Chronological characterization of sperm morpho-functional damage and recovery after testicular heat stress in Nellore bulls.

Heat stress (HS) affects spermatogenesis and sperm maturation, decreasing sperm quality. Yet sperm morpho-functional changes caused by HS in Nellore bulls are not fully elucidated. This study aimed to show the chronological effects on sperm quality of HS during spermatogenesis and sperm maturation until recovery of the seminiferous epithelium in Nellore bulls.

Changes in miRNA levels of sperm and small extracellular vesicles of seminal plasma are associated with transient scrotal heat stress in bulls.

Scrotal heat stress affects spermatogenesis and impairs male fertility by increasing sperm morphological abnormalities, oxidative stress and DNA fragmentation. While sperm morpho-functional changes triggered by scrotal heat stress are well described, sperm molecular alterations remain unknown. Recently, spermatozoa were described as accumulating miRNAs during the last steps of spermatogenesis and through epididymis transit, mainly by communication with small extracellular vesicles (sEVs).

Heat stress effects on bovine sperm cells: a chronological approach to early findings.

Testicular heat stress affects sperm quality and fertility. However, the chronology of these effects is not yet fully understood. This study aimed to establish the early sequential effects of heat stress in bull sperm quality.