Rhythmic expression of circadian clock genes in the preovulatory ovarian follicles of the laying hen

PLoS One. 2017 Jun 12;12(6):e0179019. doi: 10.1371/journal.pone.0179019. eCollection 2017.

Abstract

The circadian clock is reported to play a role in the ovaries in a variety of vertebrate species, including the domestic hen. However, the ovary is an organ that changes daily, and the laying hen maintains a strict follicular hierarchy. The aim of this study was to examine the spatial-temporal expression of several known canonical clock genes in the granulosa and theca layers of six hierarchy follicles. We demonstrated that the granulosa cells (GCs) of the F1-F3 follicles harbored intrinsic oscillatory mechanisms in vivo. In addition, cultured granulosa cells (GCs) from F1 follicles exposed to luteinizing hormone (LH) synchronization displayed Per2 mRNA oscillations, whereas, the less mature GCs (F5 plus F6) displayed no circadian change in Per2 mRNA levels. Cultures containing follicle-stimulating hormone (FSH) combined with LH expressed levels of Per2 mRNA that were 2.5-fold higher than those in cultures with LH or FSH alone. These results show that there is spatial specificity in the localization of clock cells in hen preovulatory follicles. In addition, our results support the hypothesis that gonadotropins provide a cue for the development of the functional cellular clock in immature GCs.

MeSH terms

  • Animals
  • Cells, Cultured
  • Chickens / physiology*
  • Circadian Clocks / genetics*
  • Circadian Rhythm / genetics*
  • Female
  • Follicle Stimulating Hormone / pharmacology
  • Gene Expression Regulation* / drug effects
  • Granulosa Cells / metabolism
  • Luteinizing Hormone / pharmacology
  • Ovarian Follicle / metabolism*
  • Ovulation / genetics*
  • Period Circadian Proteins / genetics
  • Theca Cells / metabolism

Substances

  • Period Circadian Proteins
  • Luteinizing Hormone
  • Follicle Stimulating Hormone

Grants and funding

This work was financially supported by the China Agriculture Research System (CARS-41) (http://cyjstx.sdny.gov.cn/); The Twelfth Five Year Plan for Breeding Program in Sichuan (2011NZ0099-7) (http://www.sc.gov.cn/) and the thirteenth Five Year Plan for Breeding Program in Sichuan (16ZC2838) (http://www.sc.gov.cn/) to QZ. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.