Dietary sugar in healthy female primates perturbs oocyte maturation and in vitro preimplantation embryo development

Abstract

The consumption of refined sugars continues to pose a significant health risk. However, nearly nothing is known about the effects of sugar intake by healthy women on the oocyte or embryo. Using rhesus monkeys, we show that low-dose sucrose intake over a 6-month period has an impact on the oocyte with subsequent effects on the early embryo. The ability of oocytes to resume meiosis was significantly impaired, although the differentiation of the somatic component of the ovarian follicle into progesterone-producing cells was not altered. Although the small subset of oocytes that did mature were able to be fertilized in vitro and develop into preimplantation blastocysts, there were >1100 changes in blastocyst gene expression. Because sucrose treatment ended before fertilization, the effects of sugar intake by healthy primates are concluded to be epigenetic modifications to the immature oocyte that are manifest in the preimplantation embryo.

Figure 1.

Long-term treatment of healthy primates with sucrose inhibits meiotic resumption. A, Oral sucrose (Su) treatment did not alter the total number of oocytes recovered after controlled ovarian stimulation and hCG administration compared with that for controls (labeled C), but significantly reduced the percentage of oocytes that resumed meiosis (B). C, Circulating concentrations of progesterone after an ovulatory stimulus were not altered by sucrose. Values are means ± SEM (n = 6 or 7 for control and sucrose) *, Significantly different from control.

Figure 2.

Quantitative analysis of selected cumulus cell mRNAs. The 5 mRNAs were selected for analysis based on a magnitude of change, biological function, and raw intensity of values on the array. Array values for each gene are shown with black bars, and qRT-PCR changes are shown in gray; both are represented as the fold change in expression (sucrose/control). The qRT-PCR data represent the means ± SEM (n = 3).