The expressions of fibroblast growth factor (FGF) and related genes play an important role in bone regeneration and repair process.OBJECTIVE:
To compare the new bone formation and the expression of fibroblastic growth factor (FGF) and related genes following distraction osteogenesis between the young and aged rats, and to study the effect of FGF on new bone formation during tibia distraction osteogenesis.DESIGN, TIME AND SETTING:
The randomized controlled animal experiment was performed at the Center Laboratory of The Third Xiangya Hospital of Central South University between January and March, 2007.MATERIALS:
Twenty healthy male Sprague Dawley rats were divided into young group of 3 months old and old group of 12 months old, 10 rats in each group.METHODS:
Low energy osteotomy was performed to all the rats at the upper-middle part of the left tibia followed by placement of the external fixators. Tibia lengthening was initiated after 2 days, 0.2 mm once, twice per day and continued for 14 days. The animals were sacrificed and the tibial samples were collected at the 15th day.MAIN OUTCOME MEASURES:
Quantitative analysis of the bone mineral density and bone area by X-ray; quantitative analysis of endosteal ossification and periosteal reaction by histology method; analysis of FGF and related gene expression using reverse transcription - polymerase chain reaction.RESULTS:
The new bone formation area and bone mineral density in traction area and percentage of endosteal osteoblasts and periosteal osteoblast were significantly higher in the young rats than in the aged rats (P < 0.05,0.01), while the expressions of FGF and related genes in the aged rats were significantly lower than those in the young rats.CONCLUSION:
Impaired bone formation in the aged rats is most likely associated with decreased expression of local growth factors.