Improvement in bovine embryo production in vitro by treatment with green tea polyphenols during in vitro maturation of oocytes

• Published in: Animal reproduction science Vol. 100; no. 1; pp. 22 - 31
• Main Authors: Wang, Zheng-guang, Yu, Song-dong, Xu, Zi-rong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.07.2007
• Subjects: animal reproduction; Animals; antioxidant activity; antioxidants; Bovine oocytes; Cattle; cows; Culture Techniques; embryo (animal); Embryo Transfer - veterinary; Embryo, Mammalian - drug effects; Embryo, Mammalian - physiology; embryogenesis; Female; Fertilization in Vitro - drug effects; Fertilization in Vitro - veterinary; Flavonoids - chemistry; Flavonoids - pharmacology; glutathione; green tea; Green tea polyphenols; in vitro culture; In vitro fertilization; In vitro maturation; maturity stage; new methods; oocytes; Oocytes - drug effects; Oocytes - growth & development; Phenols - chemistry; Phenols - pharmacology; Polyphenols; reactive oxygen species; Tea - chemistry; Green tea polyphenols; In vitro fertilization; Bovine oocytes; In vitro maturation
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2006.06.014

The present study examined the effect of green tea polyphenols (GTP) during in vitro maturation (IVM) of bovine oocytes on in vitro fertilization (IVF) parameters, intracellular glutathione (GSH) concentration and subsequent embryo development. Cumulus-oocyte complexes were aspirated from the ovaries derived from slaughterhouse and cultured in modified synthetic oviduct fluid (m-SOF) supplemented with 0–25 μM GTP for 24 h. After IVM, cumulus-free oocytes were coincubated with frozen-thawed spermatozoa for 15–18 h. Putative embryos were transferred to m-SOF and cultured for 8 days (Experiment 1). In comparison with the absence of GTP, treatment with GTP at a concentration of 15 μM showed a significant increase in the proportion of pronuclear (PN) formation after sperm penetration (65% versus 80%, P < 0.05). No significant differences in the rates of sperm penetration and polyspermic fertilization were found among treatments. The cleavage rate at 48 h of in vitro insemination showed no difference in oocytes matured with or without GTP. However, compared to no addition (23.5%), the presence of 15 and 20 μM GTP during IVM significantly ( P < 0.05) increased the proportion of blastocysts (38.1% and 36.4%) on day 9 of in vitro insemination. A further increase from 20 to 25 μM GTP reduced ( P < 0.05) the proportion of blastocysts. In Experiment 2, after IVM, oocytes were fixed to analyze the GSH concentration. Compared to no addition, a higher ( P < 0.05) level of GSH was found in oocytes matured with 15 μM GTP and compared with 15 μM GTP, GSH was low ( P < 0.05) at 20 and 25 μM GTP. The results suggest that at certain concentrations of GTP (15 μM) in IVM medium has beneficial effects on subsequent embryo development, and is correlated with intracellular GSH level in bovine oocytes.