Endometrial glycogen metabolism during early pregnancy in mice

In humans, at least 30-40% of pregnancies fail, most during the preimplantation period. Before implantation, too much or too little glucose impairs embryo development. Pregnancy also requires successful decidualization of the stroma, a glucose intensive process. Therefore, optimal levels of endometrial glucose are required to achieve a successful pregnancy. Glycogen, the storage form of glucose, is found in the uterus and may contribute to maintaining glucose concentrations. Our objectives were to 1) determine how glycogen levels change in the luminal epithelium, glandular epithelium, and stroma during early pregnancy; 2) understand the distribution of glycogen metabolizing enzymes (hexokinase I, HK1; glucose-6-phosphatase, G6PC; glycogen synthase, GYS; and glycogen phosphorylase, PYG); and 3) determine if the decidua stores glycogen independently of pregnancy. To characterize glycogen during pregnancy, uteri from CD-1 mice were collected at proestrus, days post-coitum 1.5 (DPC 1.5), DPC 3.5, and DPC 5.5. To artificially induce decidualization, CD-1 mice were ovariectomized, primed with steroids, and one uterine horn was stimulated by an infusion of corn oil. Periodic acid-Schiff staining, with and without diastase pre-treatment, was used to measure glycogen content in endometrial tissues. Western blot was carried out to quantify glycogen metabolizing enzymes. Immunohistochemistry (IHC) was performed to localize the glycogen metabolizing enzymes. Our results showed that in the glandular epithelium, glycogen content was highest at proestrus and decreased 71.4% at DPC 1.5 and 62.13% at DPC 3.5. Similarly, in the luminal epithelium glycogen was highest at proestrus, was 46.2% lower at DPC 1.5 and 63.2% lower at DPC 3.5. In contrast, the stroma stored little glycogen during the preimplantation period, and the amount did not change. However, at DPC 5.5, glycogen content increased 7-fold in the implantation site compared to the stroma of proestrus. IHC showed that HK1 was present in the glandular and luminal epithelium, but was undetectable in the stroma. GYS in the luminal and glandular epithelium was highest in the preimplantation period compared to proestrus, but was not detected in stromal cells. At the implantation site, there was a dramatic increase in GYS in the decidua. G6PC was highly expressed in the luminal and glandular epithelium from DPC 1.5 to DPC 5.5. PYG increased from proestrus to DPC 3.5 in the glandular and luminal epithelium. The artificially decidualized stroma showed a 5-fold increase in glycogen content. The levels of GYS, G6PC, and PYG were increased in the decidualized uterine horn compared to the control horn. In conclusion, glycogen in the luminal and glandular epithelium of murine uterus decreased during early pregnancy, which correlated with the increased expression of G6PC and PYG. This suggests that glycogen in the uterine epithelium supports the preimplantation embryos. In contrast, glycogen in the stroma was constantly low until after implantation. After which, glycogen and GYS expression increased dramatically in the decidua. Thus, the decidua stores glycogen, which later may be released to support remodelling of the decidua or to provide energy for embryo development.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Chen, Ziting

Contributors dc:contributor

• Dean, Matthew
• Nowak, Romana
• Miller, David

• Uterus
• Preimplantation
• Implantation
• Decidualization

Statement dc:rights

• Copyright 2022 Ziting Chen

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115794

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115794