Análise do fêmur de ratas tratadas com ocitocina e submetidas ao treinamento de força durante a periestropausa.
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Data
2021-12-16
Autores
Fernandes-Breitenbach, Fernanda [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A diminuição nas concentrações de estrógeno, como o que ocorre no período da perimenopausa e menopausa, contribui para o aumento do turnover ósseo, com taxa de reabsorção superior à de formação óssea que favorece a instalação da osteoporose, doença silenciosa que determina fragilidade óssea e maior probabilidade de fraturas. Entre as intervenções utilizadas para prevenção da osteoporose, destaca-se o treinamento de força (TF) e a ocitocina (OT), hormônio promissor com ação anabólica no osso. O objetivo deste estudo foi verificar a ação da associação da OT ao TF, em comparação às intervenções isoladas, no processo de remodelamento ósseo do colo do fêmur de ratas Wistar na periestropausa (18 a 21 meses). Quarenta ratas Wistar com ciclo estral irregular (18 meses) foram randomizadas nos grupos: 1-Veículo (Veh); 2-Ocitocina (Ot); 3-Treinamento de força (Tf); 4-Ot+Tf. Os animais do grupo 1 receberam salina (0,15 mol/L) e dos grupos 2 e 4 receberam OT (134 µg/kg), sendo duas injeções intraperitoneais com intervalo de 12 horas a cada 30 dias, totalizando 8 injeções ao final do período experimental. Os animais dos grupos 3 e 4 realizaram TF em escada 3 vezes por semana com realização mensal do teste de capacidade de carga máxima voluntária (CCMV). Após 120 dias, os animais foram eutanasiados, os fêmures foram coletados para análises de ensaio mecânico, densitometria, microtomografia óssea, espectroscopia de Raman e técnica de reação em cadeia da polimerase de transcrição reversa em tempo real (qRT-PCR), e o sangue para análises de marcadores bioquímicos do metabolismo ósseo, dano hepático e estresse oxidativo. A principal novidade deste estudo é a adição da OT ao TF, a qual apresentou, no ensaio de compressão, maior força máxima em relação ao Veh e menor elasticidade em relação ao Tf e, no ensaio de flexão de três pontos, maior rigidez em relação ao Veh e Ot, menor rigidez e menor elasticidade em relação ao Veh; maior espessura cortical (Ct.Th) em relação aos demais grupos, menor número de poros (Po.N) em relação ao Veh e Ot, e maior momento polar médio (J) em relação ao Tf. Houve também maior volume do osso trabecular (BV/TV) em relação ao Ot e maior espessura trabecular (Tb.Th) em relação aos demais grupos. A densidade mineral óssea areal (aDMO) do colo do fêmur foi maior que o Ot, e a DMO do fêmur total foi maior que os demais grupos. Quanto a expressão gênica, houve maior expressão do fator de transcrição relacionado ao Runt 2 (Runx2) em relação ao Veh, o fator de transcrição Osterix (Osx/Sp7) foi menor que o Ot e Tf. A proteína morfogenética óssea 2 (Bmp2) apresentou menor expressão em relação ao Veh, e a expressão da fosfatase alcalina óssea (Fal) foi maior que os demais grupos. A expressão do membro da família do fator de necrose tumoral 11b (Opg) e do ligante do fator de necrose tumoral (Rankl) foi maior que os outros grupos, a expressão do membro do fator de necrose tumoral 11a (Rank) e catepsina K (Ctsk) foi maior que Veh e Ot. Também foi observado menor atividade de fosfatase ácida resistente ao tartarato (TRAP) e capacidade antioxidante total (CAT) no ensaio bioquímico em relação aos demais grupos. Na intervenção com OT, houve maior elasticidade no ensaio de flexão de três pontos, e maior Ct.Th em relação ao Veh. A expressão gênica de Runx2, Osx/Sp7 foi maior e Bmp2 foi menor que o grupo Veh. No TF houve maior elasticidade que o Veh e Ot no ensaio de compressão, maior rigidez e elasticidade em relação ao Veh no ensaio de flexão de três pontos. Houve menor Ct.Th em relação ao Ot, maior DMO do fêmur total em relação ao Veh, e a taxa de mineralização foi maior que o Veh e Ot. Na expressão gênica, Runx2 e Osx/Sp7 foram maiores que o Veh. A Bmp2 e osteocalcina/proteína óssea gama-carboxiglutamato (Ocn) foram menores que o Veh, e a Fal foi menor que Ot. Em relação a Rank e Ctsk, estas foram maiores que Veh e Ot. Por fim, a atividade de aspartato aminotransferase (AST) foi menor que o Veh. Esses resultados mostraram que a associação de intervenções é estratégia anabólica promissora para a prevenção da osteoporose no período da periestropausa, destacando-se dos efeitos das intervenções isoladas, ao preservar aspectos mecânicos, estruturais e gênicos do osso, além de parecer controlar fatores relacionados ao cross-talk entre tecido ósseo e tecido adiposo a favor da homeostase oxidativa e de fatores relacionados a atividade de marcadores ósseos.
The decrease in estrogen concentrations, such as that which occurs during perimenopause and menopause, contributes to an increase in bone turnover, with a rate of resorption higher than that of bone formation, which favors the installation of osteoporosis, a silent disease that determines bone fragility and greater probability of fractures. Among the interventions used to prevent osteoporosis, strength training (ST) and oxytocin (OT), a promising hormone with anabolic action on bone, stand out. The objective of this study was to verify the action of the association of OT and ST, compared to isolated interventions, in the process of bone remodeling of the femoral neck of Wistar rats in periestropause (18 to 21 months). Forty Wistar rats with irregular estrous cycle (18 months) were randomized into groups: 1-Vehicle (Veh); 2-Oxytocin (Ot); 3-Strength training (St); 4-Ot+St. The animals in group 1 received saline (0.15 mol/L) and in groups 2 and 4 received OT (134 µg/kg), with two intraperitoneal injections with an interval of 12 hours every 30 days, totaling 8 injections at the end of the period. trial period. The animals in groups 3 and 4 performed ST on a ladder 3 times a week with monthly performance of the maximum voluntary carrying capacity test (MVCC). After 120 days, the animals were euthanized, the femurs were collected for mechanical assay analysis, densitometry, bone microtomography, Raman spectroscopy and real-time reverse transcription polymerase chain reaction (qRT-PCR) technique, and blood for analysis of biochemical markers of bone metabolism, liver damage and oxidative stress. The main novelty of this study is the addition of OT to ST, which presented, in the compression test, greater maximum force in relation to Veh and less elasticity in relation to St and, in the three-point bending test, greater stiffness in relation to to Veh and Ot, less rigidity and less elasticity in relation to Veh; greater cortical thickness (Ct.Th) in relation to the other groups, smaller number of pores (Po.N) in relation to Veh and Ot, and greater mean polar moment (J) in relation to St. There was also greater trabecular bone volume (BV/TV) in relation to Ot and greater trabecular thickness (Tb.Th) in relation to the other groups. The areal bone mineral density (aBMD) of the femoral neck was higher than the Ot, and the BMD of the total femur was higher than the other groups. As for gene expression, there was greater expression of the transcription factor related to Runt 2 (Runx2) in relation to Veh, the transcription factor Osterix (Osx/Sp7) was lower than Ot and St. Bone morphogenetic protein 2 (Bmp2) showed lower expression compared to Veh, and bone alkaline phosphatase (Alp) expression was higher than the other groups. The expression of tumor necrosis factor 11b family member (Opg) and tumor necrosis factor ligand (Rankl) was higher than the other groups, tumor necrosis factor 11a member (Rank) and cathepsin K (Ctsk) was greater than Veh and Ot. It was also observed lower activity of tartrate resistant acid phosphatase (TRAP) and total antioxidant capacity (CAT) in the biochemical assay in relation to the other groups. In the intervention with OT, there was greater elasticity in the three-point bending test, and greater Ct.Th in relation to Veh. The gene expression of Runx2, Osx/Sp7 was higher and Bmp2 was lower than the Veh group. In ST intervention there was greater elasticity than Veh and Ot in the compression test, greater stiffness and elasticity in relation to Veh in the three-point bending test. There was lower Ct.Th in relation to Ot, higher BMD of the total femur in relation to Veh, and the mineralization rate was higher than Veh and Ot. In gene expression, Runx2 and Osx/Sp7 were higher than Veh. Bmp2 and osteocalcin/bone protein gamma-carboxyglutamate (Ocn) were lower than Veh, and Fal was higher than Ot. In relation to Rank and Ctsk, these were higher than Veh and Ot. Finally, aspartate aminotransferase (AST) activity was lower than Veh. These results showed that the association of interventions is a promising anabolic strategy for the prevention of osteoporosis in the periestropause period, standing out from the effects of isolated interventions, by preserving mechanical, structural and genetic aspects of the bone, in addition to seeming to control factors related to the cross -talk between bone tissue and adipose tissue in favor of oxidative homeostasis and factors related to the activity of bone markers.
The decrease in estrogen concentrations, such as that which occurs during perimenopause and menopause, contributes to an increase in bone turnover, with a rate of resorption higher than that of bone formation, which favors the installation of osteoporosis, a silent disease that determines bone fragility and greater probability of fractures. Among the interventions used to prevent osteoporosis, strength training (ST) and oxytocin (OT), a promising hormone with anabolic action on bone, stand out. The objective of this study was to verify the action of the association of OT and ST, compared to isolated interventions, in the process of bone remodeling of the femoral neck of Wistar rats in periestropause (18 to 21 months). Forty Wistar rats with irregular estrous cycle (18 months) were randomized into groups: 1-Vehicle (Veh); 2-Oxytocin (Ot); 3-Strength training (St); 4-Ot+St. The animals in group 1 received saline (0.15 mol/L) and in groups 2 and 4 received OT (134 µg/kg), with two intraperitoneal injections with an interval of 12 hours every 30 days, totaling 8 injections at the end of the period. trial period. The animals in groups 3 and 4 performed ST on a ladder 3 times a week with monthly performance of the maximum voluntary carrying capacity test (MVCC). After 120 days, the animals were euthanized, the femurs were collected for mechanical assay analysis, densitometry, bone microtomography, Raman spectroscopy and real-time reverse transcription polymerase chain reaction (qRT-PCR) technique, and blood for analysis of biochemical markers of bone metabolism, liver damage and oxidative stress. The main novelty of this study is the addition of OT to ST, which presented, in the compression test, greater maximum force in relation to Veh and less elasticity in relation to St and, in the three-point bending test, greater stiffness in relation to to Veh and Ot, less rigidity and less elasticity in relation to Veh; greater cortical thickness (Ct.Th) in relation to the other groups, smaller number of pores (Po.N) in relation to Veh and Ot, and greater mean polar moment (J) in relation to St. There was also greater trabecular bone volume (BV/TV) in relation to Ot and greater trabecular thickness (Tb.Th) in relation to the other groups. The areal bone mineral density (aBMD) of the femoral neck was higher than the Ot, and the BMD of the total femur was higher than the other groups. As for gene expression, there was greater expression of the transcription factor related to Runt 2 (Runx2) in relation to Veh, the transcription factor Osterix (Osx/Sp7) was lower than Ot and St. Bone morphogenetic protein 2 (Bmp2) showed lower expression compared to Veh, and bone alkaline phosphatase (Alp) expression was higher than the other groups. The expression of tumor necrosis factor 11b family member (Opg) and tumor necrosis factor ligand (Rankl) was higher than the other groups, tumor necrosis factor 11a member (Rank) and cathepsin K (Ctsk) was greater than Veh and Ot. It was also observed lower activity of tartrate resistant acid phosphatase (TRAP) and total antioxidant capacity (CAT) in the biochemical assay in relation to the other groups. In the intervention with OT, there was greater elasticity in the three-point bending test, and greater Ct.Th in relation to Veh. The gene expression of Runx2, Osx/Sp7 was higher and Bmp2 was lower than the Veh group. In ST intervention there was greater elasticity than Veh and Ot in the compression test, greater stiffness and elasticity in relation to Veh in the three-point bending test. There was lower Ct.Th in relation to Ot, higher BMD of the total femur in relation to Veh, and the mineralization rate was higher than Veh and Ot. In gene expression, Runx2 and Osx/Sp7 were higher than Veh. Bmp2 and osteocalcin/bone protein gamma-carboxyglutamate (Ocn) were lower than Veh, and Fal was higher than Ot. In relation to Rank and Ctsk, these were higher than Veh and Ot. Finally, aspartate aminotransferase (AST) activity was lower than Veh. These results showed that the association of interventions is a promising anabolic strategy for the prevention of osteoporosis in the periestropause period, standing out from the effects of isolated interventions, by preserving mechanical, structural and genetic aspects of the bone, in addition to seeming to control factors related to the cross -talk between bone tissue and adipose tissue in favor of oxidative homeostasis and factors related to the activity of bone markers.
Descrição
Palavras-chave
Envelhecimento, Osteoporose, Fêmur, Ocitocina, Treinamento de força, Aging