Acute Electrical Stimulation of Nucleus Ambiguus Enhances Immune Function in Rats

Abstract

It is well known that there exists bidirectional regulation in the central nervous system (CNS) and immune system. [1][2][3] The CNS can have a widespread effect on the immune system following the activation of the hypothalamic-pituitary-adrenal axis 4,5 and the sympathetic nervous system. 3,6,7 Thus far, many regions in the brain such as the hypothalamic nuclei, brain reward system, limbic structures, cortex, midbrain periaqueductal gray matter, cerebellum, circumventricular organs, and vagal complex have been identified as "immunoactive" areas. 8 The nucleus ambiguous (Amb), that is a nucleus of the vagus nerve, is located in the ventrolateral reticulate structure of the medulla oblongata. Thus far, probably owing to traditional ideas regarding this area, study of the Amb ABSTRACT: Background: Up to now, many ''immunoactive'' brain areas have been identified, such as hypothalamic nuclei, brain reward system; but the nucleus ambiguous (Amb), a nucleus nervi vagis of medulla oblongata, was less well studied in neuroimmunomodulation. Methods: In order to obtain more profound comprehension and more knowledge on Amb, we studied the effect of acute electrical stimulation of Amb on thymus and spleen activity in rat. A stimulator was applied to stimulate the Amb of the anaesthetic rats using the parameter at 100μA×5ms ×100 Hz every 1s for 1 min. The levels of TGF-β and thymosin-β4 mRNA in thymus, the release of IL-2 and IL-6 at splenocyte in vitro and splenic lymphocyte proliferation were measured at hour 0.5,1,2,3 following the electrical stimulation. Results: The results showed that concanavalin A (Con A)-induced splenic lymphocyte proliferation and the release of IL-2 and IL-6 were all significantly enhanced at 0.5, 1, and 2 h following effective Amb stimulation as compared to in the control group. However, as compared to in the control group, the levels of TGF-β and thymosin-β4 mRNA in the thymus were both remarkably reduced at 0.5, 1, and 2 h following effective Amb stimulation. Conclusions: These findings reveal that the Amb participates in the modulation of animal immune functions.RÉSUMÉ: La stimulation électrique aiguë du noyau ambigu stimule la fonction immunitaire chez le rat. Contexte : Plusieurs zones immunoactives du cerveau ont été identifiées jusqu'à maintenant, dont les noyaux hypothalamiques (corps de Luys, noyau sous-thalamique), le système de récompense du cerveau. Cependant, il existe peu d'études sur le rôle du noyau ambigu (Amb), le noyau du nerf vague situé dans le bulbe rachidien, dans la neuro-immunomodulation. Méthodes

Timing of Applying Electrical Stimulation Is an Important Factor Deciding the Success Rate and Maturity of Regenerating Rat Sciatic Nerves

“…ES very soon after injury has generally been assumed to be most beneficial because ES-induced recovery can be facilitated by injuryinduced activation of the immune system. 6,7 ES can also accelerate upregulation of brain-derived neurotrophic factor (BDNF) and its receptor, trkB mRNA, which can support the development, maintenance, and plasticity of peripheral neurons. 8,9 Delayed onset of ES, then, may be less effective in promoting the recovery of regenerating nerves.…”