Combined treatment with alendronate and Drynaria rhizome extracts : Effect on fracture healing in osteoporotic rats.

The effects of both alendronate (ALN) and Drynaria rhizome extracts (DRE) alone could promote bone healing in osteoporotic fractures but there are no reports about the combined use of ALN and DRE for promotion of bone healing of fractures in osteoporotic settings. This study investigated the effects of ALN plus DRE on fractures in osteopenic rats. Osteopenic rats underwent unilateral transverse osteotomy on the femur fixed by a sterilized Kirschner wire 2 weeks after intragastric administration of retinoic acid (80 mg/kg body weight/day). Subsequently, the animals were randomly divided into four groups: control, ALN, DRE and ALN + DRE. All rats from groups ALN, DRE and ALN + DRE received ALN (40 mg/kg, weekly), DRE (90 mg/kg/day), or both for 2, 4 and 6 weeks. The results of our study indicated that all treatment promoted fracture healing and callus formation compared to controls but ALN + DRE treatment showed significantly stronger effects than ALN or DRE alone in histological, X‑ray and biomechanical tests. These results seem to indicate that combined treatment with ALN and DRE has an additive effect on fracture healing and callus formation in osteoporotic rats.