Comparison of cell proliferation index in equine and caprine embryos using a modified BrdU incorporation assay.

This study aimed to adapt a technique used for measuring cell proliferation and viability in multiple cell types and species to equine embryos. The researchers used the 5’bromo-2’deoxy-uridine (BrdU) labelling technique to compare DNA replication in both equine and caprine embryos. Results indicated a significantly higher rate of cell proliferation in equine embryos as compared to caprine embryos.

Research Methodology

• The research involved studying cell growth by labeling DNA with BrdU, a brominated DNA base analog. 17 equine embryos were collected on the 6.5th day after ovulation while 20 caprine embryos were collected on day 7 after the start of estrus.
• The equine embryos were treated for an hour at 39 degrees C in Phosphate-buffered saline (PBS) with a 1mM concentration of BrdU. This was followed by trypsin treatment to permeabilize the embryo coating and then rinsing in PBS with foetal calf serum.
• The embryos were then quickly fixed with 2.5% paraformaldehyde with 0.3M NaOH at room temperature for 15 minutes. This S-phase was detected by immunocytochemistry technique.
• The same procedure, excluding the trypsin treatment, was implemented for the caprine embryos. This variation was due to differences in the cellular structure and makeup of equine and caprine embryos.

Results

• In the process of DNA synthesis, a comparably higher cell proliferation rate was found in equine embryos (74+/-1) compared to that in caprine embryos (38+/-2).
• Their research confirms that the BrdU incorporation assay can be utilized effectively for equine embryos.
• The study’s findings suggest the potential for using cell proliferation as an additional means of measuring the viability of embryos, supplementing traditional viability tests.

Implications

• The study underlines that there is a more intensive cell proliferation activity in equine embryos compared to caprine embryos.
• Additionally, the research implies that the cellular cycle among equine embryos may be shorter due to the high rate of BrdU incorporation during the one-hour incubation period.
• The study suggests that the modification of the BrdU incorporation assay to equine embryos provides a valuable tool contributing to the field of animal embryology.