The thickness of wall increased and the cavity became narrow, and the Thickness Index (TI) and Area Index (AI) increased in middle and small pulmonary arteries after 2wks and 4 wks of intratracheal BLM.

• 肺动脉病理：幼兔气管内注射BLM 2周与4周后中小肺动脉管壁增厚、管腔变小，肺动脉管壁的TI及AI明显增加。