[An experimental study on the repair mechanism after pulmonary embolism]

To study the role of basic fibroblast growth factor (bFGF) and small vascular density in the repair mechanism after pulmonary embolism (PE).

After peripheral pulmonary arteries had been embolized, 8 dogs were killed 1, 7, 14, and 28 days after embolization. One piece of tissue was taken from the region embolized and unembolized respectively, then HE staining and immunohistochemical staining were performed. The pathological change of the lung, changes of small vascular density and expression of bFGF were observed, and were compared between regions embolized and unembolized at different time points.

(1) The course of pathological change during the pulmonary embolism period. (2) The bFGF was increased from 1st day to 14th day after PE (1st day: chi(2) = 44.335, 7th day: chi(2) = 71.911, 14th day: chi(2) = 84.460; P < 0.01), and decreased to normal on 28th day (chi(2) = 2.961, P > 0.05). (3) Small vascular density in embolized region (4.56 +/- 0.50) showed no statistical difference from that of unembolized region (4.11 +/- 0.76) on 1st day (P > 0.05), while it (7th day: 10.17 +/- 1.08, 14th day: 10.54 +/- 0.93, 28th day: 11.47 +/- 1.11) was significantly higher than that of unembolized region (7th day: 6.17 +/- 0.90, 14th day: 7.55 +/- 1.19, 28th day: 7.03 +/- 1.24) after embolized 7, 14, 28 days (P < 0.05).

After PE, with increased expression of bFGF in embolized region, the formation of collateral arteries between pulmonary artery system and bronchial artery system is promoted, and absorption of the transuded blood cells and fluid is accelerated. This mechanism may be important in prevent pulmonary infarction.