The effects of propylparaben on preimplantation embryo development

Parabens are chemicals that have been widely used in personal care products and food as antimicrobial preservatives. They are synthesized as a series of parahydroxybenzoates or esters of parahydroxybenzoic acid. Parabens are known to have potential estrogenic activity as they can bind to both estrogen receptor 1 (ESR1) and -2 (ESR2) and are therefore classified as endocrine disrupting chemicals. With substantial numbers of women consumers exposed to parabens daily, there is a need to investigate the effects of parabens on the female reproductive system. A previous study in a mouse model found that development of the ovaries was impacted by exposure to parabens, with an increase in cystic follicles, decrease in corpora lutea, and thinning of the follicular epithelium. The effects of parabens on embryo development have not been studied extensively. The goal of the present study was to determine the impact of propylparaben exposure on preimplantation embryo development, our specific endpoints were the rate of development to the hatched blastocyst stage; number of inner cell mass and trophectoderm cells; and distribution of cytoskeletal F-actin in cultured mouse embryos. To analyze propylparaben effects on embryo development, concentrations of 0, 0.5μg/mL, 5.0 μg/mL, 10 μg/mL and 15 μg/mL propylparaben were tested. Five- to six-week-old female CD-1 mice were superovulated and placed with B6D2F1 male mice for mating. After 21 hours, the embryos were collected and transferred to either control medium, vehicle control (DMSO 0.075%) or various doses of propylparaben in treatment drops for embryo culture and monitored until the hatched blastocyst stage. Hatched blastocysts were collected and immunofluorescence staining was performed. Primary antibodies OCT-4 and CDX-2 were used to identify inner cell mass (ICM) and trophectoderm (TE) cells respectively. Phalloidin staining was used to identify the F-actin network in the hatched blastocyst. The percentage hatched blastocysts were significantly decreased at 10 μg/mL (23.40% hatched) and 15μg/mL propylparaben (13.04% hatched) compared to vehicle control (40.76% hatched). Propylparaben treatment had no significant effects on TE number. However, treatment with 0.5 µg/mL and 15μg/mL propylparaben significantly decreased the numbers of ICM cells when compared to vehicle control. The intensity of the phalloidin fluorescence staining was significantly decreased at the 10μg/mL and 15μg/mL propylparaben treatments when compared to vehicle control. In summary, our findings show that propylparaben exposure, at certain doses, disrupts ICM formation, impacts cytoskeletal F-actin network formation and alters hatched blastocyst development rate. These results suggest that exposure of embryos to elevated levels of parabens either in vivo or in vitro needs to be minimized.

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

• Lai, Nastasia Zhen Ee

Contributors dc:contributor

• Nowak, Romana A
• Flaws, Jodi A
• Ziv-Gal, Ayelet

• reproductive toxicology
• paraben
• propylparaben
• female
• reproduction
• embryo
• development

Statement dc:rights

• Copyright 2022 Nastasia Lai

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/115784

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F115784