In vitro Maturation of Buffalo Oocytes and Expression of Selected Biomarker Candidate Genes

Background: Number of genes expressed during in vitro maturation (IVM) of which selected genes can be used as the potential biomarkers of oocyte competence. Hence, this study was planned to evaluate selected gene expression of GDF9, HAS2, SPRY, ARHGAP22, COL18A1 and GPC4 in IVM and immature cumulus oocyte complexes (COCs). Methods: The COCs were recovered from slaughter origin ovaries of buffaloes. Of which first three grade COCs were randomly allotted in immature (IMT; n=217) and IVM group (n=272). IVM of COCs was performed under drops of BO-maturation media in CO2 incubator at 39.0°C for 24 hours. The expression of genes was evaluated using qPCR and the relative expression of each gene was calculated using the ΔΔCt method with efficiency correction. The logarithmic transformation of fold change of each candidate genes in the IVM group was computed against the IMT group using the Ct values. Result: The expression obtained for IVM group of earlier reported up-regulated genes (GDF9, HAS2, SPRY1) was higher (upto 10xfold) compared to the IMT group. Relatively lower expression was observed for the rest of the three candidate genes (ARHGAP22, COL18A1, GPC4) in the bovine transcripts of oocyte which were earlier also reported as down regulated.