Aumento del daño en el ADN espermático en varones mayores de 40 años / Association of age with sperm DNA fragmentation

Background: There is an association between aging ana an increased number ofsperms with alterations in nuclear DNA. Aim: To study the association between age and fragmentation of sperm DNA. Material andMethods: Sixty two volunteers provided semen for analysis. These were separated in a group aged less than forty years and a second group aged more than forty years. Sperm DNA fragmentation was studied by TÚNEL (terminal deoxynucleotidyl transferase-mediated2'-deoxyuridine 5'-triphosphate nick end-labeling) and SCD (sperm chromatin dispersión test) assays. Results: Compared with theiryounger counterparts, patients aged more than 40years had a higher proportion ofsperms with DNA fragmentation by TÚNEL (20 ±1.3 and24 ± 1.9 percent respectively, p < 0.05) and SCD (22 ± 1.4 and26 ± 1.6 percent respectively, p < 0.05). The results ofboth assays had a correlation coefficientofO.8. No differences between groups were observed for other seminal parameters. Conclusions: Sperm DNA fragmentation increases with age in males.

Effect of embryo density and growth factors on in vitro preimplantation development of mouse embryos

Embryo development depends on maternal and embryonic factors that may regulate genetic programs in early development. Effects of growth factors on proliferation, differentiation and morphogenesis along embryogenesis have been documented. However, studies have not established the role of growth factors in the preimplantational period. The purpose of this study was to investigate the possible effects of growth factors and embryo density on mouse preimplantation development in vitro. Two-and eight-cell CF-1 embryos were cultured individually or in groups of ten in HTF medium, alone or with EGF, TGF-beta1 and IGF-I. Cleavage rate varied greatly with growth factors and increased significantly when eight-cell embryos were cultured in groups. On the other hand, when two-cell embryos were cultured in group, the cleavage rate was slower than that obtained when embryos were individually cultured. The differentiation rate increased significantly in two-cell embryos cultured in groups (p<0.05). EGF, TGF-beta1 and IGF-I increased differentiation rates significantly in two-cell embryos individually cultured for 68 hours. The combination of EGF and TGF-beta1 increased the differentiation rates significantly. The other combinations were not effective in modifying this parameter. Hatching rates increased in embryos cultured in groups (p<0.05). TGF-beta1 decreased this parameter significantly in two-or eight-cell embryos cultured in groups (p<0.05). The data described in this report suggest that preimplantational mouse embryos produce some factor or factors that enhance its development, specially the differentiation and hatching rates. However, a functional role for polypeptide growth factors during preimplantational development has to be determined.