Murine sperm capacitation, oocyte penetration and decondensation following moderate alcohol intake

Abstract

Male chronic alcohol abuse causes testicular failure and infertility. We analyzed the effects of moderate sub-chronic alcohol intake on sperm morphology, capacitation, fertilization and sperm head decondensation. CF-1 male mice were administered 15% ethanol in drinking water for 15 days; control mice received ethanol-free water. Similar patterns of tyrosine phosphorylation were observed in capacitated spermatozoa of control and treated males. Percentage of hyperactivation (H) and spontaneous (SAR) and progesterone-induced (IAR) acrosome reaction significantly decreased at 120 and 150 min of capacitation in treated males compared to controls (H: 14.1 ± 2.5 vs 23.7 ± 2.6, P < 0.05; SAR-T120 min: 17.9 ± 2.5 vs 32.9 ± 4.1, P < 0.01; IAR-150 min: 43.3 ± 3.5 vs 73.1 ± 1.1, P < 0.001, n = 6). During in vitro fertilization (2.5, 3.5 and 4.5 h post-insemination), there was an increased percentage of fertilized oocytes (with a decondensed sperm head and one or two pronuclei) in treated males (P < 0.001, n = 7). After 60 min of in vitro decondensation with glutathione plus heparin, the percentage of decondensed sperm heads was significantly higher in treated males than in controls (mean ± s.d.: 57.1 ± 5.6 vs 48.3 ± 4.5, P < 0.05, n = 5). The percentage of morphologically normal sperm heads was significantly decreased in treated males with respect to controls (P < 0.001, n = 9). These results show that short-term moderate alcohol consumption in outbred mice affect sperm morphology, hyperactivation, acrosomal exocytosis, and the dynamics of in vitro fertilization and in vitro sperm nuclear decondensation.