白介素33在百草枯诱导小鼠急性肺损伤中的作用机制研究

Role of interleukin-33 in paraquat-induced acute lung injury

目的探讨白介素33(IL-33)在百草枯(PQ)染毒小鼠急性肺损伤(ALI)模型中的表达及作用。方法 25只SPF级雌性BALB/c小鼠平均分为正常对照组,PQ损伤6、12、24、48 h组。腹腔注射PQ(30 mg/kg)建立小鼠ALI模型并于各时间点处死取材。评价肺组织病理变化和炎症细胞浸润;观察血清白介素1β(IL-1β)、IL-2、IL-6、肿瘤坏死因子α(TNF-α)和肺组织髓过氧化物酶(MPO)水平变化;RTPCR、免疫组化和Western blot分别检测组织中IL-33 mRNA和蛋白表达水平变化。分析IL-33与病理损伤和炎症指标关联性以明确IL-33在调解内源性细胞因子及在ALI中的作用。结果与正常对照组相比,PQ损伤后小鼠肺组织弥漫性损伤伴有严重水肿及大量炎症细胞浸润,促炎细胞因子IL-1β、IL-6、TNF-α、MPO明显升高,抑炎细胞因子IL-2明显下调(P<0.05);PQ损伤后IL-33在mRNA和蛋白表达水平均显著下调(P<0.05)。关联性分析显示IL-33与病理损伤指标,IL-1β、IL-6、TNF-α、MPO均呈明显负相关(P<0.05),与IL-2呈正相关趋势,但差异无统计学意义。结论 IL-33在PQ诱导小鼠ALI中表达水平下降,提示可能在调解内源性炎症因子平衡中发挥重要作用,可为临床干预和治疗ALI的新靶点。

Objective To evaluate role of interleukin 33 （IL-33） in paraquat （PQ）-induced acute lung injury （ALI）.Methods 25 female BALB/c mice were randomly divided into five group：control group （injection with physiological saline）,PQ 6 h group [6 h after paraquat poisoning（30 mg/kg）],PQ 12 h group,PQ 24 h group and PQ 48 h group.All mice were killed at indicated time after PQ poisoning.The lung tissue was weighted by the ratio of （lung/mouse） weight,and lung injury and neutrophil infiltration were observed by hematoxylin-eosin staining and immunohistochemistry respectively.Besides,interleukin-1β （IL-1β）,IL-2,IL-6,tumor necrosis factor α （TNF-ot） in serum and myeloperoxidase （MPO） in lung tissue were determined by relevant ELISA kits.Furthermore,the IL-33 mRNA in lung tissue was detected by quantitative real time PCR,while the IL-33 protein was detected using immunohistochemistry and Western blot assay.Spearman＇ s rank correlation between IL-33 and other variables or severity of lung impairment were analyzed simultaneously.Results There were marked histological lesions and neutrophils infiltration in lung tissue and a significant increase of IL-1β,IL-6,TNF-o and MPO in serum after PQ poisoning at indicated time,while a lower level of IL-33 and IL-2 were found in serum compare with control group （P ＜ 0.05）.There was a negative correlation between IL-33 and lung damage scores,relative lung weight,IL-1β,IL-6,TNF-o and MPO （P ＜ 0.05）.No significant correlation was found between IL-33 and IL-2.Conclusion Our study indicates that endogenous IL-33 fluctuation plays a crucial role in PQ-induced acute lung injury,which represents a potential target for clinical intervention during PQ-induced ALI.