Effect of vitrification and beta-mercaptoethanol on reactive oxygen species activity and in vitro development of oocytes vitrified before or after in vitro fertilization  Mukesh Kumar Gupta, Ph.D., Sang Jun Uhm, Ph.D., Hoon Taek Lee, Ph.D.  Fertility and Sterility  Volume 93, Issue 8, Pages 2602-2607 (May 2010) DOI: 10.1016/j.fertnstert.2010.01.043 Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions

Figure 1 Survival rate of porcine oocytes vitrified at metaphase II stage (open bars) or shortly after in vitro fertilization (solid bars). (A) Oocytes vitrified and cultured in the absence of beta-mercaptoethanol. (B) Oocytes vitrified and cultured in the presence of beta-mercaptoethanol. Values within bars indicate the number of oocytes (n). Bars with different letters (a, b, and c) are statistically different (P<.05). TC = toxicity control. Fertility and Sterility 2010 93, 2602-2607DOI: (10.1016/j.fertnstert.2010.01.043) Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions

Figure 2 Reactive oxygen species activity in porcine oocytes cultured in the presence (A2, B2, and C2) or absence (A1, B1, and C1) of beta-mercaptoethanol. (A) Control oocytes. (B) Cryoprotectant-treated nonvitrified oocytes (toxicity control). (C) Vitrified-warmed oocytes. Numeric values on figures indicate the average fluorescence intensity (mean ± SEM). Magnification ×100. Values with different superscripts (a, b, c, and d) are statistically different (P<.05). Values in parentheses indicate the number of oocytes analyzed for ROS activity in each group. Fertility and Sterility 2010 93, 2602-2607DOI: (10.1016/j.fertnstert.2010.01.043) Copyright © 2010 American Society for Reproductive Medicine Terms and Conditions