E-Poster Presentation ESA-SRB-ANZBMS 2021

The effect of discrete wavelengths of visible light on the developing murine embryo (#500)

Carl CC Campugan 1 2 3 4 , Megan ML Lim 1 2 3 4 , Darren DC Chow 1 2 3 4 , Cheow Yuen (Tiffany) TC Tan 1 2 4 , Kylie KRD Dunning 1 2 3 4 , Erik ES Schartner 2 3 4 5 , Kishan KD Dholakia 2 3 6 7 8 , Jeremy JT Thompson 1 2 3 4
  1. Robinson Research Institute, Adelaide, South Australia, Australia
  2. The University of Adelaide, Adelaide, SA, Australia
  3. Institute for Photonics and Advanced Sensing, Adelaide, South Australia, Australia
  4. Australian Research Council Centre of Excellence for Nanoscale BioPhotonics, Adelaide, South Australia, Australia
  5. School of Physical Science, The University of Adelaide, Adelaide, South Australia, Australia
  6. School of Physics and Astronomy, University of St Andrews, St Andrews, North Haugh, Scotland
  7. School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
  8. Department of Physics, College of Science, Yonsei University, Seoul, South Korea

Non-invasive optical imaging has potential in determining developmental potential of the embryo. Such approaches use light at varying wavelengths. The impact of irradiating preimplantation embryos with discrete wavelengths of light has not been investigated appropriately. Light has several parameters that may affect embryos. These include wavelength, the average and peak power, exposure duration, and overall energy dose delivered to the embryo. Our study distinguishes itself from previous work by: (i) ensuring that light is applied uniformly across the embryo; (ii) having accurate calibration of the energy dose; and (iii) a knowledge of the spectral bandwidth of each light source. In this study we performed rigorous comparison between wavelengths by accounting for the above-mentioned factors.

We exposed embryos to blue (470nm), green (520nm), yellow (590nm), or red (620nm) light at varying developmental stages assessing development to blastocyst and, DNA damage, inner cell mass (ICM) and total cell numbers (TCN) in the blastocyst-stage embryo. Four experimental exposure groups were used (unexposed, or from the morula – blastocyst, 4-cell – blastocyst or 1-cell – blastocyst stages), thus, embryos were exposed once a day for 0, 2, 3 or 5 days of preimplantation development.

Compared to unexposed embryos, blastocyst rate was significantly lower in embryos exposed to yellow light from the 1-cell to blastocyst stage (P<0.05) and 4-cell to blastocyst stage (P<0.01). Significantly higher levels of DNA damage in the blastocyst occurred for most wavelengths and developmental stages exposed, compared to unexposed embryos (P<0.05). When compared to unexposed, TCN was significantly lower in red exposed embryos (P<0.05). The ICM was not affected by any wavelength.

Our results show that embryo development is impacted not only by wavelength, but also the frequency of exposure and developmental stage exposed, demonstrating that developmental rate alone may not indicate the full impact of light on the developing embryo.