Objective: This study was conducted to disclose the rules of collagen type I and II production and hence to acquire knowledge about the mechanism of repairing during the second period of fracture healing.
Methods: An experimental model of second fracture healing at rat's femurs was used to study the production of collagen type I and II by means of immunohistochemistry; meanwhile the histologic changes were observed with the use of HE staining and Alcian blue staining at 3 days, 1, 2, 3, 4 weeks postoperatively.
Results: The expression of both collagen type I and II was detected by immunohistochemistry at 1 week. The peak expression of collagen type II occurred at 3 weeks. The higher expression of collagen type I was observed at 4 weeks.
Conclusion: The morphologic changes of chondrocyte and the production of collagen type I and II by chondrocyte in cartilage callus are correlated with their repairing function during different periods of fracture healing.