The traditional herbal medicine,
Hochu-ekki-to, has been shown to have preventive effects on
viral infection and stress. This study aimed to evaluate the clinical effects of
Hochu-ekki-to on two stress-related rat models of
polycystic ovarian syndrome. Female Sprague-Dawley rats were divided into control and treatment groups, the latter of which were subjected to stress induced by exposure to
adrenocorticotropic hormone (
ACTH) or cold temperatures. After these stress inductions, rats were orally treated with dissolved
Hochu-ekki-to once per day for 7 days. Rats subjected to the two different stressors exhibited upregulation of
steroid hormone receptors (in ovaries) and reproductive
hormones (in blood), and consequent stimulation of abnormal follicle development accompanied by elevation of Hsp 90 expression (in ovaries). Treatment with
Hochu-ekki-to for 7 days after stress induction increased immune functions, reduced the stress-induced activation of Hsp 90, and normalized the levels of the tested
steroid hormone receptors and reproductive
hormones. Our findings suggest that stress stimulations may promote the activation of Hsp 90 via the dysregulation of
steroid hormone receptors and reproductive
hormones, but that post-stress treatment with
Hochu-ekki-to improves reproductive and immune functions in the ovaries of stressed rats.