randomly divided into control group, model group and CPC group. Cecal ligation and puncture was used to establish a septic acute lung injury rats (model group). For the CPC groups, septic acute lung injury rats were administrated by 20, 40 and 60 mg/kg CPC by intraperitoneal injection. 72 h after the operation, serum and lung tissue were obtained, the wet to dry weight ratio, the content of TNF-α、IL-6 and IL-10 in bronchoalveolar lavage fluid, the activity of myeloperoxidase (MPO) was analyzed. Expression of heme oxygenase (HO)-1,activation of nuclear factor erythroid 2-related factor 2 (Nrf 2) and nuclear factor-kappa B (NF-B) were detected by Western blot. Superoxide and Nitrite/Nitrate Level production in Lungs and bronchoalveolar lavage fluid were measured by chemiluminescence and reduction method, respectively. Results Treatment with CPC significantly inhibited septic-induced inflammatory responses including elevation of superoxide formation, myeloperoxidase activity, leucocytes and protein infiltration in lung tissues, and production of proinflammatory cytokine, and nitrite/nitrate in bronchoalveolar lavage fluid (P<0.05). In addition, CPC could activate Nrf 2 and induce HO-1 expression, and inhibit NF-B activation in ALI rats. However, blocking HO-1 activity by tin protoporphyrin IX (SnPP), an HO-1 inhibitor, markedly abolished these beneficial effects of CPC in septic-induced ALI. Conclusion The protection mechanism of CPC may be through HO-1 induction and suppressing of NF-kB-mediated inflammatory responses.