Molecular Aspect of Osteoporotic Fracture Healing
Protein expression of growth factors involved in fracture healing and osteoporosis were investigated in ovariectomised (OVX) rat fracture model using histological and immunohistochemical analysis. The OVX model was confirmed by a significantly increased body weight and reduced bone density of the non-fracture hind limbs. The tissue morphology and the protein expression were assessed on the paraffin sections of the fracture callus at day 7, 14, 28 and 42 after fracture. Histology revealed a significantly higher ratio of fibrous tissue over bone or cartilage over bone in the fracture callus at day 28 and 42 in the OVX rats than in the normal rats. Immunohistochemical staining of IGF-I, IGF-IRα, MMP-1, TIMP-1 and 2 showed a different pattern between the OVX and the control groups. A down-regulation of IGF-I and TIMP-1 and an up-regulation of MMP-1 were observed in OVX rats, which may account in part for the delayed healing of the osteoporotic fracture and may affect extracellular matrix composition, an important determinant of callus strength.
Yu Zhou, Shan-Tung Tu and Xishan Xie
A. K. Low et al., "Molecular Aspect of Osteoporotic Fracture Healing", Key Engineering Materials, Vols. 353-358, pp. 2159-2162, 2007