Circumscribed lesion of the medial forebrain bundle area causes structural impairment of lymphoid organs and severe depression of immune function in rats

Abstract

Interactions between the immune system and the brain are a key element in the pathophysiology of diseases such as multiple sclerosis, neuroAIDS, and Alzheimer's, which affect large numbers of individuals and are associated with a high social cost. However, the neuroanatomical basis of brain-immune interactions has not been elucidated. We report that in Wistar rats of either sex bilateral electrolytic lesion of the medial forebrain bundle reduces body weight by 28% 7 days after lesioning, and causes widespread infections, aphagia, adypsia, structural damage to the lymphoid organs and heavy depression of T lymphocytes cytotoxicity. The following alterations occur in the immune system after those lesions: the weight of the thymus, spleen and lymphonodes is reduced by 77.9%, 49.1% and 48.4%, respectively. The thymus is atrophied and contains fewer lymphoid cells in the cortex than in the medulla. In the spleen the white pulp is reduced and lymphoid cells from periarteriolar zones and at the chords are almost absent. In lymph nodes cortical small lymphocytes are depleted and primary and secondary nodules and germinal centers all but disappear. Cytotoxicity of lymphocytes is reduced by 86.2% in the thymus, 77.6% in the spleen and 70.2% in lymph nodes. The critical area of lesion is at the medialmost portion of the medial forebrain bundle, at the preoptic area and rostral part of the anterior hypothalamus. We suggest that this area contains neural circuits that are crucial for keeping the structure of lymphoid organs and the functional integrity of the immune system.

Brain axonal and myelin evaluation in heart failure

“…Descending fibers of the medial forebrain bundle [51] and hippocampus have significant roles in mediating hedonic behavior, and the axonal changes here may contribute to these aspects.…”

Decreased in vitro production of interferon-gamma and interleukin-2 in whole blood of patients with schizophrenia during treatment

“…62,63 On the other hand, the number of studies is increasing that demonstrate lesions of hypothalamic structures lead to substantial disruptions of the immune system integrity. 64 However, considering that limited observations on the complex interactions of CNS tissue, neurotransmitters and cytokines are presently possible, caution must be exercised in interpreting psycho-immunological data, particularly since, despite considerable research, the mechanisms underlying the aberrant immune functions of PBMC from schizophrenics are as yet not understood at the cellular level.…”