Influence of follicular fluid and gonadotropin supplementation on the expression of germ cell marker genes during in-vitro maturation of caprine (Capra hircus) oocytes

- The nuclear maturation rate was significantly higher in maturation media supplemented with follicular fluid and gonadotropins.
- The relative expression pattern of MATER gene was found to be significantly down regulated in maturation media supplemented with follicular fluid and gonadotropins.
- The expression profile of key oocyte marker genes are changes with culture conditions.

The present study aimed to investigate whether follicular fluid, gonadotropins (FSH, LH and estradiol-17β), and combination of both types of supplementation (follicular fluid + gonadotropins) in maturation medium influence the transcript abundance of germ cell marker genes (MATER, ZAR1, GDF9 and BMP15) in goat oocytes. Grade I and II oocytes were collected from the goat ovaries and matured further under in-vitro conditions using four different maturation regimens viz, group B containing basal media (TCM 199 + BSA + serum), group C (basal media + 10% follicular fluid), group D (basal media + FSH + LH + estradiol-17β) and group E (basal media + 10% follicular fluid + FSH + LH + estradiol-17β). Group A consisted of immature oocytes. Expression profile of MATER, ZAR1, GDF9, and BMP15 was analyzed in matured oocytes of different groups as well as immature oocytes using real-time PCR. The relative abundance of MATER gene in immature oocytes (group A) was found to be significantly higher (p < 0.05) compared to experimental groups. The relative expression of ZAR1 was found to be significant different (P < 0.05) between group D and E. The relative expression of GDF9 and BMP15 was significantly higher (P < 0.05) in group E as compared to other experimental groups. These results indicated that the expression of MATER and ZAR1 transcript were down regulated after maturation; however BMP15 and GDF9 transcripts were upregulated after maturation. For better in vitro embryo production (IVEP) out comes goat oocytes may be matured in vitro in TCM-199 supplemented with follicular fluid and gonadotropins.