Ostreae Concha Extract Mitigates Sleep Disturbances Through 5-HT and Vagus Nerve-Mediated Gut-Brain Axis Pathways.

This study investigates the mechanism by which Ostreae Concha (OC), a traditional Chinese medicinal material derived from oyster shells, alleviates insomnia. A chronic insomnia mouse model was established and assessed using behavioral tests, Nissl staining, biochemical assays, immunofluorescence, and ELISA. The aqueous extract of OC improved locomotion and anxiety-like behaviors, increased hippocampal Nissl bodies, reduced brain malondialdehyde (MDA) levels, lowered plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT), and elevated 5-hydroxytryptamine (5-HT) and c-Fos expression in the nucleus of the solitary tract. In vitro experiments demonstrated that the inorganic components of OC enhanced the expression of proteins related to 5-HT synthesis, independently of calcium channels. Based on these findings, we propose that OC may form calcium carbonate nanoparticles in vivo, which stimulate intestinal chromaffin cells to release 5-HT. This signal is then transmitted via the vagus nerve to suppress overactivation of the hypothalamic-pituitary-adrenal (HPA) axis, thereby producing sedative and calming effects. The findings confirm OC's sedative and hypnotic effects by regulating the 5-HT system and HPA axis, consistent with its traditional application in treating insomnia. The inorganic components' role in 5-HT synthesis, independent of calcium channels, reveals a novel mechanism of OC. Additionally, OC's derivation from aquaculture waste highlights its potential in resource recycling, offering a basis for further development of OC-based sleep-improving products and ecological resource utilization. This work not only provides experimental evidence for the use of OC in sleep improvement but also suggests a potential pathway for the sustainable, high-value utilization of aquaculture waste, aligning ecological conservation with resource sustainability.