The sperm penetration assay is often used as a prognostic test to assess male fertility in vitro, but a consensus has not been achieved on a specific protocol for the assay yet. Moreover, controversy surrounds the assay because of its frequent lack of...
The sperm penetration assay is often used as a prognostic test to assess male fertility in vitro, but a consensus has not been achieved on a specific protocol for the assay yet. Moreover, controversy surrounds the assay because of its frequent lack of correlation with male fertilizing capacity, which may be due to low percentage of capacitated sperm resulting from the assay. With the use of low-temperature capacitation(4℃)in TEST-yolk buffer to increase the proportion of acrosome reacted sperm, the ability of human spermatozoa to penetrate zona-free hamster ova was examined, and sources of variability in the assay were investigated. Results obtained from the study demonstrated that the penetration index defined as the number of sperm penetrations per total ova in seminated were increased by an average of 1.7-fold when spermatozoa was capacitated for 42 hours, as compared with 18 hours. Penetration index was also increased by an average of 2.4-fold in the presence of 0.3% human serum albumin compared with 3.5% human serum albumin in Biggers, Whitten, and Whittingham`s(BWW) medium used for sperm-egg incubation. Increasing the albumin concentration in BWW medium used for recovery of motile sperm from 0.3% to 1.0% or 3.5% did not enhance the penetration index. If the variables studied here are consistently controlled, then the assay could be optimized further for sensitivity and negative predicatability, and the assay results might reflect sperm performance more accurately than the traditional assay.