血红素加氧酶-1对小鼠海水淹溺性肺损伤的保护作用

Protective effect of heme oxygenase-1 on lung injury induced by seawater drowning in mice

目的探讨血红素加氧酶-1(heme oxygenase-1,HO-1)对小鼠海水淹溺性肺损伤的保护作用,为海水淹溺性肺损伤的治疗提供新方法.方法 48只健康成年雄性BALB/c小鼠按随机数字表法分为正常对照组(n=8)、锌原卟啉(zinc protoporphyrin,ZnPP)处理组(n=8)、海水淹溺组(3、7、15 d,n =24)、海水淹溺+ZnPP处理组(n=8).将小鼠沉浸于水深为6 cm的人工海水中28 s[(水温(25±2)℃]后取出并及时进行心肺复苏,建立小鼠海水淹溺模型.观察小鼠肺组织大体形态,检测肺湿干质量比、血清乳酸脱氢酶(lactate dehydrogenase,LDH)和超氧化物歧化酶(superoxide dismutase,SOD)水平,观察肺组织病理形态变化、肺纤维化情况、肺上皮细胞凋亡与增殖水平,检测肺组织中HO-1的蛋白表达与活性.结果海水淹溺3d和7d后肺组织出现出血,肺湿干质量比和血清LDH水平较正常对照组明显升高(P<0.05),SOD水平较正常对照组明显降低(P<0.05),肺泡腔破坏、肺泡壁增厚、红细胞与炎性细胞浸润,肺组织中HO-1的蛋白表达与活性水平较正常对照组明显升高(P<0.05),正常对照组、海水淹溺3d组和海水淹溺7d组HO-1蛋白表达分别为(0.313±0.027)、(0.604±0.092)和(0.945±0.252),HO-1活性分别为(75.0±45.6)、(220.0±109.5)和(350.0±218.9);海水淹溺15 d后,以上病理变化均明显减轻,较正常对照组无明显差异(P>0.05),肺组织中HO-1的蛋白表达(1.367±0.284)较正常对照组仍明显增加(P<0.05),而HO-1活性(125.0±50.0)较正常对照组无明显差异(P>0.05);ZnPP处理组肺组织中HO-1的蛋白表达(1.192±0.341)较海水淹溺组(1.070±0.119)无明显差异(P>0.05),而HO-1活性水平(40.0±22.4)较海水淹溺组(135.0±51.8)明显降低(P<0.05),与海水淹溺组比较,ZnPP处理组以上病理变化均明显加重(P<0.05),肺纤维化、肺上皮细胞凋亡程度增加(P<0.05),肺上皮细胞增殖减少.结论 HO-1可以通过发挥其酶活性减轻小鼠海水淹溺性肺损伤,在肺组织自身修复过程中发挥重要作用.

Objective To explore the protective effect of heme oxygenase-1 (HO-1) on lung injury induced by seawater drowning in mice,so as to provide a new strategy for the treatment of lung injury induced by seawater drowning.Methods Forty-eight healthy adult male BALB/c mice were randomly divided into the normal control group (n =8),the zinc protoporphyrin (ZnPP) treatment group(n =8),the seawater drowning group (3-d,7-d and 15-d treatment)(n =24) and the seawater drowning + ZnPP treatment group (n =8).The mice were immersed in the artificial seawater with a water depth of 6 cm and water temperature of (25 ± 2)℃ for 28 seconds.Then,the moment after the mice were taken out from the water,in-time cardio-pulmonary resuscitation was perfromed and a mouse seawater drowning model was thus established.Gross morphology of the lung tissue was observed,and lung wet/dry weight (W/D) ratio,lactate dehydrogenase (LDH) and superoxide dismutase (SOD) levels were detected accordingly.At the same time,changes in the histopathology of the pulmonary tissue,pulmonary fibrosis,apoptosis and proliferation of lung epithelial cells were also observed.HO-1 protein expression and activity in the lung tissue were measured as well.Results Three and 7 days after seawater drowning,there was pulmonary hemorrhage in the lung tissue.The lung wet/dry ratio and serum LDH level significantly increased,as compared with those of the normal control group (P < 0.05),and the SOD level significantly decreased,as compared with that of the normal control group (P < 0.05).Furthermore,alveolar cavity was damaged,alveolar wall thickened,red blood cells and inflammatory cells were infiltrated.HO-1 protein expression level and activity in the lung tissue significantly increased as compared with those of the normal control group (P < 0.05).The expression levels of HO-1 protein in the normal control group,the 3-d and 7-d seawater drowning groups were respectively (0.313 ± 0.027),(0.604 ± 0.092) and (0.945 ± 0.252),and HO-1 activity in these groups were respectively (75.0 ± 45.6),(220.0 ± 109.5) and (350.0 ± 218.9).Fifteen days after seawater drowning,the above pathological changes in the groups significantly alleviated,and no significant differences could be noted,as compared with those of the normal control group (P >0.05).The HO-1 protein expression in the lung tissue was (1.367 ±0.284),which was significantly higher as compared with that of the normal control group (P < 0.05),while HO-1 activity was (125.0 ±50.0),and there were no significant differences,as compared with that of the normal control group (P >0.05).Seven days after seawater drowning,the expression of HO-1 protein in the lung tissue for the ZnPP treatment group was (1.192 ± 0.341),which displayed no significant differences from that of the seawater drowning group (1.070 ± 0.119)(P > 0.05),while HO-1 activity was (40.0 ± 22.4),which was significantly lower than that of the seawater drowning group (135.0 ± 51.8)(P < 0.05).As compared with the seawater drowning group,pathological changes in the ZnPP treatment group all obviously worsened 7 days after seawater drowning (P > 0.05),the pulmonary fibrosis and lung epithelial cell apoptosis increased (P < 0.05),and lung epithelial cell proliferation decreased.Conclusion HO-1 could alleviate lung injury induced by seawater drowning through the access of enzyme activity,and it might play an important role in the the course of lung self-repair.