Bibliographic citations
Vásquez, J., (2012). Fisiología espermática, fragmentación del ADN y niveles de expresión génica de Prm1, Prm2, Tnp1 y Tnp2 en relación a la edad en ratones [Tesis, Universidad Nacional Mayor de San Marcos]. https://hdl.handle.net/20.500.12672/2671
Vásquez, J., Fisiología espermática, fragmentación del ADN y niveles de expresión génica de Prm1, Prm2, Tnp1 y Tnp2 en relación a la edad en ratones [Tesis]. PE: Universidad Nacional Mayor de San Marcos; 2012. https://hdl.handle.net/20.500.12672/2671
@misc{sunedu/4332749,
title = "Fisiología espermática, fragmentación del ADN y niveles de expresión génica de Prm1, Prm2, Tnp1 y Tnp2 en relación a la edad en ratones",
author = "Vásquez Cavero, Jonathan Humberto",
publisher = "Universidad Nacional Mayor de San Marcos",
year = "2012"
}
--- Age has an influence in the proper packaging of sperm chromatin, rendering it more vulnerable as time goes on. Protamines are the most abundant nuclear proteins in the mature spermatozoon and they are responsible for packing the paternal genome inside the sperm cell nucleus, making it inaccessible to nucleases or mutagens, thus protecting it. Mice with only one copy of these genes are infertile, which proves that are essential for normal spermatic function. The aim of this study was to look for a correlation between male age and sperm protamination at molecular and physiological levels. Male mice (Mus musculus Linnaeus, 1758) from C57BLACK6 (C57BL6) strain (20-25g) were used and distributed in two age groups: 3-4 month old mice ("Young" group: G1) and 18-21 month old ("Elderly" group: G2). Spermatozoa obtained from the epididymis tail were employed in sperm motility analysis, DNA fragmentation analysis by bidimensional comet assay, and oxidative stress by TBARS assay. Testicular tissue was used for assess the gene expression of Prm1, Prm2, Tnp1 and Tnp2, by real time PCR (RT-qPCR). When analyzing sperm motility, MOT (50.63 ± 6.60% vs 30.38 ± 5.16 %) and MR (24.50 ± 3.04 % vs 13.92 ± 3.02 %) were higher in G1 compared to G2 (p<0.05). However, ME was higher in G2 compared to G1 (69.31 ± 5.31 % vs 48.38 ± 7.39 %, respectively) (p<0.05). Likewise, when analyzing displacement types in the sperm cells, VAP (67.89 ± 5.68 % vs 52.12 ± 3.38 %, p<0.05) and VSL (43.15 ± 3.47 % vs 30.68 ± 2.45 %, p<0.05) were higher in G1 compared to G2. Oxidative stress levels measured by TBARS did not show any differences between G1 and G2 (132.50 ± 9.64 ng MDA/106 spz vs 135.00 ± 10.81 ng MDA/106 spz; p>0.05). The proportion of sperm cells with fragmented DNA were not significantly different (G1 vs G2, 20.51 ± 1.41 % vs 20.11 ± 1.29 % respectively, p>0.05) and there were also no differences in the percentage of fragmented DNA of those subpopulations (17.36 ± 0.49 % vs 17.76 ± 0.62 %, p>0.05). Gene expression levels of Prm2 and Tnp1 were significantly overexpressed in G2 in comparison to G1 (p<0.05); however, Prm1 and Tnp2 did not show significant differences between both groups (p<0.05). Despite of age had an influence in expression levels of Prm2 and Tnp1, it would not be relevant enough to alter ROS production and sperm DNA fragmentation. It was probably due to the central role of Prm1 in sperm protamination, something widely reported in all studied species to date, which levels were not altered in the elderly group. As a conclusion, increase of age does not alter sperm protamination in mice.
This item is licensed under a Creative Commons License