Effect of mitochondrial uncoupling and glycolysis inhibition on ram sperm functionality

Abstract

Studies have demonstrated the importance of mitochondria to sperm functionality, as the main source of ATP for cellular homoeostasis and motility. However, the role of mitochondria on sperm metabolism is still controversial. Studies indicate that, for some species, glycolysis may be the main mechanism for sperm energy production. For ram sperm, such pathway is not clear. Thus, we evaluated ram sperm in response to mitochondrial uncoupling and glycolysis inhibition aiming to assess the importance of each pathway for sperm functionality. Statistical analysis was performed by the SAS System for Windows, using the General Linear Model Procedure. Data were tested for residue normality and variance homogeneity. A p < .05 was considered significant. Groups treated with the mitochondrial uncoupler Carbonyl cyanide 3 chlorophenylhydrazone (CCCP) showed a decrease in the percentage of cells with low mitochondrial activity and high mitochondrial membrane potential. We also observed that the highest CCCP concentration promotes a decrease in sperm susceptibility to lipid peroxidation. Regardless the lack of effect of CCCP on total motility, this substance induced significant alterations on sperm kinetics. Besides the interference of CCCP on spermatic movement patterns, it was also possible to observe such an effect in samples treated with the inhibitor of glycolysis (2-deoxy-d-glucose, DOG). Furthermore, treatment with DOG also led to a dose-dependent increase in sperm susceptibility to lipid peroxidation. Based on our results, we suggest that the glycolysis appears to be as important as oxidative phosphorylation for ovine sperm kinetics as this mechanism is capable of maintaining full motility when most of the cells have a low mitochondrial membrane potential. Furthermore, we found that changes in the glycolytic pathway trough glycolysis inhibition are likely involved in mitochondrial dysfunction and sperm oxidative unbalance.

Carnosine treatment during human semen processing by discontinuous density gradient

“…In addition, carnosine potentially inhibits the release of cytochrome c that leads to mitochondrial protection against damage (Baek et al, ). Carnosine is also a possible glycolysis inhibitor, since it could lead to mitochondrial dysfunction and oxidative imbalance (Losano et al, ). These data may have interfered in the motility results presented when the seminal sample was supplemented with the antioxidant.…”

The Stimulated Glycolytic Pathway Is Able to Maintain ATP Levels and Kinetic Patterns of Bovine Epididymal Sperm Subjected to Mitochondrial Uncoupling

“…Complementary in ram, Losano et al [9] demonstrated that mitochondrial depolarization did not affect total motility; however, sperm kinetic patterns were altered. On the other hand, they found that glycolytic pathway inhibition impaired total motility and sperm movement patterns.…”

Spermatic mitochondria: role in oxidative homeostasis, sperm function and possible tools for their assessment

“…;Bilodeau et al, 2001;Fernández-Santos et al, 2007; We verified that mitochondrial uncoupling [carbonyl cyanide 3 chlorophenylhydrazone (CCCP); 20, 40 and 80 µM] impairs ovine sperm kinetic patterns such as progressive motility (A), straight-line velocity (VSL; B) and linearity (LIN; C), indicating an essential role of mitochondria to sperm quality movement related to progressivity(Losano et al, 2017b). a,b Different letters on the bars indicate significant differences between treatments (P < 0.05).…”