Temporal analysis of cryopreservation effects on human sperm phospholipase C zeta expression profile: Laboratory preliminary findings

Abstract

Objectives: The objectives of this study were to compare the sperm parameters and sperm phospholipase C zeta (PLC ζ) expression profile before and after vitrification. Materials and Methods: Pre-vitrification and post-vitrification analysis of semen samples of 14 infertile men was carried out for sperm parameters such as motility, vitality, and morphology by standard semen analysis procedures, whereas the proportion of sperms exhibiting PLC ζ and its localization pattern was assessed by indirect immunofluorescence. The temporal analysis was done thrice: over 1 week, 1 month, and 3 months of cryostorage. Statistical Analysis: Statistical analyses were performed using GraphPad Prism version 8.0.1 (San Diego, California, USA). Data were expressed as mean ± standard deviation. Parametric or non-parametric tests were employed for comparisons according to the normality of data distribution and the available data set. P value of 0.05 was considered statistically significant. Results: Vitrification was found to be associated with a decrease in the percentage of sperm motility (P ≤ 0.0001), vitality (P ≤ 0.0001), spermatozoa exhibiting normal morphology (P > 0.05), and PLC ζ protein (P > 0.05), however, the latter two, only, insignificantly. There was increased dominance in the post-acrosomal localization of PLC ζ after vitrification (P ≤ 0.001). Conclusions: The post-acrosomal localization of PLC ζ has been reported to have the highest positive correlation with oocyte fertilization and the present study showed the predominant pattern of the same. The implications for quality maintenance for long storage periods can be suggested as better sperm quality was observed at 3 months of storage during this study. This raises the hypothesis that the vitrification method of sperm cryopreservation may be the method of choice for routine clinical use in the assisted reproductive technology settings.