Effects of teriparatide on bone formation in rats with experimentally induced premaxillary expansion

ABSTRACT Objective: This study aimed to evaluate the effects of systemic teriparatide on sutural bone formation after premaxillary suture expansion in rats. Material and Methods: Twenty Wistar male rats (8-10 weeks old) were randomly divided into two groups, namely, control (C, n=10) and teriparatide (T, n=10). An expansion force was applied to the maxillary incisors using helical spring for a seven-day expansion period, for both groups. On the eighth day, the rats were kept for a seven-day consolidation period, and then 60 µg/kg teriparatide (once a day) was administered to group T subcutaneously for seven days. Then, all the rats were sacrificed, and histological sections were stained with hemotoxylin-eosin for examination. Anti-osteonectin, anti-osteocalcin, anti-Vascular endothelial growth factor (VEGF) and anti-transforming growth factor beta (TGF-β) were evaluated by immunohistochemical analysis in the midpalatal suture area. Results: Histologically, the newly formed bone tissue was observed to be larger in group T than in group C. The number of immunoreactive osteoblasts for osteonectin, osteocalcin and VEGF antibodies was significantly higher in group T than in group C (p = 0.0001). The TGF-β antibody showed a mild reaction in group T, but did not reach significance in comparison with group C (p ˃ 0.05). Conclusion: Systemic teriparatide application following the premaxillary expansion of the suture area may stimulate bone formation and add to the consolidation of the expansion in rats by regulating osteonectin, osteocalcin and VEGF. RESUMO Objetivo: O presente estudo teve como objetivo avaliar os efeitos do uso sistêmico da teriparatida na formação óssea sutural após a expansão da pré-maxila em ratos. Material e Métodos: Vinte ratos machos da raça Wistar (com oito a dez semanas de vida) foram divididos aleatoriamente em dois grupos: controle (C, n=10) e teriparatida (T, n=10). Uma força de expansão foi aplicada aos incisivos superiores, usando uma mola helicoidal, por um período de expansão de sete dias em ambos os grupos. No oitavo dia, os ratos iniciaram um período de sete dias de consolidação, nos quais 60 µg/kg de teriparatida foram administrados (uma vez ao dia), por via subcutânea, para o grupo T. Posteriormente, todos os ratos foram sacrificados e cortes histológicos corados com hemotolixina-eosina foram examinados. Por meio de análise imuno-histoquímica da região da sutura palatina mediana, avaliou-se a presença de anti-ostenectina, anti-o