SYNCHRONOUS ASSESSMENT OF SPERM MOTILITY AND FERTILIZING ABILITY IN THE HAMSTER FOLLOWING TREATMENT WITH ALPHA-CHLOROHYDRIN

To investigate the relationship between sperm motion parameters and fe rtilizing ability, a model was developed to assess both of these endpo ints synchronously using a toxicant that inhibits sperm motion. alpha- Chlorohydrin (ACH) was administered daily for 4 days to male hamsters at 0, 33, 49, 66, and 83 mg/kg body weight, These males were then allo wed a 45-minute breeding period with untreated estrus females on the m orning of day 5. One hour after breeding, sperm samples were surgicall y recovered from the uteri of the females for motility analysis. Six h ours later, eggs were flushed from the oviducts and evaluated for fert ilization. Cauda epididymal sperm were also collected from the males s hortly after breeding. Proportions of motile and progressively motile sperm were manually quantified, and overall sperm velocity and the vel ocity of representative vigorously swimming sperm in both the uterine and epididymal samples were measured by computer-aided sperm analysis. Significant decreases in in vivo fertilization rates and epididymal s perm motion parameters were observed at 66 and 83 mg/kg ACH, whereas u terine sperm motion was adversely affected at all ACH dosages used. Al l sperm motion parameters except the percentage of motile sperm in the epididymis were significantly correlated with fertilization rates by both linear and logistic regression. Overall, uterine and epididymal s perm endpoints predicted fertilizing ability comparably well. Stepwise multiple linear regression gave a model containing epididymal sperm v elocity (EVCL) and uterine sperm percent motility (UMOT) with an R(2) value of 0.649. Stepwise multiple logistic regression gave models cont aining EVCL alone and EVCL and UMOT in binary (fertile/infertile) and quantal models, respectively.