Effect of Systemic rhPTH on Critical-Size Rat Calvarial Defect

JAMMAL M V, PASTORINO N F,M, MISSANA L R.

Foz de Iguazu

Congreso; IADR General Session; 2012

IADR

Objective: Intermittent Recombinant Human Parathyroid Hormone (rhPTH 1-34) is an effective treatment for improving bone mass in patients with osteoporosis; however, its effects on CZD bone regeneration are still unclear. The objective of this study was to evaluate the ability of systemic rhPTH to regenerate bone critical-sized defects (CZD), as well as its potential toxicity. Method: We used 43 female Wistar rats (body weight, 150 ± 50 g). Critical-sized bone defects in rat calvaria received vehicle alone (CG) or daily rhPTH (20 μg/Kg/day) by subcutaneous injection (Experimental Group, EG). We evaluated bone healing obtained at the 1st, 3rd, and 6th wks post-surgery by biochemical, soft x-ray, histological, and morphometric studies. Result: In the EG, at the 1st and 3rd wks, many areas of focal osteoblast hyperplasia were found on parietal bone. At the 3rd wk, woven and/or lamellar bone, in an organized interconnected trabecular network, showed disrupted mineralization. At the 6th wk, looped bone was found to have formed patterns on parietal bone. New bone formed in the EG showed significant statistical differences (p = 0.023) at the 6th wk. Conclusion: The systemic rhPTH 20 μg/Kg/day dose was unable to regenerate rat CZD; however, it induced both typical and atypical proliferative bone hyperostosis.