Effect of vestibular stimulation on cold water stress-induced neurological changes in Wistar rats

The current study was undertaken to see the effects of cold-water stress on the brain and to evaluate the beneficial effect of vestibular stimulation on stress-induced brain changes. Healthy, male, Wistar rats, weighing 180 to 250 gm with 3-6 months of age, were used for the study. Stress was induced by making the animals swim in cold water maintained at 100C for 30 min a day, for 14 days. Following cold water swimming stress, bilateral hot water caloric vestibular stimulation was given to the animals using 410C temperature water for 15 days. Rats were sacrificed and histopathological brain changes were studied by Hematoxylin & Eosin staining. Serum corticosterone level has increased significantly after cold water swimming stress (p<0.01). Corticosterone was less in animals that received caloric vestibular stimulation in comparison with the animals which did not receive caloric vestibular stimulation (p<0.05). Coldwater swimming stress had induced focal neuronal atrophy, nuclear pyknosis with congested blood vessels and infiltration of mononuclear inflammatory cells in the hippocampus and hypothalamus. Stressed animals that received caloric vestibular stimulation recovered well and showed the cerebral cortex with the normal neuroglial arrangement. Hypothalamus showed normal morphology and the hippocampus showed a pyramidal layer with a normal thickness in comparison to the animals which did not receive caloric vestibular stimulation. We conclude Caloric vestibular stimulation was effective in reversing the cold-water stress-induced serum corticosterone and histopathological changes in the brain.