Effect of in vitro culture conditions on the quality of rabbit embryos

Abstract

The aim of our study was to examine effect of in vitro culture on preimplantation rabbit embryo quality (total cell number, number of blastomeres in the inner cell mass (ICM) area, apoptotic index and embryo diameter). Rabbit embryos of the New Zeland White breed were flushed from the oviducts 19 – 20 hours post coitum and cultured up to the blastocyst stage (the experimental group). As a control group, the embryos developed in vivo were used, which were flushed from the uterus at the expanded blastocyst stage 94 hours post coitum. Embryos were stained by propidium iodide and Hoechst 33342 to detect total cell number and number of cells in the ICM area. For detection of apoptotic cells, TUNEL-reaction was used. Significantly higher number of blastomeres in ICM (p<0.05) was found out in the control group (44.18±2.50) when compared to the experimental group (36.22±2.45). However, total cell number of embryos was not significantly different between these two groups (155.12±15.00 vs. 127.23±14.50), respectively. Significant difference between control and experimental groups in the number of apoptotic cells (0.35 vs. 1.25) and embryo diameter (133.95±8.95 vs. 123.40±7.25 μm) was not proved too. Our results demonstrate slightly worse quality of rabbit embryos cultured in vitro, compared to embryos developed in vivo what is reflected in the number of cells in embryoblast.