Effect of Heat Stress on Sperm DNA: Protamine Assessment in Ram Spermatozoa and Testicle

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dos Santos Hamilton, Thais Rose ; Perez Siqueira, Adriano Felipe ; de Castro, Leticia Signori ; Mendes, Camilla Mota ; Delgado, Juliana de Carvalho ; de Assis, Patricia Monken ; Mesquita, Leonardo Pereira ; Maiorka, Paulo Cesar ; Nichi, Marcilio ; Goissis, Marcelo Demarchi ; Visintin, Jose Antonio ; Avila Assumpcao, Mayra Elena Ortiz D.

• Tipo de documento: Artigo Científico
• Fonte: OXIDATIVE MEDICINE AND CELLULAR LONGEVITY; v. 2018, p. 14-pg., 2018-01-01.

Resumo

Sperm DNA fragmentation is considered one of the main causes of male infertility. The most accepted causes of sperm DNA damage are deleterious actions of reactive oxygen species (ROS), defects in protamination, and apoptosis. Ram sperm are highly prone to those damages due to the high susceptibility to ROS and to oxidative stress caused by heat stress. We aimed to evaluate the effects of heat stress on the chromatin of ejaculated and epididymal sperm and the activation of apoptotic pathways in different cell types in ram testis. We observed higher percentages of ejaculated sperm with increased chromatin fragmentation in the heat stress group; a fact that was unexpectedly not observed in epididymal sperm. Heat stress group presented a higher percentage of spermatozoa with DNA fragmentation and increased number of mRNA copies of transitional protein 1. Epididymal sperm presented greater gene expression of protamine 1 on the 30th day of the spermatic cycle; however, no differences in protamine protein levels were observed in ejaculated sperm and testis. Localization of proapoptotic protein BAX or BCL2 in testis was not different. In conclusion, testicular heat stress increases ram sperm DNA fragmentation without changes in protamination and apoptotic patterns. (AU)

• Processo FAPESP: 12/16157-3 - Identificação de células-tronco espermatogoniais indiferenciadas em bovinos
• Beneficiário: Marcelo Demarchi Goissis
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/05025-1 - Mensuração das enzimas antioxidantes no sêmen de ovinos: concentrações plasmáticas e celulares
• Beneficiário: Thais Rose dos Santos Hamilton
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 11/11231-8 - Estudo dos fatores envolvidos na fragmentação de DNA dos espermatozóides em ovinos.
• Beneficiário: Thais Rose dos Santos Hamilton
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/19551-1 - Relação entre o tipo de protaminação e a atividade das endonucleases na proteção do DNA espermático bovino
• Beneficiário: Mayra Elena Ortiz D' Avila Assumpcao
• Modalidade de apoio: Auxílio à Pesquisa - Regular