The intergenerational effects of glucose enrichment on the reproduction of C. elegans
Date
2024
Authors
Bass, Elizabeth
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Abstract
Despite glucose being shown to have detrimental effects on reproduction, the intergenerational impacts of diet on reproduction have not been well investigated. The ‘Fetal Origins of Disease’ hypothesis suggests that a parent's environment affects the health of the offspring in their adult life. Therefore, I hypothesized that offspring that remain on the same media as their parents will be better suited to that environment and, therefore, better able to reproduce later in life. I used Caenorhabditis elegans to test this hypothesis. The parental generation of C. elegans lived on nematode growth medium (NGM) or NGM supplemented with 20 mM glucose for two days. Fertilized oocytes were taken from these individuals and served as the offspring generation. The offspring were raised on NGM before being placed on one of the experimental mediums. Four experimental groups were created: an NGM to NGM group, an NGM to glucose group, a glucose to glucose group and a glucose to NGM group. A late mating assay was completed to determine each group's reproductive ability and oocyte quality analysis using DIC of mated hermaphrodites on Day 5 of adulthood. Significant differences suggested that exposure to glucose only in the parental generation or only in the offspring generation negatively impacted the late-reproductive capacity of the offspring. The late-reproductive capacity of worms exposed to glucose for two generations was significantly better than that of those exposed to glucose only in the offspring generation. This suggests that prior parental exposure to glucose may be beneficial for living in a high-glucose environment. Assessment of oocyte quality based on the presence of cavities between oocytes, regularity of shape and reduction in oocyte size also produced significant differences between groups. Exposure to glucose only in the offspring generation significantly decreased the size of the oocytes and increased the presence of cavities compared to those not exposed to glucose. Exposure to glucose only in the parent generation significantly reduced the size of the oocytes. No significant differences were found in the regularity of shape between each group. These results suggest that exposure to glucose decreases reproductive capacity later in life, partially due to decreased oocyte quality. The effects of glucose exposure in the parent generation may result in epigenetic changes that can be harmful if the offspring returns to an NGM diet but may be beneficial if the offspring remains on the diet.