Simple Methods for Objective Assessment of Sperm Viability and Motility with MTT Assay and Sperm Quality Analyzer (SQA) in Rats

To confirm the applicability of MTT assay and sperm quality analyzer (SQA) to the examination of sperm viability and motility in rats, epididymal spermatozoa derived from male rats (Slc:SD) treated with nitrobenzene at a dose of 60 mg/kg/day for 16 days were examined by these methods. Epididymal fluid was suspended in Dulbecco's modified Eagle's medium containing 25 mM fructose in ratio of 1:125. Sperm concentrations in the epididymal fluid were 2.48 ± 0.55 (× 106/μl, mean ± SD, n = 8) in the control and 2.20 ± 0.54 in the nitrobenzene group, and did not significantly differ between the groups. Both absorbance unit of the MTT assay (1.497 ± 0.406 vs. 1.084 ± 0.350) and SMI (sperm motility index) value of the SQA (204.0 ± 15.3 vs. 182.5 ± 21.6) were significantly decreased in nitrobenzene group. The results suggest that the examinations of sperm viability and motility with MTT assay and SQA are available for the reproductive toxicology in rats.