Aging effect on protamination of mice sperm DNA

• Grant number: 18/01335-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2018
• End date: July 15, 2018
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: Mayra Elena Ortiz D' Avila Assumpcao
• Grantee: Kauê Ribeiro da Silva
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Males present an important role in determination of fecundity, early embryo development and development of congenital diseases. In order to execute the function of carrying the genetic material to the oocyte, the sperm has its genome protected during spermatogenesis. Such protection is mainly mediated by protamination of its DNA. Researches show that there is a higher fragmentation of DNA in older men and this may be due to deficiency on protamination (causing DNA to be more susceptible to fragmentation), but there is inconsistency of results relating to whether or not fertility is lowered while aging. In order to study the influence of paternal age on fertility and effects of aging on sperm biology, two groups of male mice, separated by age (younger, 4 months, and older, more than 1.5 years), will be compared regarding protamination of sperm DNA. These animals will be euthanized for semen collect from caudal epididymis, and samples of each groups will be used for: 1) protemines (PRM) 1 and 2 and transitional proteins (TNP) 1 e 2 gene expression evaluation. 2) protein expression by Western Blottingand 3) protamination degree by CMA3 staining. Considering that: older animals may have lower fertility, and protamination is one of the factors that protects sperm DNA from fragmentation, it is expected that protamination is lowered in the group of older animals and this would represent one of the factors for the lower fertility and emergence of diseases on the offspring, when comparing these results to humans. (AU)