Comparative analysis of alveolar repair in female C57BL/6 mice in ovarian failure caused by senescence, chemically induced or by ovariectomy.

Author(s)

Ana Carolina Zucon Bacelar

• Document type: Master's Dissertation
• Press: Araçatuba. 2022-02-24.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2022-02-15
• Advisor: Mariza Akemi Matsumoto

Abstract

Different animal models are used to investigate postmenopausal metabolism and bone repair, resulting in different impacts on ovarian hormone production. The present work analyzed and compared the intramembranous bone repair process after tooth extraction in female mice in physiological stropause, chemically induced and by ovariectomy, as well as the serum levels of bone markers and oxidative stress. Forty-six C57BL/6J female mice were used, with initial ages between 4, 6 and 18 months, weighing about 25 - 28 grams, which constituted five groups: CT - animals that did not receive any treatment (6 months), SHAM - ovariectomy dummy (4 months), OVX – submitted to ovariectomy (4 months), VCD – medicated with 4-vinylcyclohexene diepoxide (VCD) (4 months) at a dose of 160 mg/kg/day, via IP for 20 consecutive days and ID – in the physiological post-estropause period (18 months). Once the condition of persistent diestrus was observed in the animals of all groups, they were submitted to extraction of the upper right incisor for later euthanasia in the periods of 7 and 21 days, when the jaws containing the alveoli were removed to obtain histological slides stained with HE, Goldner trichrome and for the immunohistochemical technique for RANKL and OPG proteins. Blood was also collected for biochemical analysis to measure calcium, phosphate, alkaline phosphatase (FAL) and total TRAP levels, as well as for total antioxidant capacity and TBARs. Histopathological analysis revealed that all alveoli repaired at 21 days; however, with differences in histomorphological aspects between the groups. The Control and SHAM groups showed regular bone trabeculation and remodeling with moderate staining for RANKL and OPG. On the other hand, the OVX and Elderly groups presented irregular and thin bone trabeculae from day 7, which showed little cellularization at day 21. The VCD group exhibited more discrete neoformation at 7 days, however, with bone tissue in clear remodeling at 21 days. Despite these differences, moderate staining for RANKL and OPG was observed in these groups, with emphasis on the mononuclear inflammatory infiltrate. The serum levels of TRAP and FAL were significantly increased in the Elderly group at 21 days compared to the other groups, as well as the total antioxidant capacity. No statistical differences were observed in calcium and phosphate levels, and in TBARs. From the results obtained, it can be concluded that the different models of ovarian failure, physiological or early, interfere differently in post-extraction alveolar bone repair, as well as in the serum levels of bone remodeling and antioxidant capacity markers, and should be considered at the time of model selection and correlation with clinical findings in humans. (AU)

• FAPESP's process: 20/07999-7 - Comparative analysis of alveolar intramembranous bone repair in female C57BL/6 mice under stropause chemically induced by ovariectomy and aging
• Grantee: Ana Carolina Zucon Bacelar Marcolino
• Support Opportunities: Scholarships in Brazil - Master