缺氧诱导因子1α对肺组织急性炎症的调控作用研究

Regulatory effect of hypoxia-inducible factor-1α on acute lung inflammation

目的研究缺氧诱导因子1α(HIF-1α)对急性肺部炎症的调控作用。方法分别用脂多糖刺激Hif-1α基因敲除(Hif-1α^+/-)小鼠及其野生型(Hif-1α^+/+)小鼠,建立急性肺损伤(ALI)模型,分别于6、12、24、48 h后留取支气管肺泡灌洗液(BALF)、血液及肺组织等,并对实验组及对照组小鼠BALF中白细胞及中性粒细胞计数,通过酶联免疫吸附试验检测各组小鼠血清中炎性因子肿瘤坏死因子α(TNF-α)及KC等的表达水平,通过HE染色评估各组小鼠肺组织及气道中性粒细胞浸润情况,通过TUNEL检测小鼠肺组织中性粒细胞凋亡情况。结果Hif-1α^+/-及Hif-1α^+/+的ALI小鼠BALF中白细胞及中性粒细胞数量均明显高于其对照组。Hif-1α^+/-实验组小鼠BALF中白细胞总数与Hif-1α^+/+实验组小鼠比较差异无统计学意义,Hif-1α^+/-实验组小鼠BALF中中性粒细胞数量明显低于Hif-1α^+/+实验组小鼠(P<0.05)。2组实验组小鼠血清TNF-α和KC水平均明显高于其对照组,Hif-1α^+/-实验组小鼠TNF-α和KC水平明显低于Hif-1α^+/+实验组小鼠。HE染色显示,Hif-1α^+/-实验组小鼠肺组织中有大量中性粒细胞浸润,其数量明显高于Hif-1α^+/+实验组小鼠。TUNEL染色进一步发现,Hif-1α^+/-实验组小鼠肺组织中存在大量凋亡的中性粒细胞,其数量明显多于Hif-1α^+/+实验组小鼠。结论HIF-1α可通过抑制中性粒细胞凋亡的机制调控急性炎症水平。

Objective To study the role of hypoxia-inducible factor-1α(HIF-1α)in regulating the acute inflammation of lung.Methods Hif-1αknockout(Hif-1α^+/-)mice and their wild-type(Hif-1α^+/+)were stimulated with lipopolysaccharide to establish acute lung injury(ALI)model,respectively.The bronohoalveolar lavage fluid(BALF),blood and lung tissue were collected at 6th,12th,24th and 48th hour after LPS treatment.The number of total leukocytes and neutrophils in BALF of ALI model group and control group were counted.The levels of inflammatory factors such as tumor necrosis factor-αand KC in the serum of each group were detected by enzyme linked immunosorbent assay.The neutrophil infiltration in airway and lung tissue of all groups was assessed by hematoxylin-eosin staining.And the neutrophil apoptosis in lung tissue of all groups was detected by TUNEL.Results The number of leukocytes and neutrophils in BALF of Hif-1α^+/-and Hif-1α^+/+ALI mice was significantly higher than that of control mice.And there was no significant difference in the number of leukocytes in BALF between Hif-1α^+/-and Hif-1α^+/+ALI mice.But compared to Hif-1α^+/+ALI mice,the number of neutrophils in BALF of Hif-1α^+/-ALI mice was significantly lower(P<0.05).The levels of TNF-αand KC in serum of both ALI model mice were significantly higher than those in control group.But the levels of TNF-αand KC in the Hif-1α^+/-ALI mice were significantly lower than those in the Hif-1α^+/+ALI mice.Hematoxylin-eosin staining indicated that there were a large amount of neutrophils infiltrating into the lung tissue and airway of Hif-1α^+/-ALI mice,which were much more than those of Hif-1α^+/+ALI mice.TUNEL staining further revealed that there were a large number of apoptotic neutrophils in the lung tissue of Hif-1α^+/-ALI mice,which were significantly more than those of Hif-1α^+/+ALI mice.Conclusions HIF-1αenhances acute lung inflammation by inhibiting neutrophil apoptosis.