Influence of cyclooxygenase-2 inhibitor on the expressions of surfactant protein B and transforming growth factor β1 of newborn rats in hyperoxia environment / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the effects of selective cyclooxygease-2 inhibitor on pulmonary surfactant protein(SP-B) and transforming growth factor(TGF-β1) of hyperoxic lung injury in newborn rats.Methods One hundred and five SD rats were randomly divided into 3 groups (35 cases in each group)air group (group Ⅰ),in which the rats were exposed to room air;hyperoxia group(group Ⅱ),in which the rats were exposed to hyperoxia(850 mL/L oxy gen);Celecoxib group(group Ⅲ),in which the rats were exposed to heyperoxia(850 mL/L oxygen) and intraperitoneally injected with 5 mg/kg Celecoxib.The lungs of rats were removed on 3 d,7 d,14 d after birth and the following indices were measuredlung section from the lower right lung were stained with HE,and the histological changes was examined;the contents of SP-B and TGF-β1 in the bronchoalveolar lavage fluid of left lung was determinated by using enzyme-linked immunosorbent assay (ELISA);right upper lung was immunohistochemically stained to measure the contents of SP-B and TGF-β1,quantitative real-time PCR(RT-PCR) was used to detect the mRNA expression of SP-B and TGF-β1.Results There were no inflammatory cells and exudation in the lung in group Ⅰ;in group Ⅱ,the structure disorder,pulmonary edema,and inflammatory infiltrates were found;but the damage was obviously alleviated in group Ⅲ.Protein expression could be better detected by ELISA,at the time of 14 day,SP-B was expressed at different levels in3 groups(29.93±6.40) ng/L in group Ⅰ,(18.20 ±3.70) ng/L in group Ⅱ and (19.63 ±10.20) ng/L in group Ⅲ,SP-B level in group Ⅱ was significantly lower than that in group Ⅰ (t =13.152,P ＜ 0.01),and the expres sion in group Ⅲ was significantly higher than that in group Ⅱ (t =5.190,P ＜ 0.01).TGF-β1 was expressed at different levels in 3 groups(34.73 ±2.30) μg/L in group Ⅰ,(41.66 ± 1.80) μg/L in group Ⅱ and (38.03 ±0.20) μg/L in group Ⅲ,and the level of TGF-β1 was significantly higher in group Ⅱ than that in group Ⅰ (t =6.584,P ＜ 0.01),but the expression of group Ⅲ was significantly lower than that in group Ⅱ (t =5.609,P ＜ 0.01).The expression of mRNA was detected by RT-PCR,and at the time of 14 day,SP-B mRNA was expressed at different levels in 3 groups3.14 ±0.10 in group Ⅰ,0.81 ±0.06 in group Ⅱ and 1.12 ±0.06 in group Ⅲ,and SP-B level in group Ⅱ was significantly lower than that in the group Ⅰ (t =55.050,P ＜0.01),and the expression in group Ⅲ was significantly higher than that in group Ⅱ (t =10.305,P ＜ 0.01).TGF-β1 mRNA was expressed at different levels in the 3 groups1.94 ±0.03 in group Ⅰ,13.26 ±0.43 in group Ⅱ and 6.49 ±0.26 in group Ⅲ,the level of TGF-β1 was significantly higher in group Ⅱ than that in group Ⅰ (t =75.471,P ＜ 0.01),while the expression of group Ⅲ was significantly lower than that in group Ⅱ (t =38.470,P ＜ 0.01).Conclusions Cyclooxygenase-2 inhibitor can attenuate hyperoxic lung injury in rats,and the mechanism might be related to the reduction of prostaglandin.