The Role of the Transforming Growth Factor-?1 and the Vascular Endothelial Growth Factor in the Angiogenesis of the Bleomycin Induced Pulmonary Injury / 实用放射学杂志

ABSTRACT

Objective To explore the role of the transforming growth factor-?1 (TGF-?1) and the vascular endothelial growth factor (VEGF) in the occurrence and development of the pulmonary fibrosis as well as the synthesis and distribution of these two factors in relation to the angiogenesis process of the pulmonary tissues. Methods The rats were randomly assigned to control group (CG) and bleomycin group (BLM) with the same physical conditions. The bleomycin was introduced to the lung tissues of the rats in the BLM group to mimic the pulmonary fibrosis process. The synthesis and distribution of VEGF and TGF-?1 were observed and recorded on day 3, 7, 14, and 28 in both groups by the immunohistochemical and in situ hybridization approaches. The pathological changes of the subjects were also observed and recorded using both the light-microscope and the transmission electron microscope (TEM) on the same dates.Results The BLM group demonstrated the great significance in both of the VEGF and TGF-?1 presentation and the pathological changes in the pulmonary tissues comparing to the CG group. In the BLM group, VEGF and TGF-?1presented dramatically in the early stages of the fibrosis and this phenomenon lasted with the parallel increases of both the factors. This presentation of VEGF and TGF-?1 showed the greatest distribution on day 28 in the lung interstitial cells and the areas of the presentation corresponded to that of the new angiogenesis and the fibrohyperplacia of the pulmonary tissues. The endothelial cells of the lung capillaries were observed to demonstrate early necrosis, separation from the base, and increased penetrance followed by a great amount of angiogenesis with twisted new blood capillaries and blood embolism formation within, which continued to show on day 28 in the BLM group.Conclusion The presentation of VEGF and TGF-?1 is highly corresponded with the angiogenesis of the bleomycin treated pulmonary tissues in the rats. The continued significant presentation of these two factors may relate to the damage of the new formed capillaries or the impairment of the pulmonary tissues in rats.