大鼠肺纤维化模型中NLRP3、IL-18表达及意义的探讨

Expression and significance of NLRP3 and IL-18 axis in pulmonary fibrosis rat model

目的观察博来霉素致肺纤维化大鼠肺组织中NLRP3、IL-18的表达水平,探讨其在肺纤维化发生、发展中的意义。方法将45只清洁级Wistar大鼠按随机数字表法分为健康对照组(N组)、博来霉素组(B组)、地塞米松治疗组(D组),每组大鼠各15只,B组及D组大鼠给予气管内注射博来霉素4mg/kg制作肺纤维化模型,N组给予相同体积生理盐水作为对照,D组大鼠于肺纤维化造模基础上第2天每日腹腔注射地塞米松3mg/kg,N、B组大鼠腹腔注射生理盐水作为对照。各组大鼠分别于造模后7、14、28天处死,HE染色评价肺组织病理形态学变化,碱水解法及酶联免疫吸附法分别测定肺组织匀浆中羟脯氨酸(HYP)、NLRP3含量,RT-PCR法测定肺组织中IL-18mRNA表达量。结果 (1)HE染色示B、D组大鼠第7天肺间质和肺泡腔内可见大量炎细胞浸润,此后炎症随时间推移逐渐减轻,逐渐发展为晚期纤维化性变;B、D组HYP含量随时间推移逐渐升高,以28天为著,P<0.05;(2)B、D组NLRP3、IL-18mRNA表达于第7天升高至最高点,后逐渐降低,至28天均高于N组,差异有统计学意义(P<0.05);(3)D组NLRP3、IL-18mRNA表达在同一时间均低于B组,P<0.05。结论 NLRP3、IL-18在大鼠肺纤维化发病早期起重要作用,可能参与了肺纤维化发生与发展。

Objective To study the expression of NLRP3 and IL-18 in pulmonary tissue of bleomycin-induced pulmonary fibrosis rats,and to explore the expression and significance of NLRP3 and IL-18 in PF.Methods 45 clean Wistar rats were randomly divided into the healthy control group(the N group),the bleomycin group(the group B),and the dexamethasone treatment group(the group D),15 rats in each group.The group B and D were given intratracheal injection of bleomycin 4mg/kg pulmonary fibrosis model,and the group N was given the same volume of saline as control.On the basis of pulmonary fibrosis model,the group D was daily given intraperitoneal injection of dexamethasone 3mg/kg from the second day,and the group B and N was treated with intraperitoneal injection of saline as controls.The rats in each group were sacrificed at 7,14 and 28 days after modeling.The histopathological changes of lung tissue were evaluated by HE staining.Hydroxyproline(HYP)in lung tissue homogenate was determined by alkaline hydrolysis and enzyme,and NLRP3 content and RT-PCR were used to detect the expression of IL-18 mRNA in lung tissue.Results (1)HE staining showed that the pathological changes of lung tissue in the group B and D were observed.On the 7th day,a large number of inflammatory cells were found in the interstitial and alveolar lumen,and the inflammation gradually decreased with the passage of time,and gradually developed into late fibrosis(P<0.05).(2)The expression of NLRP3 and IL-18mRNA in the group B and D increased gradually to the highest point on Day 7,and then decreased gradually(P<0.05).(3)The expression of NLRP3 and IL-18mRNA in the group D was lower than that in the group B at the same time(P<0.05).Conclusion NLRP3 and IL-18 play important roles in the early stage of pulmonary fibrosis and may be involved in the development and progression of pulmonary fibrosis.