Kinetics of occurrence of some features of apoptosis during the cryopreservation process of bovine spermatozoa

Abstract

The early features of apoptosis appear as ordered events during the cryopreservation/thawing process of bovine sperm cells. Bovine spermatozoa contain the machinery necessary to proceed to apoptosis involving especially the mitochondrial pathway.

Toxicity of glycerol for the stallion spermatozoa: Effects on membrane integrity and cytoskeleton, lipid peroxidation and mitochondrial membrane potential

“…Recent data in somatic cells indicates that osmotic stress may induce caspase 8 activation [47]. Activation of caspase 8 occur during human sperm cryopreservation [48], but not in bovine sperm cryopreservation [49]. In view of our results the toxicity to glycerol explain some of the damages induced by cryopreservation, the toxicity induced by glycerol may be enhanced when the cryoprotectant is concentrated in the frozen state [11].…”

Bovine spermatozoa react to in vitro heat stress by activating the mitogen-activated protein kinase 14 signalling pathway

“…Specifically, MAPK14 has been identified as a key signalling pathway for heat-induced testicular germ cell apoptosis by resulting in an imbalance in the mitochondrial Bax/ Bcl2 ratio (Jia et al 2009). Therefore, in the present study, we hypothesised that heat stress may activate the MAPK14 signalling pathway in spermatozoa and cause cell death by activating mitochondrial Bax, because Bcl2 is not detected in bovine spermatozoa (Martin et al 2007). To confirm our hypothesis we used an antibody against p-MAPK14 and observed heat stress-induced MAPK14 activation.…”

“…It was believed that mature spermatozoa do not possess effective mechanisms for protein synthesis or DNA degradation and that the apoptotic cascade does not commence in spermatozoa in the mature state. However, recent data support the notion that apoptosis, or at least apoptotic-like processes, can be induced in ejaculated spermatozoa by a variety of stimuli or stresses (Martin et al 2007;Ball 2008;Brum et al 2008). These stresses and stimuli (e.g.…”

“…However, it is not clear whether MAPK signalling pathways operate in ejaculated spermatozoa because they are transcriptionally inactive and their translational machinery is thought to be lost with the residual cytoplasm. However, compelling evidence suggests that features typically associated with apoptosis on the plasma membrane in somatic cells, including DNA fragmentation, low MMP, loss of plasma membrane integrity and PSE, are also present in the ejaculated human, boar, horse, bull, rat, hamster and mouse spermatozoa (Aziz et al 2007;Martin et al 2007;Brum et al 2008;Said et al 2008). In an in vivo study in rats, Jia et al (2009) showed that MAPK14 is the key signalling pathway involved in heat-induced testicular germ cell apoptosis, inducing Bcl2 phosphorylation, which leads to its inactivation and subsequent activation of the mitochondria-dependent death pathway, mainly as a result of an imbalance in the Bax : Bcl2 ratio.…”

Impact of caspase activation in human spermatozoa

“…Caspase activation following the cryopreservation and thawing process was also seen in animal germ cells, e.g., in bovine (Martin et al, 2004(Martin et al, , 2007 and equine spermatozoa (Brum et al, 2008;Ortega-Ferrusola et al, 2008). However, supplementation of cryopreservation media with caspase inhibitors does not improve the cryosurvival rates of sperm (Peter et al, 2005).…”