# Influence of BMI, Cigarette Smoking and Cryopreservation on Tyrosine Phosphorylation during Sperm Capacitation

## TL;DR

This study explores how BMI, smoking, and sperm freezing affect tyrosine phosphorylation during sperm capacitation, a key process for fertility.

## Contribution

The study reveals new insights into how lifestyle factors and cryopreservation influence tyrosine phosphorylation dynamics in human sperm.

## Key findings

- Elevated BMI and smoking intensity correlate with higher basal tyrosine phosphorylation levels in sperm.
- Cryopreservation increases global tyrosine phosphorylation levels after capacitation but not immediately after thawing.
- Phosphorylation patterns in fresh and frozen–thawed sperm are similar, suggesting consistent responses to capacitation stimuli.

## Abstract

Capacitation involves tyrosine phosphorylation (TP) as a key marker. Lifestyle-related factors, such as obesity and smoking, are recognized for their adverse effects on semen quality and male fertility, yet the underlying mechanisms, including their potential impact on TP, remain unclear. Moreover, the effect of sperm cryopreservation on TP at the human sperm population level is unexplored. Flow cytometry analysis of global TP was performed on pre-capacitated, post-capacitated and 1- and 3-hours’ incubated fresh and frozen–thawed samples from sperm donors (n = 40). Neither being overweight nor smoking (or both) significantly affected the percentage of sperm showing TP. However, elevated BMI and smoking intensity correlated with heightened basal TP levels (r = 0.226, p = 0.003) and heightened increase in TP after 3 h of incubation (r = 0.185, p = 0.017), respectively. Cryopreservation resulted in increased global TP levels after capacitation but not immediately after thawing. Nonetheless, most donors’ thawed samples showed increased TP levels before and after capacitation as well as after incubation. Additionally, phosphorylation patterns in fresh and frozen–thawed samples were similar, indicating consistent sample response to capacitation stimuli despite differences in TP levels. Overall, this study sheds light on the potential impacts of lifestyle factors and cryopreservation on the dynamics of global TP levels during capacitation.