The effect of propanediol on the morphology of fresh and frozen equine embryos.

This study evaluates the impact of propanediol on fresh and frozen equine embryos, finding that propanediol has a minimal toxic effect but is not effective as a cryoprotectant.

Study Design and Methodology

• The researchers conducted their study on seventeen horse embryos that were collected on the sixth day following spontaneous ovulation.
• These embryos were divided into three groups. The first group of six embryos was washed in PBS (Phosphate Buffered Saline), the second group of another six embryos were treated with 1.5 M 1-2 propanediol, and the remaining five embryos were frozen and thawed using 1.5 M propanediol as the cryoprotectant.

Treatment and Examination

• After the respective treatments, the embryos were incubated for six hours in a medium.
• The embryos were then fixed, serially sectioned, and examined under a microscope. The scientists conducted a count of the total numbers of interphase (non-dividing cells), mitotic (cell division phase), and pycnotic (a sign of cell death) nuclei.

Findings and Conclusion

• Significant differences were only measured in the average proportions of pycnotic cells. In the control group, the percentage of such cells was 9.2% (+/- 7.3%), compared to 52.8% (+/- 37.1%) in the frozen-thawed embryos, indicating a significant increase (P<0.05).
• There was also a significant difference when comparing the group treated with propanediol (10.8% +/- 4.6%) and the frozen-thawed embryos.
• These findings suggest that propanediol has a minimal toxic effect on equine embryos. However, it does not act well as a cryoprotectant, shown by the high percentage of cell death (pycnosis) in the embryos that were frozen and thawed using propanediol.