The Influence of Light on Apoptosis in Preimplantation Mouse Embryos In Vitro

Background: In vitro culture of mammalian embryos can slow or stop growth completely. This may be due to the medium used, pH, temperature, or light. There is considerable concern about the harmful effect of light in the laboratory environment. Cell number and apoptosis are useful parameters that indicate embryonic development and health. In this study, we assessed these two factors in the blastocyst. Materials and methods: A total of 128 embryos were extracted from NMRI mice at the 2-cell stage and were divided into 4 groups. The embryos were exposed to light for 0, 5, 15, and 30 min, and then cultured for 96 h. The degree of embryonic development were recorded every 24 h. Furthermore, several morphologically normal blastocysts were evaluated using the TUNEL assay. Results: There was no significant difference in developmental stages between the experimental and control groups. An evaluation of the percentage of blastomeres and apoptotic cells revealed significant differences among the four groups. The maximum number of apoptotic blastomeres was observed in the group exposed to light for 30 minutes. Conclusion: Up to thirty minutes of white fluorescent light can induce apoptosis in blastomeres, but it does not prevent embryo development.