不同剂量鞭毛蛋白致大鼠急性肺损伤的对比研究

Contrast investigation of rat acute lung injury induced by different doses of flagellin

目的研究经大鼠尾静脉注入不同剂量鞭毛蛋白后,观察不同时相点急性肺损伤(acute lung injury,ALI)发生的情况,探讨其发生的可能机制。方法240只清洁级雄性Wistar大鼠分为4组:对照组、致伤1组、致伤2组和致伤3组。对照组给予生理盐水,各致伤组分别给予5、50、500μg/kg的鞭毛蛋白,于静注后2、4、6、12、24、48h,测定动脉血氧分压(PaO2)、肺组织湿干比值(W/D)、血清与支气管肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)和白介素-lβ(IL-lβ)细胞因子的含量以及观察肺组织的病理改变。结果静注鞭毛蛋白后,在对应时相点,鞭毛蛋白注入剂量越大,大鼠PaO2越低,肺W/D越高;外周血及BALF中,细胞因子TNF-α、IL-lβ含量越高;肺组织病理改变越明显。以上各指标在各对应时相点,致伤2、3组与对照组比较差异有统计学意义(P<0.01);致伤2、3组与致伤1组间也有显著性差异(P<0.01);致伤2组与致伤3组间仅TNF-α含量比较差异有统计学意义(P<0.01)。结论鞭毛蛋白可致大鼠急性肺损伤,且其具有剂量和时间的差异性。

Objective To investigate the development of acute lung injury （ALI） of rats at different time phases after injection of different doses of flagellin via caudal vein and to approach the possible mechanism. Methods Totally 240 clean female rats were randomized into 4 groups, i. e. , the normal control group and the 1st, 2nd and 3rd injury groups. Normal saline was given to the control group, and flagellin was given to 3 injury groups, with dose of 5, 50 and 500 μg/kg respectively. Arterial partial pressure of oxygen （ PaO2 ）, and ratio of wet and dry lung tissue （W/D） were determined at 2, 4, 6, 12, 24 and 48 h after injection. The histological changes of lung tissue were observed and concentrations of tumor necrosis faetor-α（ TNF-α）, interleukin- 1β（IL-1β） in peripheral blood and bronchoalveolar lavage fluid （BALF） were determined at the above-mentioned time points by ELISA. Results After injection of flagellin, at the same time points, larger dose of flagllin led to a lower PaO2, higher W/D of lung tissue, and higher concentrations of TNF-α and IL-1β in peripheral blood and BALF, and the histological changes of lung were more remarkable. Among all above indexes, there was significant differences between control group and injury groups at every time points （P 〈 0.01 ）, of the 2nd and 3rd injury groups with the control group （ P 〈 0.01 ） , more significant differences of the 2nd and 3rd injury groups with the 1st injury group （P 〈0.01 ）. The only significant difference between the 2nd injury group and the 3rd injury group was in TNF-α concentration （P 〈0.01 ）. Oonclusion Intravenous injection of flagellin may lead to acute lung injury in rats in a dose- and time-dependent manner.