Effects of dexamethasone pretreatment on expression of angiopoietin-1, 2 in rats with acute lung injury induced by phosgene / 中华急诊医学杂志

ABSTRACT

Objective To investigate the effect of dexamethasone on expressions of angiopoietin-1,2 (Ang-1,2) in rats with acute lung injury induced by phosgene.Methods A total of 36 SD rats were randomly (random number) divided into 3 groupsnormal control group that consisted of the rats with air exposure,phosgene group that consisted of the rats with exposure to 8.33 mg/L phosgene (purity 100％,of the same volume as the inhaled air in the normal control group) for 5 minutes and dexamethasone group that consisted of the rats with caudal vein injection of 2.5 mg/kg dexamethasone an hour before exposure to the same dose of phosgene.Wet and dry ratio of the lung (W/D) was calculated,and leukocyte count and total protein content of bronchoalveolar lavage fluid (BALF) were recorded 2 hours later.The concentrations of Ang-1,2 in the serum and BALF were measured by enzyme-linked immunosorbent assay (ELISA).Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the mRNA levels of Ang-1,2 and Tie-2 in the lung tissue.The protein expression of Ang-1,2 and Tie-2 in the lung tissue were quantified by Western blot.Results Compared with phosgene group,the lung W/D,protein content of BALF and WBC count in dexamethasone group were significantly decreased (P ＜ 0.01).Compared with normal control group,Ang-1 and Tie-2 expressions in phosgene group were significantly decreased (P ＜ 0.01).Compared with phosgene group,the serum,BALF and lung tissue of Ang-1 and Tie-2 expressions in dexamethasone group was significantly increased (P ＜0.01).Compared with normal control group,the serum,BALF and lung tissue of Ang-2 expressions in phosgene group were significantly increased (P ＜ 0.01).Compared with phosgene group,the serum,BALF and lung tissue of Ang-2 expressions in dexamethasone group were significantly decreased (P ＜ 0.05,P ＜ 0.01).Conclusion Dexamethasone has a beneficial effect on acute lung injury induced by phosgene in rats by inhibition of Ang-2 and increase in Ang-1 and Tie-2 expressions.