FTY720对百草枯中毒小鼠肺损伤的保护作用

Protective Effects of FTY720 in Murine Paraquat-induced Lung Injury

目的:探讨新型免疫抑制剂FTY720对急性百草枯(PQ)中毒小鼠肺损伤的保护机制。方法:8周龄C57BL/6j小鼠随机分为百草枯40mg/kg染毒对照组(PQ组)、百草枯40mg/kg染毒+FTY720 0.5mg/kg/d干预组(PQ+FTY720组)、生理盐水对照组(Control组)。PQ组和PQ+FTY720组分别经腹腔注射PQ40mg/kg,PQ+FTY720组于2小时后腹腔注射FTY720 0.5mg/kg,每日一次,连续14天;Control组腹腔注射等量生理盐水。各组分别于第3、第28天处死,观察28天生存率,留取支气管肺泡灌洗液(BALF)及肺组织。HE染色观察各组肺组织病理变化。BCA法测定BALF中总蛋白含量。ELISA法检测BALF中IL-6水平。Real-time PCR法测定肺组织中alpha-smooth muscle actin(α-SMA)、type I col1agen、type Ⅲcollagen mRNA的表达水平,免疫组化法观察肺组织中α-SMA的表达。结果:28天生存率PQ组与PQ+FTY720组分别为50%和70%。 HE染色显示FTY720干预后小鼠肺损伤程度较PQ组减轻。PQ+FTY720组在急性期BALF总蛋白含量、IL-6水平明显低于PQ组,慢性期肺组织中α-SMA、type I col1agen、type Ⅲcollagen在mRNA水平上表达较PQ组下调,且均具统计学意义。肺组织α-SMA阳性表达颗粒较PQ组减少。结论: FTY720可抑制部分肺损伤/纤维化相关因子的表达,对百草枯中毒肺损伤有治疗保护作用。

Objective：Acute lung injury induced by paraquat is a devastating disease which is characterized by diffuse alveolitis and extensive lung fibrosis.The aim of this study was to evaluate a new immune modulator—FTY720 on paraquat-induced lung injury in mice.Methods：C57BL/6 mice（8 week old,n=60） were randomly divided into 3 groups.Control group（n=20）：mice were administrated with saline.PQ group（n=20）：mice were administrated with paraquat（40mg/kg）.PQ＋FTY720 group（n=20）：mice were administrated with paraquat（40mg/kg）.2 hours later,FTY720（0.5mg/kg） was give once a day for 14 consecutive days.The administrations of saline,PQ,and FTY720 were all made intraperitoneally.At day 3,mice（n=5） from each group were sacrificed for measurement of total protein and interleukin-6 level in bronchoalveolar lavage fluid（BALF）.The left mice（n=15 for each group） were observed for 28 days to determine survival rates,mRNA level of alpha-smooth muscle actin（α-SMA）,type I col1agen,type Ⅲ collagen and immunohistochemical staining of α-SMA.Hematoxylin and eosin（HE） staining（middle panel） of lung sections was performed in all sacrificed mice.Results：FTY720 treatment caused a significant reduction of total protein and interleukin-6 level in bronchoalveolar lavage at day 3.In addition,at day 28,mRNA levels of α-SMA,typeⅠcollagen,type Ⅲcollagen and immunohistochemical expression of α-SMA in the lung tissues were significantly decreased.These effects were associated with an attenuated histopathological lung lesions induced by paraquat and an improved survival rate at day 28.Conclusion：Our results suggest that FTY720 attenuates lung injury in a mouse model of paraquat poisoning,but further investigation is absolutely necessary.