Semester of Graduation

Summer 2025

Degree

Master of Science (MS)

Department

School of Animal Sciences

Document Type

Thesis

Abstract

The mammalian oviduct is the site of oocyte fertilization and early embryo development, including EGA. Therefore, a suboptimal oviduct microenvironment can disrupt early embryo epigenetic programming, with potential long-term health consequences in adulthood, consistent with the DOHaD paradigm. Due to the ethical and technical constraints of in vivo oviduct research, we used BOEO as a model. Organoids are 3D in vitro systems that closely recapitulate key in vivo characteristics, including IOF composition, which closely mimics the tissue of origin luminal fluid.

Cannabis is the most common drug among women of reproductive age in the United States, with rising use during pregnancy. This trend is concerning as prenatal cannabinoid use is associated with adverse offspring outcomes (DOHaD). We tested the overarching hypothesis that maternal cannabis exposure – via circulating primary metabolites CBD and THC – indirectly affects early embryo epigenetic programming, by altering oviduct epithelial secretions.

BOEO were derived from synchronized crossbred beef cattle (n=4) oviducts postmortem on Day 5 of the estrous cycle. Following cryopreservation, a single sub-culture, and a 14-day growth period, BOEO were supplemented for 3 days with (a) E2, (b) a P4 analogue [MPA], or (c) negative control (base media). Additional groups received (d) vehicle control (CH3OH), (e) E2+MPA, or (f) E2+MPA+CBD+THC for 6 days. BOEO were imaged every 24 h during treatment, followed by morphological assessment, IHC/IF, gene expression analysis (RNA sequencing), and IOF metabolomic profiling. BOEO expressed the epithelial marker cytokeratin, OVGP1, and cannabinoid receptors CB1 and CB2. Hormonal responsiveness was confirmed by DEG profiles. Notably, THC+CBD exposure induced distinct changes in BOEO gene expression and IOF composition, including elevated 5dA. To evaluate potential downstream effects, bovine embryos were then cultured with 5dA, resulting in embryonic global hypomethylation. In summary, maternal cannabinoid exposure alters oviduct epithelial secretions in vitro, leading to metabolic changes that impair embryonic epigenetic programming via an indirect, oviduct-mediated mechanism.

Date

7-10-2025

Committee Chair

Simintiras, Constantine

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