H Bastiaan1, D Franken, P Wranz. 1. Department of Obstetrics & Gynaecology, University of Stellenbosch, Tygerberg Hospital, South Africa.
Abstract
PURPOSE: The study aimed to evaluate the (i) regulatory role of Gi-like protein during the acrosome reaction (AR) of normal sperm donors and (ii) the role of intact acrosomes during sperm-zona binding. METHODS: The acrosomal exocytosis of spermatozoa incubated with solubilized zona pellucida (ZP) at a final concentration of 1 ZP/microliter was compared with 10 microM calcium ionophore A23187 and 30% (v/v) pooled human follicular fluid (HFF). Spermatozoa were incubated with 1, 10, and 100 ng/ml pertussis toxin (PT) during capacitation to functionally inactivate the Gi-like protein. The sperm-zona binding potential of 100 ng/ml PT-treated spermatozoa followed, by exposure to 1 ZP/microliter, revealed significantly higher zona-bound spermatozoa compared to controls treated with 1 ZP/microliter only. RESULTS: PT treatment of spermatozoa did not affect sperm motility, however, inhibited the percentage AR induced by solubilized ZP. In contrast, the A23187- and HFF-induced ARs were not sensitive to PT treatment. PT inhibition of the ZP-induced AR occurred in a concentration-dependent manner, with maximal effects observed at 100 ng/ml PT. CONCLUSIONS: In conclusion, it seems that PT-sensitive Gi-like protein in human spermatozoa plays an important regulatory role in the AR induced by the human ZP, and this underlines the importance of intact acrosomes during sperm-zona binding.
PURPOSE: The study aimed to evaluate the (i) regulatory role of Gi-like protein during the acrosome reaction (AR) of normal sperm donors and (ii) the role of intact acrosomes during sperm-zona binding. METHODS: The acrosomal exocytosis of spermatozoa incubated with solubilized zona pellucida (ZP) at a final concentration of 1 ZP/microliter was compared with 10 microM calcium ionophore A23187 and 30% (v/v) pooled human follicular fluid (HFF). Spermatozoa were incubated with 1, 10, and 100 ng/ml pertussis toxin (PT) during capacitation to functionally inactivate the Gi-like protein. The sperm-zona binding potential of 100 ng/ml PT-treated spermatozoa followed, by exposure to 1 ZP/microliter, revealed significantly higher zona-bound spermatozoa compared to controls treated with 1 ZP/microliter only. RESULTS: PT treatment of spermatozoa did not affect sperm motility, however, inhibited the percentage AR induced by solubilized ZP. In contrast, the A23187- and HFF-induced ARs were not sensitive to PT treatment. PT inhibition of the ZP-induced AR occurred in a concentration-dependent manner, with maximal effects observed at 100 ng/ml PT. CONCLUSIONS: In conclusion, it seems that PT-sensitive Gi-like protein in human spermatozoa plays an important regulatory role in the AR induced by the human ZP, and this underlines the importance of intact acrosomes during sperm-zona binding.
Authors: Catherine Patrat; Jana Auer; Patricia Fauque; Roger L Leandri; Pierre Jouannet; Catherine Serres Journal: BMC Dev Biol Date: 2006-12-05 Impact factor: 1.978