Effects of dexamethasone pretreatment on expression of angiopoietin-1, 2 in rats with acute lung injury induced by phosgene

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 groups: normal 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. Key words: Dexamethasone; Phosgene; Acute Lung Injury; Angiopoietin-1 (Ang-1); Angiopoietin-2 (Ang-2)