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Light Irradiation of Mouse Spermatozoa: Stimulation of In Vitro Fertilization and Calcium Signals
Author(s) -
Cohen Natalie,
Lubart Rachel,
Rubinstein Sara,
Breitbart Haim
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb09700.x
Subject(s) - catalase , superoxide dismutase , reactive oxygen species , stimulation , calcium , chemistry , irradiation , biophysics , biochemistry , superoxide , biology , endocrinology , oxidative stress , enzyme , physics , organic chemistry , nuclear physics
Irradiation of mouse spermatozoa by 630 nm He‐Ne laser was found to enhance the intracellular calcium levels and fertilizing potential of these cells. The effect of light on calcium transport and on fertilization rate was abrogated in the absence of Ca 2+ during the irradiation time, indicating that the effect of light is Ca 2+ dependent. The stimulatory effect of light on Ca 2+ uptake was abolished in the presence of a voltage‐dependent Ca 2+ ‐channel inhibitor nifedipine, indicating the involvement of a plasma membrane voltage‐dependent Ca 2+ channel. Furthermore, the stimulatory effect of light was completely inhibited by the mitochondrial uncoupler FCCP, indicating that laser irradiation might affect the mitochondrial Ca 2+ transport mechanisms. A causal association between laser irradiation, reactive oxygen species (ROS) generation and sperm function was indicated by studies with ROS scavengers, superoxide dismutase (SOD) and catalase, and exogenous hydrogen peroxide. The SOD treatment, which enhanced H 2 O 2 production, resulted in increased Ca 2+ uptake and enhanced fertilization rate. On the other hand, catalase, which decomposes H 2 O 2 , impaired the light‐induced stimulation in Ca 2+ uptake and the fertilization rate. Taken together, the data suggest that H 2 O 2 might be involved in the irradiation effects, and indeed laser irradiation enhances the production of H 2 O 2 , by spermatozoa. These results indicate that the effect of 630 nm He‐Ne laser irradiation is mediated through the generation of H 2 O 2 by the spermatozoa and that this effect plays a significant role in the augmentation of the sperm cells' capability to fertilize metaphase H‐arrested eggs in vitro.