Impact of gonadotropin supplementation on the expression of germ cell marker genes (MATER, ZAR1, GDF9, and BMP15) during in vitro maturation of buffalo (Bubalus bubalis) oocyte

The present study was designed to investigate whether gonadotropins [follicle-stimulating hormone (FSH) and luteinizing hormone (LH)] and buffalo follicular fluid (bFF) supplementation in maturation medium influences the transcript abundance of germ cell marker genes [maternal antigen that embryos require (MATER), Zygote arrest 1 (ZAR1), growth differentiation factor 9 (GDF9), and bone morphogenetic protein 15 (BMP15)] mRNA in buffalo (Bubalus bubalis) oocytes. Buffalo ovaries were collected from local abattoir, oocytes were aspirated from antral follicles (5-8 mm) and matured in vitro using two different maturation regimens, viz, group A: gonadotropin (FSH and LH) and group B: non-gonadotropin-supplemented maturation medium containing 20% buffalo follicular fluid (bFF). mRNA was isolated from immature (330) and in vitro matured oocytes from both the groups (A, 320; B, 340), and reverse transcribed using Moloney murine leukemia virus reverse transcriptase. Expression levels of MATER, ZAR1, GDF9, and BMP15 mRNA transcripts were analyzed in oocytes of both maturation groups as well as immature oocytes using real-time PCR. QPCR results showed that GDF9 and BMP15 transcripts were significantly (p < 0.05) influenced with gonadotropins and bFF supplementation during in vitro maturation of buffalo oocyte; however, MATER and ZAR1 transcripts were not influenced with gonadotropins and bFF supplementation in vitro. These results indicated that the expression levels of MATER, ZAR1, GDF9, and BMP15 mRNA were varied differentially during in vitro maturation of buffalo oocyte and were found to be gonadotropins (FSH and LH) or bFF dependent for GDF9 and BMP15.