Abstract:

BACKGROUND: Insulin-like growth factor -Ⅰ (IGF- Ⅰ) is synthesized by osteoblasts and has promotive effects on osteoblast proliferation and differentiation.
OBJECTIVE: To study the effect of central nerves system injury on expression of IGF- Ⅰ in blood serum, bony callus and fracture healing.
METHODS: Wistar rats were randomly divided into 4 groups: normal control group; simple fracture group; brain injury-fracture group; and spinal cord injury-fracture group. The level of IGF- Ⅰ in serum was measured at 1, 2 and 3 weeks after operation. Bony callus healing was evaluated by X-ray films at 2 and 3 weeks after operation. The femur was harvested at 1, 2, 3 and 4 weeks to measure the bony callus volume. The local expression of IGF- Ⅰin fracture sites were determined by immunohistochemical staining at 3 days, 1 and 2 weeks after operation.
RESULTS AND CONCLUSION: The serum IGF- Ⅰ in the normal group and simple fracture group was not changed greatly, but the bone callus volume and X-ray film grades of the brain injury-fracture group and spinal cord injury-fracture group were larger than those in the simple fracture group (P < 0.05). The concentrations of IGF- Ⅰ in the brain injury-fracture group and spinal cord injury-fracture group were increased significantly than those of other two groups at 3 days, 1 and 2 weeks after operation (P < 0.01); the count of positive cells in the brain injury-fracture group and spinal cord injury-fracture group were increased significantly than those of other two groups at 1 week after operation (P < 0.01). The central nervous injuries can increase the concentration of IGF- Ⅰ in blood serum and expression of bony callus, therefore, accelerates fracture healing in rats.