缺氧诱导因子-1α在鼠肺缺血再灌注损伤中的表达与意义

The Expression and Significance of Hypoxia Inducible Factor-1α on Lung Ischemia/Reperfusion Injury in Rats

目的:探讨缺氧诱导因子-1α(hypoxia inducible factor-1 alpha,HIF-1α)对鼠肺缺血再灌注损伤是否具有保护作用及可能的机制。方法:选择体重250～350 g的健康雄性SD大鼠72只,随机分为3组,缺血再灌注组、二甲基乙二酰基甘氨酸(DMOG)组、假手术组,每组24只。缺血再灌注组:建立左肺缺血和再灌注动物模型:在肺充气状态下用无损伤动脉钳夹闭左侧肺门,阻断45 min后松开动脉夹,形成再灌注;DMOG组:在缺血和再灌注动物模型建立前24 h进行腹腔内注射DMOG 20μg/g;假手术组:仅行左侧开胸,不行缺血再灌注处理。缺血再灌注组与DMOG组于再灌注1 h、3 h、6 h、12h后颈动脉放血处死大鼠,假手术组于开胸后1 h、3 h、6 h、12 h颈动脉放血处死大鼠,取左肺上半部制成匀浆,硫代巴比妥酸比色法检测丙二醛含量、黄嘌呤氧化酶法检测超氧化物歧化酶活力,酶联免疫吸附法测定匀浆内白细胞介素-8含量,下半部通过免疫组化法行HIF-1α蛋白表达的观察与光镜下苏木素伊红(HE)染色后肺组织病理学改变的观察。结果:HIF-1α蛋白主要表达于肺泡上皮细胞的胞核或胞浆,与假手术组比较,缺血再灌注组、DMOG组各时间点HIF-1α蛋白的表达增强,DMOG组较缺血再灌注组各时间点HIF-1α蛋白的表达增强;缺血再灌注组、DMOG组在再灌注后3 h、6 h、12 h(缺血再灌注组12 h除外)较1 h HIF-1α蛋白的表达增强,差异有统计学意义(P<0.05或P<0.01)。与假手术组比较,缺血再灌注组、DMOG组各时间点白细胞介素-8(除DMOG组1 h外)、丙二醛含量均升高,而超氧化物歧化酶活力降低;DMOG组较缺血再灌注组各时间点白细胞介素-8、丙二醛含量均降低,而超氧化物歧化酶活力升高;缺血再灌注组、DMOG组在再灌注后3 h、6 h、12 h较1 h:白细胞介素-8含量(除DMOG组3 h外)升高,丙二醛含量(除缺血再灌注组、DMOG组12 h外)升高,超氧化物歧化酶活力降低,差异均有统计学意义(P<0.05或P<0.01)。光镜下DMOG组肺组织炎性渗出较缺血再灌注组减轻。结论:HIF-1α通过降低肺组织中丙二醛、白细胞介素-8含量,增强肺组织中超氧化物歧化酶活力,减轻肺内毛细血管充血及炎性细胞浸润,对大鼠肺缺血与再灌注损伤发挥保护作用。

Objective： To investigate the protective effect of hypoxia inducible factor-1 a （HIF-1a） on lung ischemia/reperfusion （I/R） injury with its possible mechanism in rats. Methods： A total of 72 male SD rats were randomly divided into three groups, n = 24 in each group. I/R group, the animal model was established by left hilum pulmonis clamping, Dimethyloxalylglycine （DMOG） group,the rats were intraperitoneal injected with DMOG before I/R, and Sham operation group. Each group were further divided into 4 subgroups after I/R or operation at 1,3,6 and 12 hours respectively,n=6 in each subgroup. The left lung tissue was taken and examined at the above mentioned 4 time points for the content of malondialdehyde, the level of interleukin-8 （IL-8） and the activity of erythrocuprein. HIF-1a expression was measured by immunohistochemistry, the pathological change of the lung tissue was also examined. Results： The protein expression of HIF-1a was mainly observed in lung endochylemas and nucleus. Compared with Sham operation group, HIF-1 a protein expression was higher in both I/R group and DMOG group at different time points, and HIF-1 a expression in DMOG group was even higher than I/R group,P〈0. 05 or P〈0. 01. Compared with Sham operation group,the levels of malondialdehyde and IL-8 were increased and the activity of erythrocuprein was decreased in both I/R group and DMOG group at different time points,P〈0.05 or P〈0. 01. Compared with I/R group, DMOG group had lower malondialdehyde, IL-8 and higher activity of erythrocuprein. The inflammatory cell infiltration was reduced in DMOG group than that in I/R group. Conclusion： HIF-1a may reduce the inflammatory cell infiltration and therefore, protect the lung ischemia/reperfusion injury in rats.