Abstract
The in vitro capacitation and fertilizing ability of epididymal spermatozoa of BALB/c and ICR mice were compared. The capacitation rate of spermatozoa from BALB/c was significantly (P<0.05) lower than that of those from ICR mice when examined by chlortetracycline (CTC) fluorescence assay after 1 and 2 h of preincubation. An in vitro fertilization technique has revealed that the time taken for sperm penetration into intact and zona-free eggs was longer for BALB/c than for ICR spermatozoa (P<0.01). Fertilization rates for spermatozoa from BALB/c mice were significantly (P<0.01) lower than for spermatozoa from ICR regardless of the type of eggs (BALB/c, ICR). These results suggest that the low fertilizing ability of epididymal spermatozoa from BALB/c mice is associated with a lower efficiency of capacitation in vitro.
