FTY720对百草枯中毒小鼠肺损伤的保护作用

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。

Protective Effects of FTY720 in Murine Paraquat-induced Lung Injury

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(H&E) 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.