Investigation of the antidepressant effects of exopolysaccharides obtained from Marasmius androsaceus fermentation in a mouse model.

Marasmius androsaceus, a well‑known medical fungus, possesses antihypertensive, analgesic and antioxidant effects. Exopolysaccharide (EPS), produced by microorganism secretion, exerts various types of biological activities. The present study aimed to investigate the antidepressant‑like effect of the EPS produced during Marasmius androsaceus submerge fermentation (MEPS). Based on the assessment of acute toxicity and behavior, a forced swimming test (FST), tail suspension test (TST), 5‑hydroxytryptophan‑induced head‑twitch assessment and reserpine‑induced hypothermia assessment were performed. The administration of MEPS for 7 days enhanced mouse locomotor and balance ability in the mice. Similar to the results following treatment with fluoxetine, which was used as positive control drug, MEPS significantly decreased the duration of immobility in the FST and TST, increased head twitches in the 5‑HTP‑induced head‑twitch test and enhanced rectal temperature in resperpine‑induced hypothermia. MEPS altered the abnormal concentrations of 5‑hydroxytryptamine, 5‑hydroxyindoleacetic acid, dopamine and norepinephrine in the hypothalamus in the resperine‑induced mouse model. Additionally, an increase in the expression of tyrosine hydroxylase and a reduction in the level of dopamine transporter in the hypothalamus were noted following 7 days of MEPS administration. Taken together, the EPS produced during MEPS exhibited antidepressant‑like effects, which may be associated with its regulation on the dopaminergic system. The results of the present study provide experimental evidence supporting the clinical use of MEPS as an effective agent against depression.