Abstract: Objective: To observe the influence of acute pulmonary injury induced by adriamycin(ADM) on β-defensin-2(BD-2) gene expression in rats.Methods: Forty male Sprague-Dawley rats were randomly divided into four groups:low dose ADM group,medium dose group,high dose group and control group.The ADM groups were administered ADM of different doses(10,20 and 40 mg·kg^-1·d^-1).Meanwhile,normal saline was given to the control group.All the rats were killed three days later,and the lung tissues were removed by thoracotomy.The expression of BD-2 at mRNA level was determined by RT-PCR analysis.Results: The level of BD-2 gene expression in medium-dose and high-dose groups was up-regulated significantly compared with that in the control group(P<0.01);and the difference had no statistical significance between the low-dose group and the control(P>0.05).Conclusions: The level of BD-2 gene is up-regulated in the lung tissues of rats with acute pulmonary injury induced by ADM.