Presentation Title

Photoperiod differentially regulates ovarian matrix components in Siberian hamsters (Phodopus sungorus).

Faculty Mentor

Kelly A. Young

Start Date

23-11-2019 10:00 AM

End Date

23-11-2019 10:45 AM

Location

69

Session

poster 3

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Seasonal breeders, including Siberian hamsters (Phodopus sungorus), synchronize their reproductive function to the time of the year that optimizes offspring survival via measuring and responding to changes in photoperiod, or the length of daylight within a 24h period. Exposing seasonally-breeding Siberian hamsters to inhibitory short days (SD, 8hrs of light; 16hrs of dark), decreases pituitary release of gonadotropins, resulting in the regression of ovarian function, whereas, transfer from SD to long days (LD, 16L:8D) restores gonadotropin release which subsequently reinstates ovarian function in a process called recrudescence. While the impact of folliculogenic factors on recrudescence has been well-studied, little is known about the role of ovarian stromal matrix during these photoperiod-mediated changes in ovarian function. The ovarian stroma is constantly in flux to adapt to and influence the changing stages of follicle development. We hypothesized that matrix components, including versican, hyaluronidase, and collagen would 1) be present in Siberian hamster ovaries and 2) would change with exposure to one of five different photoperiod regimes: LD, SD, or recrudescing females transferred from SD to LD for 2, 4, or 8 weeks (post transfer groups, PT). Collagen quantity, assessed via trichome staining, was significantly higher in LD compared to SD and PTwk2 groups (p<0.05) and was restored to LD levels at PTwk4. Versican followed a similar pattern where there was a significant decrease in versican mRNA levels in the SD ovaries compared to all other groups when assessed by real time PCR (p<0.05). Lastly, hyaluronidase-2 mRNA levels increased during restoration of ovarian function; levels were significantly higher in PTwk8 compared to all other groups (p<0.05). Additional experiments are needed to distinguish if the photoperiod-induced changes observed in the ovarian stromal microenvironment are the result of the changes observed in folliculogenesis or if the matrix changes can themselves directly impact ovarian function.

This document is currently not available here.

Share

COinS
 
Nov 23rd, 10:00 AM Nov 23rd, 10:45 AM

Photoperiod differentially regulates ovarian matrix components in Siberian hamsters (Phodopus sungorus).

69

Seasonal breeders, including Siberian hamsters (Phodopus sungorus), synchronize their reproductive function to the time of the year that optimizes offspring survival via measuring and responding to changes in photoperiod, or the length of daylight within a 24h period. Exposing seasonally-breeding Siberian hamsters to inhibitory short days (SD, 8hrs of light; 16hrs of dark), decreases pituitary release of gonadotropins, resulting in the regression of ovarian function, whereas, transfer from SD to long days (LD, 16L:8D) restores gonadotropin release which subsequently reinstates ovarian function in a process called recrudescence. While the impact of folliculogenic factors on recrudescence has been well-studied, little is known about the role of ovarian stromal matrix during these photoperiod-mediated changes in ovarian function. The ovarian stroma is constantly in flux to adapt to and influence the changing stages of follicle development. We hypothesized that matrix components, including versican, hyaluronidase, and collagen would 1) be present in Siberian hamster ovaries and 2) would change with exposure to one of five different photoperiod regimes: LD, SD, or recrudescing females transferred from SD to LD for 2, 4, or 8 weeks (post transfer groups, PT). Collagen quantity, assessed via trichome staining, was significantly higher in LD compared to SD and PTwk2 groups (p<0.05) and was restored to LD levels at PTwk4. Versican followed a similar pattern where there was a significant decrease in versican mRNA levels in the SD ovaries compared to all other groups when assessed by real time PCR (p<0.05). Lastly, hyaluronidase-2 mRNA levels increased during restoration of ovarian function; levels were significantly higher in PTwk8 compared to all other groups (p<0.05). Additional experiments are needed to distinguish if the photoperiod-induced changes observed in the ovarian stromal microenvironment are the result of the changes observed in folliculogenesis or if the matrix changes can themselves directly impact ovarian function.