Treatment study of distal femur for parathyroid hormone (1-34) and ß-tricalcium phosphate on bone formation in critical-sized defects in osteopenic rats.

ABSTRACT

The objective of this study was to evaluate the effect of following combined treatment with parathyroid hormone (1-34) (PTH) and ß-tricalcium phosphate (ß-TCP) on local bone formation in a rat 3-mm critical-sized defect at the distal femur. Fourteen weeks were allowed to pass before defect surgery for the establishment of osteopenic animal models chronically fed a low-protein diet. All animals were randomly divided into four groups group PTH; group ß-TCP, group PTH + ß-TCP, and a control group. All rats then underwent a surgical procedure to create bone defects in the bilateral distal femurs, and ß-TCP was implanted into critical-sized defects for the groups designated as ß-TCP and group PTH + ß-TCP. After the defect operation, all animals from group PTH and group PTH + ß-TCP received following subcutaneous injections with PTH (60 µg/kg, three times per week) until euthanasia at 4 and 8 weeks. The distal femurs and blood were collected for evaluation. The results of study showed the strongest effect on accelerating the local bone formation with treatment ß-TCP and PTH at 4 weeks and 8 weeks. The results from our study demonstrate that a combination of PTH and ß-TCP had an additive effect on local bone formation in osteopenic rats chronically fed a low-protein diet.