Vagus nerve stimulation alleviates anxiety by inhibiting ferroptosis-related neuronal damage through α7nAChR

Anxiety disorder is a highly prevalent mental health issue globally; however, existing therapeutic approaches have limitations such as significant side effects and poor compliance. Vagus nerve stimulation (VNS) has been used to treat emotional distress, while the underlying mechanisms remain elusive.

A chronic restraint stress (CRS)-induced mouse anxiety model in vivo and a corticosterone (CORT)-induced neuronal cell death model in vitro were employed, followed by treatment with vagus nerve stimulation and α7nAChR agonists or antagonists. Anxiety levels were assessed using the open field test (OFT), elevated plus maze (EPM), and novelty-suppressed feeding test (NSFT). Histopathological staining and immunofluorescence staining were performed to detect the pathological changes of neuronal injury in anxiety disorders. Western blot was conducted to measure the protein expression levels of GPX4, SLC7A11, and ACSL4. Enzyme-linked immunosorbent assay (ELISA) was used to measure the expression levels of anxiety-related pro-inflammatory cytokines, while quantitative real-time polymerase chain reaction (qPCR) was employed to detect the mRNA expression levels of GPX4, SLC7A11, and ACSL4.

In this study, we found that VNS significantly alleviated anxiety-like behaviors, reduced hippocampal ferroptosis-related damage and inflammatory responses in anxiety mice. α7nAChR antagonist abolished VNS-mediated protective effects against ferroptosis-related neuronal damage and anxiety, while α7nAChR agonists produced similar anxiolytic effects to VNS. Mechanistically, VNS activated α7nAChR signaling, thereby upregulating the expression of GPX4 and SLC7A11, inhibiting ACSL4-mediated lipid peroxidation, and ultimately suppressing anxiety-induced ferroptosis-related neuronal damage.

This study reveals a novel mechanism underlying the anxiolytic effect of VNS, that is, by activating α7nAChR signal, VNS inhibits CRS-induced ferroptosis-related neural damage. Our findings provide new insights into mechanism of anxiety disorders and lay a theoretical foundation for the clinical application of VNS.