The Effects of Red Light on Mammalian Sperm Rely upon the Color of the Straw and the Medium Used

Swimming trapper decreases the proportion of chromosomally unbalanced spermatozoa in human Robertsonian translocation carriers

BACKGROUND

Carriers of reciprocal translocations often have more unbalanced spermatozoa and higher DNA fragmentation rates, elevating reproductive risk. The simple swim-up method (SSUM) can decrease the amount of spermatozoa with abnormal chromatin structure and fragmented DNA, however, it has limited efficacy in eliminating chromosomally unbalanced sperm.

METHODS

The spermatozoa of eight Robertsonian translocation (Rob) carriers were split into three groups: original raw semen group (control group); SSUM and swimming trapper method group (STM) processed semen samples. After different semen preparation procedures, semen qualities, sperm chromosomal aneuploidy, and sperm fragmented DNA were evaluated.

RESULTS

Although spermatozoa with higher motility was obtained by both SSUM and STM, the population of faster forward moving sperm was greater with STM as compared to SSUM. While the rates of DNA fragmentation were statistically much lower in both groups than ejaculated semen sample, our data showed better effect on the decrease of DNA fragmentation index (DFI) after selection by STM for patients who have high DFI (>20%) in neat semen. For all patients, significant decrease in the frequency of chromosomally unbalanced spermatozoa was observed after selection using STM. Although similar trends can be seen in the SSUM group, a significant difference was identified in one patient only.

CONCLUSIONS

Use of swimming trapper (STM) is superior for enriching high-motile and genetically competent sperm in comparison with SSUM.

The effects of red LED light on pig sperm function rely upon mitochondrial electron chain activity rather than on a PKC-mediated mechanism

While irradiation with red LED light has been reported to modulate sperm function in different mammalian species, the mechanisms underlying their response are poorly understood. This work sought to provide new insights into whether this effect relies on a direct action upon mitochondrial electron chain and/or on PKC-linked mechanisms such as those related to opsins. For this purpose, pig semen was light-stimulated for 1, 5 or 10 min in the presence/absence of antimycin A, an inhibitor of the mitochondrial electron chain, or PKC 20–28^® (PKCi), a PKC inhibitor. Antimycin A completely blocked the effects of light at all the performed irradiation patterns. This effect was linked to a complete immobility of sperm, which was accompanied with a significant (p < 0.05) drop in several markers of mitochondrial activity, such as JC-1 staining and O₂ consumption rate. Antimycin A, however, did not affect intracellular ATP levels, intramitochondrial calcium, total ROS, superoxides or cytochrome C oxidase (CCO) activity. In the case of PKCi, it did also counteract the effects of light on motility, O₂ consumption rate and CCO activity, but not to the same extent than that observed for antimycin A. Finally, the effects observed when sperm were co-incubated with antimycin A and PKCi were similar to those observed with antimycin A alone. In conclusion, red LED light acts on sperm function via a direct effect on mitochondrial electron chain. Additionally, light-activated PKC pathways have a supplementary effect to that observed in the electron chain, thereby modulating sperm parameters such as motility and CCO activity.

Sperm kinetics of Egyptian buffalo bulls (Bubalus bubalis) affected by the red laser postfreezing

OBJECTIVE

To improve the fertilizing ability of frozen buffalo semen using the more beneficial, accurate, and cheap technique of laser irradiation at specific wavelengths and exposure times.

MATERIALS AND METHODS

The red laser source (625 nm) was used in this study with 5 watts output power and for the irradiation of the semen samples for 5 min; the laser focus spot area was 1 cm².Thirty straws belonging to five buffalo bulls were used in this study.

RESULTS

The results show that total motility (%) and progressive motility (%) increased insignificantly after 5 min of exposure (73.8 ± 1.4 and 60.4 ± 1.1, respectively) compared to the control sample (70.9 ± 0.9 and 57.5 ± 1.7, respectively). All velocity parameters (velocity average path,velocity curved line, and velocity straight line µm/sec) recorded a significant (p < 0.05) increase in samples measured 5 min after exposure (52.3 ± 1.3, 83.5 ± 2.0, and 43.5 ± 1.2, respectively) compared to the untreated ones (47.1 ± 2.0, 76.3 ± 3.1, and 38.6 ± 1.9, respectively).

CONCLUSION

The application of the red laser light on buffalo semen postthawing resulted in a positive correlation with almost every motility parameter; it may be recommended to apply this technique pre-in vitro fertilization for embryo production of buffalo species.

Male Infertility and Oxidative Stress: A Focus on the Underlying Mechanisms

Reactive oxygen species (ROS) play a critical role in defining the functional competence of human spermatozoa. When generated in moderate amounts, ROS promote sperm capacitation by facilitating cholesterol efflux from the plasma membrane, enhancing cAMP generation, inducing cytoplasmic alkalinization, increasing intracellular calcium levels, and stimulating the protein phosphorylation events that drive the attainment of a capacitated state. However, when ROS generation is excessive and/or the antioxidant defences of the reproductive system are compromised, a state of oxidative stress may be induced that disrupts the fertilizing capacity of the spermatozoa and the structural integrity of their DNA. This article focusses on the sources of ROS within this system and examines the circumstances under which the adequacy of antioxidant protection might become a limiting factor. Seminal leukocyte contamination can contribute to oxidative stress in the ejaculate while, in the germ line, the dysregulation of electron transport in the sperm mitochondria, elevated NADPH oxidase activity, or the excessive stimulation of amino acid oxidase action are all potential contributors to oxidative stress. A knowledge of the mechanisms responsible for creating such stress within the human ejaculate is essential in order to develop better antioxidant strategies that avoid the unintentional creation of its reductive counterpart.