J. Zhang et al., ZONA-OPENING OF HAMSTER OOCYTES - A COMPARATIVE-STUDY USING MACRO-MANIPULATION AND MICRO-MANIPULATION METHODS, Human reproduction, 9(1), 1994, pp. 137-140
The present study compared a new macro-manipulation technique for zona
-opening of hamster oocytes with existing micro-manipulation technique
s. In experiment I the zona pellucida of hamster oocytes was partially
opened with a 32 gauge steel needle (macro-manipulation) and these oo
cytes were then co-incubated with human spermatozoa at 36.5 degrees C
in 5% CO2 in air for 3.5 h. Zona-free and zona-intact oocytes similarl
y inseminated served as controls. Of 113 oocytes, 30 (26%) lysed follo
wing zona-opening with the macro technique. The sperm penetration rate
s of zona-opened and zona-free oocytes were 37% (31/83) and 60% (49/81
) respectively (P < 0.01), with 12 and 28% oocytes respectively showin
g polyspermia (P < 0.05). No sperm penetration occurred in zona-intact
oocytes. In experiment II the zona pellucida of hamster oocytes was p
artially opened by macro- micro-manipulation techniques before the ooc
ytes were coincubated with human spermatozoa as in experiment I. Nine
of 156 (6%) macro-manipulated and 11 of 133 (8%) micro-manipulated ooc
ytes lysed following zona-opening. Of 147 remaining macro-manipulated
and 122 remaining micro-manipulated oocytes, 80 (55%) and 79 (64%) res
pectively were penetrated (P > 0.05), with 30 and 37% respectively sho
wing polyspermia (P > 0.05). These results demonstrate that macro-mani
pulation results in similar penetration and polyspermia rates as compa
red to conventional micro-manipulation.