mice were separated into two groups at random (n=6 for each group) and exposed to benzene (Aladdin, Shanghai, China) aerosol of 0 (group A) and 50 ppm (group C) in the whole body through dynamic inhalation chambers (Tianjin HOPE industry & trade Co., Ltd, Tianjin, China), respectively. The exposure period was seven weeks, for 6 h/d and 6 d/week.