339 EFFECTS OF 17-β ESTRADIOL AND CYSTEAMINE ON IN VITRO MATURATION OF BEEF CATTLE OOCYTESL. Guo A , B. Tang A , X. Ma A , F. Gao A , J. B. Zhang A and Z. Y. Li A
Jilin University, Changchun, Jilin, China
Reproduction, Fertility and Development 22(1) 326-326 http://dx.doi.org/10.1071/RDv22n1Ab339
Published: 8 December 2009
IVM is a critical step in in vitro bovine embryo production. Some materials supplemented in the IVM medium could improve the maturation rate. It was reported that 17-β estradiol (E2) stimulated the FSH-induced follicular growth and expression of the LH receptor in mural granulosa cells, and cysteamine could enhance glutathione synthesis, protect cells against harmful effects caused by oxidative injuries. In order to optimize IVM system of beef cattle oocytes, effects of different supplements (E2 and cysteamine), and dose of supplements on IVM of beef cattle oocytes were investi- gated in this study. The COCs were collected and cultured in the basic IVM media (TCM-199 + 10% FCS + 10 μg mL-1 FSH + 30 μg mL-1 LH) supplemented with hormonesof 0 μg mL-1 (control), 1 μg mL-1, 2 μg mL-1, and 4 μg mL-1 E2, respectively. Statistical analyzes were performed using SPSS (version 9.0) one-way ANOVA. Oocyte maturation rates (mean ± SEM) of four supplement groups were 60.52 ± 1.4%, 74.91 ± 0.25%, 77.25 ± 2.08%, and 62.20 ± 1.87%, respectively. No statistical differences were observed (P > 0.05) between 1 μg mL-1 and 2 μg mL-1 E2 groups; a similar trend was seen between 0 μg mL-1 and 4 μg mL-1 E2 groups. However, oocyte maturation rates (74.91-77.25%) of groups of 1 μg mL-1 and 2 μg mL-1 E2 were significantly higher (P < 0.05) than those (60.52-62.20%) of the other two groups. When basic IVM medium was sup- plemented with 0 μg mL-1 (control), 50 μg mL-1, and 100 μg mL-1 cysteamine, oocyte maturation rates were 75.25 ± 0.25%, 80.56 ± 0.57%, and 76.83 ± 1.82%, respectively. No significant difference (P > 0.05) was observed among them. However, there was approximately five percent higher maturation rate in the supplement group with 50 μg mL-1 cysteamine than those of groups supplemented with 0 μg mL-1 and 100 μg mL-1 cysteamine. Our results indicated: i) the appropriate supplement of E2 (1 μg mL-1 to 2 μg mL-1) could improve in vitro maturation of beef cattle oocytes. Also, the excessive supplement of E2 (>4 μg mL-1) could inhibit the maturation; ii) appropriate supplement of cysteamine (50 μg mL-1) was benefit to the IVM of beef cattle oocytes.
This work was supported by the grant from national support plan, China, No. 2007BAD55B03; Corresponding author: Z.Y. Li.