Effects of male accessory sex glands on sperm decondensation and oocyte activation during in vivo fertilization in golden hamsters

Removal of paternal male accessory sex glands (ASG) could cause a delay in DNA synthesis in hamster zygotes fertilized in vivo. In view of the fact th at this process is closely related to pronuclear development which, in part , depends on sperm nuclear decondensation and oocyte activation during fert ilization, we carried out a series ol experiments were undertaken to determ ine whether ASG also has an effect on these early events. (1) Oocytes were collected ham females mated with SH (sham-operated control), AGX (bilateral excision of ampullary glands), VPX (bilateral excision of ventral prostate s) or TX (excision of all ASG) males (n = 8 per group) at 4, 5 and 6 h post coitus. (2) Epididymal spermatozoa were incubated with total ventral prost ate (VP) secretion to study its effect on dithiothreitol-induced sperm deco ndensation. (3) Histone H-1 kinase activity in oocytes collected as describ ed in (1) was determined. (4) Exocytosed cortical granules on oocytes were labelled with FITC-LCA and quantified by a Metamorph Imaging System. Result s showed that sperm decondensation and resumption of meiosis in oocytes in VPX and TX groups were significantly slower compared with SH. VP secretion augmented sperm decondensation in vitro. At 4 h post coitus, the relative a ctivity of histone H1 kinase in the TX and VPX groups was significantly hig her than that in the SH group (p < 0.01). Cortical granule exocytosis in th e AGX group was consistently weaker at all time points studied and was sign ificantly lower than that of the control at 4 h post coitus (p < 0.05), whi le the percentage of polyspermic fertilization in the AGX group was signifi cantly higher compared with that in the SH group (p < 0.05). Taken together , these results show that the lack of exposure of spermatozoa to secretions of the ASC does not jeopardize their ability to penetrate ova, although ot her aspects of their function in the early stages of gamete interaction and subsequent initiation of embryonic development are affected.