Plenary Poster ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Teriparatide (hPTH1-34) is an anti-osteoporotic drug with bone anabolic effects. Clinical and preclinical studies have indicated that TPTD has value in oral and maxillofacial bone therapies, including jawbone regeneration, periodontal tissue repair, and the treatment of medication-related osteonecrosis of the jaw. However, it is unclear whether the craniofacial bones respond to TPTD similarly to axial and appendicular bones. Recent studies showed that TPTD acts on both osteocytes and osteoblasts. This study aimed to characterize distinct craniofacial bone sites, with a focus on morphometric changes in osteocytic lacunae in ovariectomized rats receiving TPTD. To observe differences in the effects on the craniofacial bones, Rats at 12 weeks of age were subjected to sham surgery or ovariectomy, and each group was injected 30 μg/kg of TPTD or saline three times weekly for 4 weeks (total 4 groups, n=5 per group). Conventional bone histomorphometric analyses of mandibular and parietal bone sections were conducted. High-resolution confocal imaging-based three-dimensional fluorescence morphometric analyses of osteocytic lacunae in distinct mandibular and parietal bone sites were performed. We observed that administration of TPTD to sham-operated rats increased the size of osteocytic lacunae in alveolar bone, whereas the administration of TPTD to OVX rats decreased the size of osteocytic lacunae that had been expanded by OVX. Similar changes in the size of osteocytic lacunae were observed in buccal sites of mandibular bone. These results indicate dynamic changes in the morphometric characteristics of osteocytic lacunae in alveolar bone and other mandibular bone sites upon administration of TPTD. These findings suggest that osteocytes in mandibular bone (specifically, alveolar bone) have unique functional characteristics involving the dynamic regulation of osteocytic perilacunar remodeling, characteristics that are less obvious in other bones.