Chlorella vulgaris reduces the impact of stress on hypothalamic-pituitary-adrenal axis and brain c-fos expression

Psychoneuroendocrinology. 2016 Mar;65:1-8. doi: 10.1016/j.psyneuen.2015.12.002. Epub 2015 Dec 4.


Predominantly emotional stressors activate a wide range of brain areas, as revealed by the expression of immediate early genes, such as c-fos. Chlorella vulgaris (CV) is considered a biological response modifier, as demonstrated by its protective activities against infections, tumors and stress. We evaluated the effect of acute pretreatment with CV on the peripheral and central responses to forced swimming stress in adult male rats. Pretreatment with CV produced a significant reduction of stress-related hypothalamic-pituitary-adrenal activation, demonstrated by decreased corticotrophin releasing factor gene expression in the hypothalamic paraventricular nucleus (PVN) and lower ACTH response. Hyperglycemia induced by the stressor was similarly reduced. This attenuated neuroendocrine response to stress occurred in parallel with a diminished c-fos expression in most evaluated areas, including the PVN. The data presented in this study reinforce the usefulness of CV to diminish the impact of stressors, by reducing the HPA response. Although our results suggest a central effect of CV, further studies are necessary to understand the precise mechanisms underpinning this effect.

Keywords: ACTH; Chlorella vulgaris; Corticosterone; Corticotropin-releasing factor; Forced swimming; Glucose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenocorticotropic Hormone / drug effects
  • Adrenocorticotropic Hormone / metabolism
  • Animals
  • Brain / metabolism
  • Brain / physiology*
  • Chlorella vulgaris*
  • Corticosterone / metabolism
  • Corticotropin-Releasing Hormone / drug effects
  • Corticotropin-Releasing Hormone / metabolism
  • Genes, fos
  • Hypothalamo-Hypophyseal System / drug effects*
  • Hypothalamo-Hypophyseal System / metabolism
  • Hypothalamus / metabolism
  • In Situ Hybridization
  • Male
  • Paraventricular Hypothalamic Nucleus / metabolism
  • Pituitary-Adrenal System / metabolism
  • Pituitary-Adrenal System / physiology*
  • Proto-Oncogene Proteins c-fos / biosynthesis*
  • Proto-Oncogene Proteins c-fos / genetics
  • Proto-Oncogene Proteins c-fos / metabolism
  • RNA, Messenger / metabolism
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Stress, Physiological / physiology*
  • Stress, Psychological / genetics
  • Stress, Psychological / metabolism
  • Swimming


  • Proto-Oncogene Proteins c-fos
  • RNA, Messenger
  • Adrenocorticotropic Hormone
  • Corticotropin-Releasing Hormone
  • Corticosterone