Protective Effect and Mechanism of Alprostadil in Acute Respiratory Distress Syndrome Induced by Oleic Acid in Rats

Yan, Xiujuan; Li, Yingxiu; Choi, Yun Ho; Wang, Chongyang; Piao, Yihua; Ye, Jing; Jiang, Jingzhi; Li, Liangchang; Xu, Huixian; Cui, Qingsong; Yan, Guanghai; Jin, Minggen

Fibrosis was evaluated using Masson's trichrome-stained sections. The sections were observed under 200× magnification with a microscope (VANOX, Olympus, Japan). A blue signal indicated positive staining for collagen. The extent of fibrosis in these sections was graded using the following criteria: none (0), no evidence of fibrosis; mild (1+), focal regions of fibrosis involving less than 20% of the lung. Fibrosis involved the pleura and the interstitium of the sub-pleural parenchyma with some distortion of alveolar architecture; moderate (2+), more extensive fibrosis involving 20%-50% of the lung and fibrotic regions mostly extending inward from the pleura and still focal; and severe (3+), widespread fibrosis, involving more than 50% of the lung. Confluent lesions with extensive derangement of parenchymal architecture included cystic air spaces lined by cuboidal epithelium [34] .