芥子气经腹腔和气管致大鼠急性肺损伤纤维化指标变化

Changes of pulmonary fibrosis indexes due to sulfur mustard-induced acute lung injury in rats via intraperitoneal and tracheal injection

目的经腹腔和气管复制大鼠芥子气(SM)急性肺损伤动物模型,比较2种大鼠急性肺损伤模型肺纤维化指标的差异。方法选取Sprague Dawley大鼠136只,随机分为5组。腹腔SM组腹腔内注入稀释的SM 0.1 ml(0.96 LD50=8 mg/kg),气管SM组气管内注入稀释的SM 0.1 ml(0.98 LD50=2 mg/kg),腹腔和气管丙二醇组分别腹腔和气管内注入丙二醇0.1 ml,正常对照组不做任何处理。采用Masson染色和免疫组织化学,判断肺纤维化指标变化。结果 1光镜下见72 h肺泡间隔被染成绿色的胶原纤维增多;2腹腔SM组大鼠肺泡间隔各时间段基质金属蛋白酶MMP-2、MMP-9、基质金属蛋白酶组织抑制剂TIMP-1、TIMP-2蛋白阳性表达率分别与气管SM组比较升高(P<0.05);3腹腔SM组大鼠肺泡间隔各时间段肺泡间隔Ⅰ型胶原、Ⅲ型胶原蛋白阳性表达率分别与气管SM组比较升高(P<0.05);4腹腔SM组大鼠肺泡间隔各时间段肺泡间隔转化生长因子(TGF-β1)、母亲DPP同源物7(Smad7)蛋白阳性表达率分别与气管SM组比较升高(P<0.05)。结论大鼠在经腹腔和气管SM LD50浓度相似的情况下,经腹腔途径肺纤维化指标与经气管比较升高,提示SM经腹腔途径更容易诱导肺纤维化。

Objective To establish rat model of sulfur mustard （SM）-induced acute lung injury via intraperitoneal and tracheal injection, in order to compare the differences of pulmonary fibrosis indexes. Methods A total of 136 male Sprague Dawley rats were randomly divided into the five groups, i.e. the control group with 8 rats and other four groups （intraperitoneal SM group, intraperitoneal propylene glycol group, tracheal SM group and tracheal propylene glycol group） with 32 rats in each group. The rats in the intraperitoneal SM group were intraperitoneally injected with 0.1 ml diluted SM （0.96 LD50 = 8 mg/kg）, the rats in the tracheal SM group were intratracheally injected with 0.1 ml diluted SM （0.98 LD50 = 2 mg/kg）, the rats in the intraperitoneal propylene glycol group and the tracheal propylene glycol group were injected with 0.1 ml propylene glycol through peritoneal cavity and trachea respectively; meanwhile the status quo was kept with the normal control group. SM-induced pulmonary fibrosis indexes were observed by Masson and immunohistoehemical staining. Results Light microscopic observation confirmed that green-stained collagen fibers increased in the alveolar septa at 72nd h. Significantly higher positive expression rates of MMP-2, MMP-9, TIMP-1 and TIMP-2 by immunohistochemical staining in the alveolar septa were detected in the intraperitoneal SM groups compared with those in the tracheal SM groups at each period of time （P 〈 0.05）. The positive expression rates of type I collagen and type Ⅲ collagen in the alveolar septa in the intraperitoneal SM groups were significantly increased compared with those in the tracheal SM group at each period of time （P 〈 0.05）. Significantly higher positive expression rates of TGF-β1 and Smad7 in the alveolar septa were also observed in the intraperitoneal SM group compared with the tracheal SM group at each period of time （P 〈 0.05）. Conclusions When LD50 concentration of SM through intraperitoneal injection is similar to that through tracheal injection in rat, the indexes of pulmonary fibrosis are significantly increased after intraperitoneal injection compared with those after tracheal injection, suggesting that SM-induced pulmonary fibrosis can be more easily induced through intraperitoneal injection.