Abstract
The relationship between morphologic changes in the heart after irradiation and expression of the cytokines, transforming growth factor β3 (TGFβ3), platelet derived growth factor A chain (PDGF-A), and basic fibroblast growth factor (bFGF), was assessed.
Sixty C57B1/6 male mice were irradiated or sham irradiated with a split dose, 2 × 15Gy, three days apart. Hearts were removed from each group three days, two weeks, four weeks, eight weeks, and 12 weeks, after the completion of irradiation, and prepared for histological and immunohistochemical study. Expression of TGFβ3, PDGF-A, and bFGF was evaluated by immunohistochemistry.
In the irradiated group, local degeneration of cardiac myocytes, local fibroblastic change, and the expression of TGFβ3 in the same area were observed in 7.5% of the mice. Slight fibrous thickening of pericardium and the expression of TGFβ3 and bFGF were observed in 25% of the mice in the irradiated group. The myocardium tended to be thinner in the irradiated group than the sham irradiated group.
The results of this study suggested that TGFβ3 and bFGF may contribute to the fibrosis that occurs in the pericardium and myocardium after irradiation of the heart.
