Kruger strict morphology and post-thaw progressive motility in cryopreserved human spermatozoa

Abstract

The purpose of this prospective study was to evaluate Kruger strict morphology and conventional semen analysis in predicting cryosurvival and the progressive motility recovery rate of frozen spermatozoa. Our study included 56 semen samples with >10 million spermatozoa per ejaculate. The main outcome measures were conventional semen analysis, strict morphology analysis by the Kruger method, cryosurvival rate and post-thaw sperm motility. A significant reduction in sperm motility after cryopreservation was demonstrated. The freeze-thawing process caused a 66% reduction in rapid progressive motile spermatozoa, a 45% reduction in slow progressive motile spermatozoa and a 2% reduction in nonprogressive motile spermatozoa. The cryosurvival and progressive motility recovery rates were not correlated with parameters of conventional semen analysis, such as sperm concentration, motility, WHO morphology and total motile count, but the progressive motility recovery rate was significantly correlated with the percentage of spermatozoa exhibiting Kruger normal morphology (P = 0.028). The recovery rate of rapidly progressive motility was profoundly decreased compared with slow progressive motility following the frozen-thaw procedure of semen. Kruger strict morphology assessment was a better predictor of the progressive motility recovery rate following the freezing-thaw procedure than parameters of conventional semen analysis.

Effect of pre-freezing conditions on the progressive motility recovery rate of human frozen spermatozoa

“…Lee et al . () presented that the progressive motility recovery rates were not correlated with semen parameters, such as sperm concentration, progressive motility and WHO morphology, and that it was significantly correlated with the percentage of normal morphology spermatozoa for the Kruger standard. Based on our statistical study of a large sample size, however, the correlation between the three parameters and the progressive motility recovery rate existed.…”

“…Despite this, the relationship between pre‐frozen conditions like semen characteristics, duration of abstinence and seasons are not clear. Some studies have aimed to answer these questions (Dong et al ., ; Dorado et al ., ; Lee et al ., ) but no conclusions have been established as they either studied these parameters in animal models or used a small number of human samples. As the understanding of the relationship would strongly improve the ability of sperm banks to predict the rate of recovery post‐freezing and the instruction of sperm donating process, statistical study of the correlation of pre‐frozen conditions and cryopreservation recovery rate in larger human population is in needed.…”

Semen cryopreservation for men banking for oligospermia, cancers, and other pathologies: prediction of post-thaw outcome using basal semen quality

“…In addition, whether the expected decrease in sperm functions is related, or can be predicted, on the basis of semen quality on the day of cryopreservation has also been poorly documented. One study (15) reported that Kruger strict morphology assessment, among the conventional semen parameters, was the best predictor of progressive motility recovery after thawing in a small number of normozoospermic samples. Other studies (16,17) evaluating the relationship between prefreezing and post-thawing semen characteristics demonstrated that higher concentration and prefreeze motility and fewer abstinence days are associated with an increased recovery rate in donors for a sperm bank.…”

Multivariate model for predicting semen cryopreservation outcomes in a human sperm bank

“…In the study by Lee et al . the postthaw recovery of progressive motility of human spermatozoa showed no correlation with prefreezing semen parameters, such as sperm concentration, progressive motility or WHO-based criteria morphology, but it was significantly correlated with the percentage of spermatozoa with normal morphology assessed by strict application of Kruger critera 5. Others found that the recovery of progressive motility of frozen spermatozoa was significantly and positively affected by sperm concentration, progressive motility and the percentage of normal morphology 6816.…”

“…Lee et al . reported that, compared with conventional semen analysis, Kruger strict morphology criteria were better predictors of the postthaw progressive motility recovery 5. Others found that higher concentration and prefreeze motility and fewer days of abstinence before producing a semen sample were associated with an increased sperm recovery rate through evaluating the relationship between prefreezing and postthawing semen characteristics 678.…”