Sperm MTT viability assay: A new method for evaluation of human sperm viability

Purpose: MTT (3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay is commonly used as a cell proliferation assay. The objective of this study was to evaluate the capability of MTT assay to discriminate between viable and nonviable sperms and compare its efficiency with E&N (eosin and nigrosin) and HOST (hypo-osmotic swelling test). Methods: MTT assay was modified to obtain optimal result for assessment of sperm viability. After standardization of method, MTT, E&N, and HOST were carried out simultaneously on 57 semen samples from patients referring to Isfahan Fertility and Infertility Center. The correlation coefficient between these tests and sperm motility was calculated using the SPSS statistical program. Specificity and sensitivity of each test was also obtained. Results: The optimal conditions for sperm MTT viability assay were 2 h after addition of sperm to MTT in HAM'S F10 C 25 mM HEPES + 10% HSA at 37degreesC and pH 7.4-7.45. Inter- and intra-assay coefficients of variations were 9 and 7%, respectively. The sensitivity and specificity for sperm MTT viability assay, E&N, and HOST were 97, 98, and 99%, and 100, 100, and 83% respectively. High significant correlations were obtained between sperm MTT viability assay, E&N, HOST and motility. Conclusions: Sperm MTT viability assay can be used as a diagnostic test for discrimination of viable sperms from sperm population.