PM2.5致大鼠肺损伤模型中肺巨噬细胞NLRP3 炎性小体活化研究

摘要： 目的 探讨肺巨噬细胞NLRP3炎性小体活化在大气细颗粒物 （PM2.5） 所致肺炎症损伤中的作用。方法 采用中流量采样器收集PM2.5颗粒物制成混悬液, 经气管滴注给予高、 中、 低剂量 （分别为15、 10、 5 mg/kg） 制成大鼠肺损伤模型, 3 d后麻醉动物进行肺泡灌洗, 收集支气管肺泡灌洗液 （BALF） 中的巨噬细胞, 中性红法测定其吞噬功能, 并采用免疫荧光双染色观察肺巨噬细胞内NLRP3的表达; 处死大鼠解剖取肺组织, HE染色观察肺损伤严重程度并评分, 免疫组化法检测肺组织NLRP3表达, ELISA法测定肺组织内IL-18、 IL-1β及Caspase-1的表达情况。结果 大鼠经气管滴注PM2.5染毒后, BALF内巨噬细胞吞噬功能下降。实验组大鼠肺损伤明显, 表现为间质性肺炎; 肺泡间隔明显增宽, 部分肺泡壁断裂, 尤以高剂量组表现明显; 各实验组大鼠的肺组织病理学评分均明显高于对照组 （均 P＜0.05）。低、 中、 高剂量组大鼠肺组织内NLRP3表达均高于对照组。肺组织内IL-18、 IL-1β及Caspase-1的表达不同程度上调。结论 大鼠气管滴注PM2.5引起的肺损伤和炎症反应与肺巨噬细胞内NLRP3炎症小体的活化有关。

Study on NLRP3 inflammasome activation of alveolar macrophages in rat model of lung injury induced by PM2.5

Abstract: Objective To study the role of NLRP3 inflammasome activation of alveolar macrophages in lung injury induced by PM2.5. Methods Rats were made into the lung injury model by intratracheal instillation of high, medium and low doses (15, 10, 5 mg /kg respectively) of PM2.5 suspension collected by medium flow atmospheric sampler. Three days later, the bronchoalveolar lavage was performed, and the phagocytic function of the macrophages in bronchoalveolar lavage fluid (BALF) was measured by neutral red method. And the expression of NLRP3 in lung macrophages was observed by double-immunofluorescent labeling method. The rats were sacrificed, and the lungs were dissected to observe the severity of lung injury by HE staining. The expression of NLRP3 was observed by immunohistochemistry staining. The expressions of IL-18, IL-1β and Caspase-1 in lung tissues were detected by ELISA method. Results By intratracheal instillation of PM2.5, the phagocytic function of macrophages in BALF decreased. And lung injuries of the rats were obvious, manifesting as interstitial pneumonia, significantly widened alveolar septum, partial alveolar wall rupture, especially in the high dose group. The pathological scores of lung tissue were all significantly higher in three experiment groups than those in control group (P＜0. 05). The expressions of NLRP3 in lung tissue were higher in low, medium and high dose groups than those of the control group. The expressions of IL-18, IL-1β and Caspase-1 in lung tissue increased in different degrees. Conclusion The lung injury and inflammatory response caused by PM2.5 are related to the activation of NLRP3 inflammasome in alveolar macrophages in rats.