Changes of osteocalcin and IGF-I during bone lengthening.

Abstract

OBJECTIVE: To examine the changes of osteocalcin and insulin-like growth factor I (IGF-I) during bone lengthening, and to clarify the mechanism of bone healing. METHODS: Thirty-two shepherd dogs were divided into five groups randomly. Their tibiae were lengthened by Ilvzarov's external fixator at the rate of 1 mm/day. The lengthening area was the experimental side and the opposite side was the control. Samples were obtained on the 2nd, 4th, 6th, 8th, 12th weekend respectively. The samples were defatted, dried, powdered, centrifuged and measured by radioimmunoassay. RESULTS: The osteocalcin concentration increased at the subsequent periods, but it was significantly lower in the experimental side than that of the control side, P<0.05 and the IGF-I concentration was not significantly lowered. CONCLUSIONS: Different noncollagenous bone growth factors may be different at different stage.