Effect of Dexamethasone on Acute Respiratory Distress Syndrome Induced by H5N1 Virus in Mice

¹ Dept of Pathophysiology, College of Veterinary Medicine, China Agricultural University, Beijing 100094, PR China; and Dept of Veterinary Medicine, College of Animal Science, Hebei North University, Hebei Province, 075000, PR China
² Dept of Pathophysiology, College of Veterinary Medicine, China Agricultural University, Beijing 100094, PR China

^* To whom correspondence should be addressed. E-mail: qiaojian{at}cau.edu.cn.

	Abstract

Glucocorticoids are widely used in treatment of different inflammatory diseases. This study was performed to investigate the effect of dexamethasone (Dex) on acute respiratory distress syndrome (ARDS) induced by H5N1 viral infection in mice.

Six- to eight-wk-old BALB/c mice were divided into 3 groups with 80 mice each. Infected-group and Dex-treated infected-group were inoculated intranasally with 1x10² MID₅₀ of A/Chicken/Hebei/108/2002(H5N1) viruses, with daily intraperitoneal injection of PBS, or 2.5 mg·kg^-1 Dex at days 3 to 14 postinoculation, respectively. Control group received noninfectious allantoic fluid and daily intraperitoneal injection of PBS.

In H5N1-infected mice, Dex treatment could not improve the mortality (17/20 vs. 16/20, Dex-treated infected-group vs. infected-group), and did not alleviate the clinical signs, including weight loss, decreased food intake and inactivity. There was no significant amelioration of the hypoxemia and ARDS-associated pathological changes in Dex-treated infected-mice, as assessed by blood gas analysis and histological score. Furthermore, Dex therapy could not inhibit the inflammatory cellular infiltration and the cytokine release (IL-6 and TNF-) in BALF induced by H5N1 infection.

In conclusion, Dex treatment (2.5 mg·kg^-1) from days 3 to 14 postinoculation has no beneficial effect on ARDS caused by H5N1 infection in mice.