Mathematical modeling of glucose supply toward successful in vitro maturation of Mammalian oocytes

In vitro maturation-whereby an oocyte is harvested from an ovary just before full maturation, matured in the laboratory, fertilized, and then transplanted back to the uterus-has important benefits over, but is significantly less successful than, traditional in vitro fertilization. Inadequate in vitro nutrient environments are believed to be a prime reason for the low success, but understanding of the in vivo environment, which needs to be better replicated in the laboratory, is still lacking. We here consider mathematical modeling as an aid to increasing that understanding. A general mathematical model suitable for examining the in vivo concentrations of a nutrient in the cumulus-oocyte complex (COC) is presented. We then tailor the model to consider glucose concentration. Experimental data are used to obtain information on glucose uptake in the COC for use in the model. Finally, we solve the model to estimate glucose concentration in the COC. With the information currently available, the model indicates a significant reduction in glucose concentration from the follicular fluid across the cumulus matrix to the oocyte.