Paeonol alleviates postmenopause-induced neuropsychiatric symptoms through the modulation of GPR30 in ovariectomized mice

The Moutan cortex (MC), the root bark of Paeonia suffruticosa Anderws (Paeoniaceae), has been historically employed in traditional herbal medicine for addressing women's ailments by replenishing kidney Yin. We aimed to explore if paeonol, an active constituent of MC, could ameliorate neuropsychiatric symptoms, such as anxiety, depression, and cognitive impairments, associated with post-menopausal syndrome (PMS) in an ovariectomized (OVX) mouse model. The experimental design comprised 6 groups, including a sham group, OVX group, paeonol administration groups (3, 10 or 30 mg/kg, p.o.), and an estradiol (E2)-treated positive control group. Behavioral tests including the open field, novel object recognition, Y-maze, elevated plus-maze, splash, and forced swimming tests were conducted. In addition, we investigated the effets of paeonol on the phosphorylated levels of phosphatidylinositol 3-kinase (PI3K), Akt, and mammalian target of rapamycin (mTOR), as well as on the expression levels of G protein-coupled receptor (GPR30) and brain-derived neurotrophic factor (BDNF) in the prefrontal cortex and hippocampus. Paeonol treatment (10 and 30 mg/kg, p.o.) effectively reversed the cognitive decline in OVX mice, measured by the novel object recognition and Y-maze tests, similar to that in the positive control group. Additionally, it alleviated anxiety- and depressive-like behaviors, as evaluated by the elevated plus-maze test, splash test, and forced swimming test. Paeonol restored GPR30 expression levels in the prefrontal cortex and hippocampus, mirroring the effects of E2 administration. Furthermore, it reversed the reduced expression levels of the PI3K-Akt-mTOR signaling pathway in the prefrontal cortex and hippocampus and increased BDNF expression in the hippocampus of OVX mice. This research suggests that paeonol would be beneficial for alleviating PMS-associated cognitive impairment, anxiety and depression.