Effect of Linolenic acid during in vitro maturation of ovine oocytes: embryonic developmental potential and mRNA abundances of genes involved in apoptosis

To study the effect of alpha-linolenic acid (ALA) on meiotic maturation, mRNA abundance of apoptosis-related (Bax and Bcl-2) molecules, and blastocyst formation in ovine oocytes.Purpose To study the effect of α-linolenic acid (ALA) on meiotic maturation, mRNAabundance of apoptosis-related (Bax and Bcl-2) molecules, and blastocyst formation inovine oocytes.Methods A preliminary experiment was conducted to analyze the concentration of ALAin "small" (≤2 mm) and "large" (≥6 mm) follicles using gas chromatography/massspectrometry analysis. The concentration of ALA in small and large follicles wasdetermined to be in a range of 75.4 to 125.7 μM, respectively. In vitro maturation (IVM)of oocyte was then performed in presence of 0 (control), 10 (ALA-10), 50 (ALA-50),100 (ALA-100), and 200 (ALA-200) μM of ALA. Meiotic maturation and mRNAabundance of Bax, and Bcl-2 genes was evaluated after 24 h of IVM. The embryoniccleavage and blastocyst formation following parthenogenetic activation were alsodetermined for each group.Results The highest concentration of ALA (ALA-200) decreased the oocyte maturationrate compared with the control group. Analysis of apoptosis-related genes in oocytesafter IVM revealed lesser transcript abundances for Bax gene, and higher transcriptabundances for Bcl-2 gene in ALA-treated oocytes as compared with the controloocytes. In term of cleavage rate (considered as 2-cell progression), we did notobserve any differences among the groups. However, ALA-100 group promoted moreblastocyst formation as compared with the control group.Conclusion Our results suggested that ALA treatment during IVM had a beneficial effect on developmental competence of ovine oocytes by increasing the blastocystformation and this might be due to the altered abundance of apoptosis-regulatorygenes.