Abstract
1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] has been used in the treatment of myelofibrosis and beneficial effects have been observed. The mechanism of this effect still remains unclear. The present study examined whether 1,25(OH)2D3 directly affects bone marrow fibroblast proliferation and collagen synthesis. Third to sixth subcultures of rabbit bone marrow fibroblasts were used. 1,25(OH)2D3 exerts dose-related response-inhibitory effects on collagen synsthesis. 1,25(OH)2D3 significantly inhibited collagen synthesis at 10–9 to 10–7M, while 25(OH)D3 was not different from controls. Furthermore, 1,25(OH)2D3 exerted its effect on collagen synthesis without affecting cellular proliferation. Both the cellular protein content and tritium-labeled thymidine incorporation after treatment with either 1,25(OH)2D3 or 25(OH)2D3 were not different from controls.