Efeito do estresse térmico testicular na atividade mitocondrial e fragmentação de DNA de espermatozoides murinos
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Data
2024-05-09
Autores
Miyazaki, Mika Alexia [UNIFESP]
Orientadores
Bertolla, Ricardo Pimenta [UNIFESP]
Tipo
Dissertação de mestrado
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Objetivo: Simular a hipertermia testicular transitória e verificar se as alterações funcionais persistem nos espermatozoides após um ciclo completo de espermatogênese. Métodos: Foram utilizados 22 camundongos machos da linhagem C57BL/6 distribuídos em três grupos: Controle (n=7), Estresse térmico (n=7) e Sham (n=8). Para o grupo de estresse térmico, os animais foram sedados e a terça parte inferior do corpo (bolsa testicular, membros posteriores e cauda) foram imersas em banho de água a 40°C± 0.5ºC por 30 minutos por 6 dias consecutivos. O grupo Sham foi submetido ao mesmo protocolo, entretanto em temperatura a 33 °C± 0.5ºC. Após 35 dias do último dia de hipertermia testicular, os animais foram eutanasiados e da cauda do epidídimo foram coletados espermatozoides utilizados para mensuração da concentração, análise de fragmentação de DNA e atividade mitocondrial. Para a análise estatística, foi verificada a normalidade da distribuição dos dados pelo teste de Kolmogorov-Smirnov. Então, os grupos os controle, estresse térmico e sham foram comparados pela Análise de Variancia (ANOVA), seguido do teste post hoc LSD de Fisher quando verificado diferença estatística entre os grupos. Um erro alfa (α) de 5% foi adotado. Resultados: No presente estudo, não foi observada diferença estatísticamente significativa entre os grupos em relação a concentração espermática recuperada. Entretanto, foi revelado maior fragmentação de DNA e baixa atividade mitocondrial nos espermatozoides após 35 dias da finalização do estímulo. Conclusões: O modelo de estresse térmico aplicado neste estudo resultou em espermatozoides com função alterada.
Objective: To simulate transient testicular hyperthermia and investigate whether functional alterations persist in spermatozoa after a complete cycle of spermatogenesis. Methods: Twenty-two male C57BL/6 mice were divided into three groups: Control (n=7), Heat stress (n=7), and Sham (n=8). For the heat stress group, animals were sedated, and the lower third of the body (scrotum, hind limbs, and tail) was immersed in a water bath at 40°C± 0.5ºC for 30 minutes for 6 consecutive days. The Sham group underwent the same protocol, but at a temperature of 33°C± 0.5ºC. Thirty-five days after the last day of testicular hyperthermia, animals were euthanized, and spermatozoa were collected from the cauda epididymis for measurement of concentration, analysis of DNA fragmentation, and mitochondrial activity. Normality of data distribution was assessed using the Kolmogorov-Smirnov test. Subsequently, the control, heat stress, and sham groups were compared using Analysis of Variance (ANOVA), followed by Fisher's LSD post hoc test when statistical differences were observed between groups. A significance level (α) of 5% was adopted. Results: In the present study, no statistically significant difference was observed between groups regarding recovered sperm concentration. However, increased DNA fragmentation and decreased mitochondrial activity were revealed in spermatozoa 35 days after the end of the stimulus. Conclusions: The heat stress model applied in this study resulted in spermatozoa with altered function.
Objective: To simulate transient testicular hyperthermia and investigate whether functional alterations persist in spermatozoa after a complete cycle of spermatogenesis. Methods: Twenty-two male C57BL/6 mice were divided into three groups: Control (n=7), Heat stress (n=7), and Sham (n=8). For the heat stress group, animals were sedated, and the lower third of the body (scrotum, hind limbs, and tail) was immersed in a water bath at 40°C± 0.5ºC for 30 minutes for 6 consecutive days. The Sham group underwent the same protocol, but at a temperature of 33°C± 0.5ºC. Thirty-five days after the last day of testicular hyperthermia, animals were euthanized, and spermatozoa were collected from the cauda epididymis for measurement of concentration, analysis of DNA fragmentation, and mitochondrial activity. Normality of data distribution was assessed using the Kolmogorov-Smirnov test. Subsequently, the control, heat stress, and sham groups were compared using Analysis of Variance (ANOVA), followed by Fisher's LSD post hoc test when statistical differences were observed between groups. A significance level (α) of 5% was adopted. Results: In the present study, no statistically significant difference was observed between groups regarding recovered sperm concentration. However, increased DNA fragmentation and decreased mitochondrial activity were revealed in spermatozoa 35 days after the end of the stimulus. Conclusions: The heat stress model applied in this study resulted in spermatozoa with altered function.
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Citação
MIYAZAKI, Mika Alexia. Efeito do estresse térmico testicular na atividade mitocondrial e fragmentação de DNA de espermatozoides murinos. 2024. 60 f. Dissertação (Mestrado em Urologia) - Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP). São Paulo, 2024..