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.

Efeito tempo-dose-resposta do montelucaste no processo de reparo alveolar em camundongos 129Sv/Ev / Time-dose-response effect of Montelukast in the process of alveolar repair in 129Sv / Ev mice

Metabólitos do ácido araquidônico são conhecidos por exercerem importante papel nos processos inflamatórios e no metabolismo do tecido ósseo. No entanto, as ações pontuais, especialmente dos leucotrienos derivados da 5-lipoxigenase (5-LO) sobre o processo de reparo ósseo intramembranoso são pouco exploradas. O presente estudo tem como objetivo analisar os efeitos tempo-dose-resposta da droga montelucaste (MTK), potente antagonista dos receptores de cisteinil leucotrienos tipo 1 (CisLT1Rs), no curso do reparo alveolar pós-exodontia em camundongos 129Sv/Ev, bem como nos níveis plasmáticos de marcadores ósseos bioquímicos. Para tanto, foram utilizados 70 camundongos machos jovens divididos em quatro grupos, de acordo com o tratamento: C - Grupo Controle (não tratados); CV - Grupo Controle Veículo, 20 µL de solução fisiológica (SF) 0,9%; MTK2 ­2 mg/kg de MTK e MTK4 ­ 4 mg/kg de MTK. Os animais dos grupos CV, MTK2 e MTK4 foram tratados diariamente por via oral, iniciando 24 horas antes do procedimento cirúrgico, continuando até o final dos períodos experimentais de 7, 14 e 21 dias pós-operatórios. Ao final dos períodos determinados, os animais foram submetidos à eutanásia para coleta de sangue para análise bioquímica dos níveis de cálcio, fosfato, fosfatase ácida resistente ao tartarato (TRAP) total e fosfatase alcalina (FAL), coleta da maxila direita contendo os alvéolos dentários para serem analisados por meio de microtomografia computadorizada (microCT), e análise histopatológica. Os resultados obtidos foram submetidos à testes estatísticos considerando-se nível de confiança de 5%. Observou-se aumento do BV/TV para os animais tratados com MTK em relação aos grupos C e CV, tanto aos 14 dias quanto aos 21 dias, sendo maior no grupo MTK4 aos 14 dias em relação ao grupo MTK2. Do mesmo modo, os animais tratados com MTK em ambas doses apresentaram aumento significativo de Tb.Th em comparação aos grupos C e CV aos 21 dias. Chamou a atenção valores de BV/TV e Tb.Th significativamente reduzidos no grupo CV em comparação ao C, indicando um efeito negativo da manipulação do animal. Na análise histopatológica observou-se reparo ósseo precoce nos animais MTK2 e MTK4 em todos os períodos avaliados, em comparação aos do grupo C, bem como atraso no processo de reparo no grupo CV aos 21 dias. Quanto aos marcadores plasmáticos, observou-se aumento do cálcio no grupo MTK4 em relação ao grupo C aos 7 dias, e aos 21 dias também em relação ao grupo MTK2. Já o fosfato mostrouse significantemente elevado nos períodos de 7 e 21 dias no grupo MTK2 em relação aos demais grupos. FAL e TRAP total não apresentaram níveis plasmáticos significativamente diferentes comparando-se os grupos e períodos. Considerando os resultados obtidos, concluiu-se que o MTK exerceu efeito tempo-dose-dependente, acelerando o processo de reparo ósseo intramembranoso alveolar e interferindo nos níveis plasmáticos de cálcio e fosfato no presente modelo animal(AU)

Arachidonic acid metabolites are known to play an important role in inflammatory processes and in bone metabolism. However, the role of these products on alveolar bone repair post tooth extraction remains to be explored, especially leukotrienes, derived from 5-lipoxygenase (5-LO). The present study aims to analyze the time-doseresponse effects of the drug montelukast (MTK), a potent type 1 leukotriene cystenyl antagonist (CisLT1Rs), in the alveolar repair process after extraction in male 129Sv/Ev mice. For this purpose, 70 young male mice were used, divided into four groups: C - Control Group (no treatment); VC - Vehicle Control Group, treated with 20 µL of 0.9% SF; MTK2 - treated with 2mg / Kg of MTK and MTK4 - treated with 4mg / Kg of MTK. The animals of the CV, MTK2 and MTK4 groups were treated daily orally (V.O.), starting 24 hours before the surgical procedure, continuing until the end of the experimental periods of 7, 14 and 21 days postoperatively. At the end of the experimental periods, the animals were euthanized for blood collection for serum markers as calcium, phosphate, tartrate-resistant acid phosphate (TRAP) and alkaline phosphatasis (FAL), and to removal of the right maxilla containing the dental socket to be analyzed under computed microtomography (microCT) and histopathology. The results obtained were subjected to statistical tests considering a confidence level of 5%. Results revealed an increase in BV/TV for MTK vs. C and CV groups, in both 14 and 21 days time points. Of note, this increase was higher in MTK4 than in the MTK2 at 14 days. Considering Tb.Th, both MTK2 e MTK4 groups presented positive effects in the BV/TV and Tb.Th increase when compared to controls groups (C and CV) at 21 days. A decrease in BV/TV and Tb.Th was observed in CV compared to C, as a negative effect of animal manipulation. As observed in H&E sections, both MTK2 and MTK4 experimental groups presented an early bone repair in comparison with C group from 7 to 21 days. CV group presented a slight delayed bone healing compared to C. Levels of calcium was increased in MTK4 in comparison to C and MTK2 at 7 and 21 days. Phosphate was significantly elevated at 7 and 21 days in MTK2 in comparison to the other groups. Despite of beneficial effects on observed on morphological levels on sites of healing (microCT and HE), no significant changes were found for bone markers of remodeling in blood plasma (FAL and TRAP). Taken together, these results indicate that MTK induced early bone healing post tooth extraction in 129Sv/Ev mice. Thus, the inhibition of CysLT is suggested to exert a positive influence on intramembranous bone repair post tooth extraction(AU)