Long-term toxicity to respiratory system of rats by low-dose perfluoroisobutylene exposure once and possible beneficial effect of early intervention via Qingkailing injection / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To clarify the long-term toxicity to the respiratory system in a rat model of acute lung injury (ALI) induced by a single low-dose of perfluoroisobutylene(PFIB) inhalation expo?sure,and observe the possible beneficial effect of early intervention via Qingkailing(QKL) injection. METHODS Totally 224 male Wistar rats were randomly divided into 4 groupsnormal control group in which air exposure was followed by a saline 10 mL · kg-1(ip),QKL control group in which QKL 10 mL · kg-1 was ip given after air exposure,PFIB exposure group in which rats were exposed to PFIB 280 mg·m-3 for 5 min only,and QKL treatment group in which QKL 10 mL·kg-1 was given ip at 1 h after PFIB exposure. Lung functions of rats were measured at 24 h,3,6,12,24,36 and 48 weeks after exposure. The arterial blood gas,lung coefficient,protein content in bronchoalveolar lavage fluid(BALF),hydroxy?proline(HYP) content in lung tissue and plasma,and other indicators were detected or analyzed. RESULTS Within 24 h after PFIB exposure,the lung coefficient and protein content in BALF were increased significantly(P<0.01),whereas the PaO2(P<0.01) and SaO2(P<0.05) indices in arterial blood decreased significantly in PFIB group compared with normal control. The inhalation time , exhalation time,tidal volume(TV),expired volume(EV)and relaxed time were reduced significantly (P<0.01). However,all the above indicators returned to normal in 3 weeks,but TV,EV and peak expiratory flow were significantly lower than in normal group at 48 weeks(P<0.05). HYP contents in lung tissues,compared with normal control(P<0.05),were reduced significantly within 24 h after PFIB exposure,increased significantly in 6 weeks(P<0.05),then returned to normal in 12 weeks. HYP contents in plasma increased significantly compared with normal control(P<0.05) within 24 h after PFIB exposure but returned to normal in 3 weeks. The protein contents in BALF of QKL treatment group were significantly lower than those in PFIB group(P<0.01) within 24 h after PFIB exposure. From 24 h to 24 weeks after PFIB exposure,changes of pulmonary functions were similar to those in PFIB group. At 48 weeks,TV and EV in QKL treatment group were more significantly increased than those in PFIB group(P<0.05). CONCLUSION Rats with ALI induced by a single low dose of PFIB exposure undergo compensatory repair except for pulmonary capacity and pulmonary ventilation functions. Early treatment with QKL reduces protein content of BALF and alleviates pulmonary edema,and has some beneficial effect on lung function recovery later.