Chronic stress-induced brain injury (CSBI) is the organic damage of brain tissue caused by long-term psychological and environmental stress. However, there is no effective drug for the treatment of CSBI. The present study aimed to investigate possible mechanisms of CSBI and to explore related therapeutic targets. A rat model of CSBI was established by combining chronic restraint and cold water immersion. Our CSBI model was validated via Nissl staining, Western blotting, and behavioral tests. RNA sequencing (RNA-seq) was used to identify differentially expressed genes (DEGs) within brain tissue during CSBI. Both Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were performed to determine signaling pathways associated with CSBI-induced DEGs. Agonists/antagonists were used to validate the pharmacodynamics of potential therapeutic targets. A combination of chronic restraint and cold water immersion successfully induced a rat model of CSBI, as indicated by various markers of brain injury and cell apoptosis that were verified via Nissl staining, Western blotting, and behavioral tests. RNA-seq analysis identified 1,131 DEGs in CSBI rats. Of these DEGs, 553 genes were up-regulated and 778 genes were down-regulated. GO and KEGG pathway analyses revealed that significant DEGs were predominantly related to membrane-bound ion channels, among which the potassium channel function was found to be significantly affected. Pharmacological experiments revealed that retigabine, a voltage-gated potassium Biological and Pharmaceutical Bulletin Advance Publication channel opener, demonstrated a protective effect in CSBI rats. Taken together, our findings suggest that potassium channel function is disrupted in CSBI, and that potassium channel regulators may function as anti-CSBI drugs.

Saffron, a kind of rare medicinal herb with antioxidant, antitumor, and anti-inflammatory activities, is the dry stigma of Crocus sativus L. A new water-soluble endophytic exopolysaccharide (EPS-2) was isolated from saffron by anion exchange chromatography and gel filtration. The chemical structure was characterized by FT-IR, GC-MS, and 1D and 2D-NMR spectra, indicating that EPS-2 has a main backbone of (1→2)-linked α-d-Manp, (1→2, 4)-linked α-d-Manp, (1→4)-linked α-d-Xylp, (1→2, 3, 5)-linked β-d-Araf, (1→6)- linked α-d-Glcp with α-d-Glcp-(1→ and α-d-Galp-(1→ as sidegroups. Furthermore, EPS-2 significantly attenuated gentamicin-induced cell damage in cultured HEI-OC1 cells and increased cell survival in zebrafish model. The results suggested that EPS-2 could protect cochlear hair cells from ototoxicity exposure. This study could provide new insights for studies on the pharmacological mechanisms of endophytic exopolysaccharides from saffron as otoprotective agents