Effects of myo-inositol on the in-vitro maturation and subsequent development of mouse oocytes.
BACKGROUND
The study aim was to assess whether the incorporation of myo-inositol (MI) into culture medium could improve oocyte maturation in vitro.


RESULTS
We performed a controlled prospective study using female ICR strain mice superovulated with pregnant mare's serum gonadotrophins. Cumulus-enclosed germinal vesicle (GV) oocytes were randomly cultured in medium with or without MI supplementation. The kinetics of GV breakdown after 4 h of incubation was significantly higher in oocytes incubated with 30 mmol/l of MI than in controls (P < 0.001). Accordingly, this concentration of MI was used for subsequent experiments. The proportion of metaphase II oocytes achieved after 24 h of culture, their fertilization and cleavage rates were significantly higher in the MI-treated group (P < 0.01, P < 0.05, P < 0.05 respectively). This group also demonstrated significant improvement in postimplantation development after transferring the 2-cell embryos to pseudopregnant mice. Confocal microscopy revealed spontaneous intracellular Ca(2+) oscillations within competent GV oocytes and treatment with MI caused an earlier onset of these Ca(2+) signals.


CONCLUSIONS
Our results suggest that MI may affect meiotic progression of mouse GV oocytes possibly by enhancing the intracellular Ca(2+) oscillations. Supplementation of MI in culture medium may be useful for human oocyte maturation.
Chiu
Tony Tak Yu
TT
Department of Obstetrics & Gynaecology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China. tonychiu@cuhk.edu.hk
Rogers
Michael Scott
MS
Briton-Jones
Christine
C
Haines
Christopher
C
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000187:drug effects; D003470:Culture Media; D005260:Female; D005307:Fertilization in Vitro; D007294:Inositol / Q000008:administration & dosage / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects; D051379:Mice; D009865:Oocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D009991:Oscillometry; D006080:Ovarian Follicle / Q000166:cytology; D016896:Treatment Outcome
D003470:Culture Media; D007294:Inositol; D002118:Calcium