The number of apoptosis cells in DXM was more than that in BLM,and the collagenic fiber in DXM was less than that in BLM under transmissional electron microscope.

• ( 5 )形态学观察 :DXM各时间组与BLM组比较 :凋亡细胞明显增多 ; BLM 2 8d组肺泡间质胶原明显多于DXM组 ,纤维母细胞增多 ;