Hypoglossal Nerve Transection Induces Anxiety- and Depression-like Behaviors with HPA Axis Dysregulation in Rats

This study investigated whether tongue motor loss induced by bilateral transection of the hypoglossal nerves (Hx) alters anxiety- and/or depression-like behaviors in rats and examined the associated neuroendocrine changes. Male Sprague-Dawley rats underwent Hx or sham surgery and were evaluated in the ambulatory activity, elevated plus maze, forced swim, and sucrose preference tests at different postoperative time points. Neuroendocrine parameters were assessed by plasma corticosterone assay, quantitative real-time PCR, Western blot analysis, and adrenal histology. At two weeks after surgery, Hx rats exhibited anxiety-like behavioral changes in the elevated plus maze and increased immobility with reduced struggling in the forced swim test, consistent with a depression-like behavior. Reduced sucrose intake was observed at earlier postoperative stages, suggesting early anhedonia-like behavior. Hx rats also showed chronically increased plasma corticosterone levels, adrenocortical hypertrophy, and decreased hippocampal glucocorticoid receptor expression. These findings highlight a potential oral-systemic interaction in which loss of oral motor function alters neuroendocrine homeostasis and emotional regulation.