Cystinosis

Reports outline Life Sciences study findings from University of Agriculture

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"The control medium was a modified TCM199 containing 0.05% (w/v) polyvinyl alcohol (PVA). Cys and/or cystine were added to the control medium. The control group and immature oocytes (presumptive germinal vesicle oocytes; GV) were prepared for GSH assay. In Experiment 3, the efficacy of epidermal growth factor (EGF) addition to a modified porcine zygote medium (mPZM) for in vitro culture (IVC) medium was investigated on embryonic development and the mean cell number of blastocysts following ICSI. As a positive or negative control, 0.3% BSA (mPZM-3) or 0.3% PVA (mPZM-4), respectively, was added to the base medium. The defined IVC medium was supplemented with 5 or 10 ng/ml EGE In Experiment 1, no significant difference was found in the rates of cleavage (31.4-64.3%) and blastocyst formation (6.5-22.9%) among the treatment and control groups. The mean cell numbers per blastocyst ranged from 30 to 48 among the groups without significant differences. However, in Experiment 2, the intracellular GSH concentrations in the oocytes cultured in the medium supplemented with 100 mc M Cys (9.6 pmol/oocyte) or Cys + cystine (9.9 pmol/oocyte) were significantly (p < 0.05) higher than the control (2.5 pmol/oocyte) and 0.6 mM cystine (6.5 pmol/oocyte) groups, but not different from the GV group (9.0 pmol/oocyte). The GSH concentration in the cystine group was also significantly (p < 0.05) higher than that in the control group, but not different from the GV group. In Experiment 3, the rates of cleavage and blastocyst formation and the mean cell numbers of blastocysts were not significantly different among the groups. However, the addition of 5 ng/ml EGF into the mPZM-4 resulted in a significantly (p < 0.05) higher blastocyst rate per cleaved embryo than the other two defined groups (mPZM-4 + 5 ng/ml: 48.6%, mPZM-4 and mPZM-4 +10 ng/ml: 23.4% and 23.1%, respectively). The present results indicate that the addition of Cys to a defined medium for in vitro maturation (IVM) of porcine oocytes increases intracellular GSH concentration. Further addition of cystine into the IVM medium containing 100 mc M Cys is not necessary and TCM199 plus Cys (100 PM) could be used as a defined IVM medium for porcine oocytes. The addition of 5 ng/ml EGF to a defined IVC medium has enhanced subsequent development after ICSI," wrote M. Kobayashi and colleagues, University of Agriculture.

The researchers concluded: "This study shows that porcine blastocysts can be produced by defined media throughout the steps of IVP (IVM, ICSI and IVC)."

Kobayashi and colleagues published their study in Zygote (Blastocyst production by in vitro maturation and development of porcine oocytes in defined media following intracytoplasmic sperm injection. Zygote, 2007;15(2):93-102).

For additional information, contact Y. Fukui, Obihiro University of Agriculture & Veterinary Medicine, Dept. of Animal Prod Science, Laboratory Animal Reproductive, Obihiro, Hokkaido 0808555, Japan.

Publisher contact information for the journal Zygote is: Cambridge University Press, 32 Avenue of the Americas, New York, NY 10013-2473, USA.

Keywords: Japan, Obihiro, Life Sciences, Cysteamine, Nephropathic Cystinosis Therapy, Radiation-Protective Agent, Glutathione, Dietary Supplement, Micronutrient, Zygote, University of Agriculture.

This article was prepared by Science Letter editors from staff and other reports. Copyright 2007, Science Letter via NewsRx.com.