Effects of glass-ceramic produced by the sol-gel route in macrophages recruitment and polarization into bone tissue regeneration.

Effective bone substitute biomaterials remain an important challenge in patients with large bone defects. Glass ceramics produced by different synthesis routes may result in changes in the material physicochemical properties and consequently affect the success or failure of the bone healing response. To investigate the differences in the orchestration of the inflammatory and healing process in bone grafting and repair using different glass-ceramic routes production. Thirty male Wistar rats underwent surgical unilateral parietal defects filled with silicate glass-ceramic produced by distinct routes: BS - particulate glass-ceramic produced via the fusion/solidification route, and BG - particulate glass-ceramic produced via the sol-gel route. After 7, 14, and 21 days from biomaterial grafting, parietal bones were removed to be analyzed under H&E and Massons' Trichome staining, and immunohistochemistry for CD206, iNOS, and TGF-ß. Our findings demonstrated that the density of lymphocytes and plasma cells was significantly higher in the BS group at 45, and 7 days compared to the BG group, respectively. Furthermore, a significant increase of foreign body giant cells (FBGCs) in the BG group at day 7, compared to BS was found, demonstrating early efficient recruitment of FBGCs against sol-gel-derived glass-ceramic particulate (BS group). According to macrophage profiles, CD206+ macrophages enhanced at the final periods of both groups, being significantly higher at 45 days of BS compared to the BG group. On the other hand, the density of transformation growth factor beta (TGF-ß) positive cells on 21 days were the highest in BG, and the lowest in the BS group, demonstrating a differential synergy among groups. Noteworthy, TGF-ß+ cells were significantly higher at 21 days of BG compared to the BS group. Glass-ceramic biomaterials can act differently in the biological process of bone remodeling due to their route production, being the sol-gel route more efficient to activate M2 macrophages and specific FBGCs compared to the traditional route. Altogether, these features lead to a better understanding of the effectiveness of inflammatory response for biomaterial degradation and provide new insights for further preclinical and clinical studies involved in bone healing.

Dose-response effect of Montelukast on post-extraction dental socket repair and skeletal phenotype of mice.

Bone metabolism and repair are directly regulated by arachidonic acid metabolites. At present, we analyzed the dose-response effects of a selective cysteinyl leukotriene receptor type-1 antagonist during bone repair after tooth extraction and on non-injured skeleton. Sixty-three 129 Sv/Ev male mice composed the groups: C-Control (saline solution); MTK2-2 mg/Kg of Montelukast (MTK) and MTK4-4 mg/Kg of MTK, daily administered by mouth throughout all experimental periods set at 7, 14, and 21 days post-operative. Dental sockets were analyzed by computed microtomography (microCT), histopathology, and immunohistochemistry. Femurs, L5 vertebra and organs were also removed for observation. Blood was collected for plasma bone and liver markers. Histopathology and microCT analysis revealed early socket repair of MTK2 and MTK4 animals, with significant increased BV/TV at days 14 and 21 compared to C. Higher plasma calcium was detected at days 7 and 21 in MTK4 in comparison to C, while phosphate was significantly increased in MTK2 in the same periods in comparison to C and MTK4. No significant differences were found regarding plasma ALP and TRAP, neither for local TRAP and Runx2 immunolabeling at the healing sockets. Organs did not present histological abnormalities. Increased AST levels have been detected in distinct groups and periods. In general, femur phenotype was improved in MTK treated animals. Collectively, MTK promoted early bone formation after tooth extraction and increased bone quality of femurs and vertebra in a time-dose-dependent manner, and should be considered as an alternative therapy when improved post-extraction socket repair or skeleton preservation is required.

Análise comparativa do reparo alveolar em camundongos fêmeas C57BL/6 em falência ovariana provocada pela senescência, induzida quimicamente ou por ovariectomia / Comparative analysis of alveolar repair in female C57BL/6 mice in ovarian failure caused by senescence, chemically induced or by ovariectomy

Diferentes modelos animais são utilizados para investigação do metabolismo e reparo ósseo pós-menopausa, resultando em diferentes impactos na produção dos hormônios ovarianos. O presente trabalho analisou e comparou o processo de reparo ósseo intramembranoso após a extração dentária de camundongos fêmeas em condição de estropausa fisiológica, induzida quimicamente e por ovariectomia, bem como os níveis séricos de marcadores ósseos e de estresse oxidativo. Foram utilizados 46 camundongos fêmeas C57BL/6J, com idades iniciais entre 4, 6 e 18 meses, pesando cerca de 25 - 28 gramas, as quais constituíram cinco grupos: CT ­ animas que não receberam nenhum tratamento (6 meses), SHAM ­ ovariectomia fictícia (4 meses), OVX ­ submetidas a ovariectomia (4 meses), VCD ­ medicadas com diepóxido 4-vinilciclohexeno (VCD) (4 meses) na dose de 160 mg/Kg/dia, via IP por 20 dias consecutivos e ID ­ em período pós-estropausa fisiológica (18 meses). Constatada a condição de diestro persistente nos animais de todos os grupos, os mesmos foram submetidos a exodontia do incisivo superior direito para posterior eutanásia nos períodos de 7 e 21 dias, quando as maxilas contendo os alvéolos foram removidas para obtenção de lâminas histológicas coradas com HE, Tricrômico de Goldner e para a técnica imuno-histoquímica para as proteínas RANKL e OPG. O sangue também foi coletado para as análises bioquímicas para dosagem dos níveis de cálcio, fosfato, fosfatase alcalina (FAL) e TRAP total, bem como para capacidade antioxidante total e TBARs. A análise histopatológica revelou que todos os alvéolos repararam aos 21 dias; porém, com diferenças nos aspectos histomorfológicos entre os grupos. Os grupos Controle e SHAM apresentaram trabeculado ósseo regular e em remodelação com moderada marcação para RANKL e OPG. Já os grupos OVX e Idosa apresentaram trabéculas ósseas irregulares e delgadas desde o dia 7, as quais mostravam-se pouco celularizadas aos 21 dias. O grupo VCD exibiu neoformação mais discreta aos 7 dias, porém, com tecido ósseo em franca remodelação aos 21 dias. Apesar destas diferenças, notou-se moderada marcação para RANKL e OPG nestes grupos, com destaque para o infiltrado inflamatório mononuclear. Os níveis séricos de TRAP e FAL estavam significativamente aumentados no grupo Idosa aos 21 dias em comparação com os demais grupos, bem como a capacidade antioxidante total. Não foram observadas diferenças estatísticas nos níveis de cálcio e fosfato, e em TBARs. A partir dos resultados obtidos pode-se concluir que os diferentes modelos de falência ovariana, fisiológica ou precoce, interferem de modo distinto no reparo ósseo alveolar pós-exodontia, bem como nos níveis séricos nos marcadores de remodelação óssea e de capacidade antioxidante, devendo ser considerados no momento da seleção do modelo e correlação com os achados clínicos em humanos(AU)

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. Fortysix 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)