Sperm mitochondrial regulation in motility and fertility in horses

Abstract

The biological nature of age‐related declines in fertility in males of any species, including stallions, has been elusive. In horses, the economic costs to the breeding industry are frequently extensive. Mitochondrial function in ejaculated sperm, which is essential for sperm motility, is reflected by adenosine triphosphate production, mitochondrial oxidative efficiency and production of reactive oxygen species, and that this balance may become compromised in ageing stallions and during the process of cryopreservation. This presentation will focus on mitochondrial integrity and function as an avenue for understanding the pathophysiology of sperm when undergoing cryopreservation and male ageing. We discuss the importance of understanding the differences and similarities of sperm mitochondria to that of somatic cells regarding structure and mitochondrial biochemistry relating to sperm function. The roles of oxidative phosphorylation and glycolysis in sperm mitochondria are outlined as is the method of determining oxygen consumption and calcium homoeostasis in sperm mitochondria. Further, we outline the role of oxidative stress and reactive oxygen species.

Red-Light Irradiation of Horse Spermatozoa Increases Mitochondrial Activity and Motility through Changes in the Motile Sperm Subpopulation Structure

“…Recent studies have concurred that oxygen consumption is an alternative way to measure mitochondrial activity, which could be better than the use of markers of mitochondrial membrane potential, such as JC1 [ 53 , 54 ]. In addition to this, the rate of oxygen consumption also provides an indirect measure of ATP produced by oxidative phosphorylation in sperm [ 54 ].…”

“…Recent studies have concurred that oxygen consumption is an alternative way to measure mitochondrial activity, which could be better than the use of markers of mitochondrial membrane potential, such as JC1 [ 53 , 54 ]. In addition to this, the rate of oxygen consumption also provides an indirect measure of ATP produced by oxidative phosphorylation in sperm [ 54 ]. The results obtained in this study agree with this possibility, since they showed an increase in intracellular ATP levels and O 2 consumption rate (O 2 consumption rate normalized against the corresponding control) in samples irradiated for 4 min, compared with the non-irradiated control.…”

Red LED Light Acts on the Mitochondrial Electron Chain of Donkey Sperm and Its Effects Depend on the Time of Exposure to Light

“…Recent studies indicate that oxygen consumption represents an alternative measure of mitochondrial activity, which could be better than the use MMP markers, such as JC1 (Moscatelli et al, 2017;Meyers et al, 2019). Oxygen consumption rate would also provide an indirect measure of ATP produced by oxidative phosphorylation in mammalian sperm (Meyers et al, 2019). The results obtained in this study showed an increase in oxygen consumption on all irradiated samples (namely, light-stimulated for 1, 5, or 10 min) in the absence of Omy A or FCCP compared to the non-irradiated control.…”

Novel Low-Voltage Electro-Ejaculation Approach for Sperm Collection from Zoo Captive Lanyu Miniature Pigs (Sus barbatus sumatranus)

“…Movement of the sperm cells requires constant energy supplementation (e.g., ATP) provided by functional mitochondria. Defective or dysfunctional sperm mitochondria has been shown to associate with low fertility in many species, including humans, horses, and dogs [ 8 , 33 , 34 , 35 , 36 ]. We detected severe decline in sperm membrane potential after cryopreservation process, suggesting that the function of mitochondria was affected after cryopreservation.…”

“…Preservation of gametes requires collection of sperm cells and/or oocytes using optimized protocols to minimize potential damages on gametes [ 2 , 3 ]. However, due to species-specific and individual variations, the collection, preservation, and retrieval of gametes are always challenging for veterinarians [ 1 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Semen collection in animals can be achieved by either electro-ejaculation (EEJ) or by penile hand massage.…”