Abstract: Objective To investigate the effect of recombinant human lactoferrin (rhLF) on fracture healing in rat models with femur fracture and the proliferation of rat primary osteoblasts. Methods Male rats were randomly divided into 3 groups: simple fracture group (SF group), collagen film-treated group (CF group) and rhLF-compound collagen lamination film-treated group (CLF group). The fracture healing was observed by X-ray image and histological microscopy with HE and Masson staining. The newborn SD rats with osteoblasts were treated with different concentrations of rhLF, and osteoblast proliferation was detected by MTT method. Results The bone scabs in the CLF group were significantly larger than those in the SF and CF groups at 1, 2, and 3 weeks postoperatively (P＜0.05). There was no difference in the comparison between the groups at 4th week. The proliferation of cartilaginous and sclerotic bone scabs in the CLF group was more pronounced and showed the appearance of mature trabeculae and lamellar bone with a high degree of maturation of the bone scabs. The groups with 100 mg/L and 500 mg/L rhLF showed a significant decrease in A value for rat primary osteoblasts cultured in vitro as compared with the control group(P＜0.05). The A value increased significantly at the first day (P＜0.05). The concentration of rhLF increased at the fifth and tenth days. Conclusions rhLF has an accelerating effect on fracture healing which is manifested by fast scab formation, large volume and high maturity. The rhLF can promote the proliferation of osteoblasts cultured in vitro, and the effect is mainly manifested in the rapid proliferation stage of osteoblasts.

Key words: recombinant human lactoferrin, fracture healing, osteoblast, femur fracture, rat