Diazepam Inhibits Proliferation of Lymph Node Cells Isolated from Rats with Experimental Autoimmune Encephalomyelitis

Abstract

Objective: Experimental autoimmune encephalomyelitis (EAE) is an inflammatory demyelinating disease with similarities to human multiple sclerosis involving peripheral activation of autoreactive T cells which infiltrate the central nervous system and react to self antigens leading to damage. In previous studies, we have demonstrated that treatment with diazepam decreases the incidence and histological signs associated with the disease and diminishes immunological responses. The aim of the present work was to evaluate direct effects of diazepam on isolated T cells involved in immune responses during the development of EAE. Methods: Animals were sensitized with whole myelin to induce EAE and sacrificed during the acute phase of the disease. In mononuclear cells isolated from popliteal lymph nodes, cell viability, apoptosis induction, proliferation and cytokine production were evaluated. Results: Diazepam did not have a toxic or proapoptotic effect on the cells, at least up to the concentration of 25 μ<smlcap>M</smlcap>, but proliferation, CD8+ T-cell activation and proinflammatory cytokine production were dose-dependently decreased. Conclusions: Diazepam has a direct inhibitory effect on the proliferation and activation of T lymphocytes isolated from the main lymphoid organ involved in disease onset and this could be one of the mechanisms that contribute to the beneficial effect previously observed with diazepam in vivo during EAE development.

Midazolam’s Effects on Delayed-Rectifier K+ Current and Intermediate-Conductance Ca2+-Activated K+ Channel in Jurkat T-lymphocytes

“…To what extent the IK Cachannel activity in astrocytes contributes to MDZ mediated regulation of apoptotic changes thus remains to be further determined. Taken together, despite the detail mechanism of MDZ actions on these K + channels being unclear, if similar findings are observed in lymphocytes occurring in cell culture or in vivo to those described herein, the actions of MDZ or its functionally related agents (e.g., diazepam) observed in the present study will result in significant changes in immune reactions [2,[4][5][6]23] Israel). For cell preparations, culture media, fetal bovine serum (FBS), L-glutamine, trypsin/EDTA, penicillin-streptomycin, and amphotericin B were obtained from Invitrogen (Carlsbad, CA, USA).…”

“…Assuming that periodical changes in membrane potential of inner mitochondrial membranes may take place [44], the issue of whether blockade of mitochondrial K V 1.3 channels caused by MDZ is responsible for its effects on Bax-K V 1.3 interactions [23,37] is worthy of being investigated. Nonetheless, because of the importance of I K(DR) (i.e., K V 1.3-encoded current) in contributing to functional activities of lymphocytes [19,36], the effects presented herein could provide novel insights into pharmacological or immunological properties of MDZ and other structurally related compounds (e.g., diazepam) [1,2,[4][5][6]9,20,45].…”

“…It belongs to a group known as benzodiazepines, which are known to act on the central nervous system (CNS). In addition, being a CNS sedative drug, there are growing reports showing that this compound could influence mammalian immune function both in cell culture and in vivo [1][2][3][4][5][6][7][8][9]. More interestingly, it has been demonstrated to activate the intrinsic pathways of apoptotic changes through elicitation of the mitochondrial pathway [10,11].…”

Diazepam Impairs Innate and Adaptive Immune Responses and Ameliorates Experimental Autoimmune Encephalomyelitis

“…Moreover, the goal of this work was to evaluate the ability of DZ to suppress the different phases of the immune responses. We suggest that DZ could affect not only the maturation of APCs and their ability to initiate adaptive responses, but it could also have an effect on the expansion and proliferation of antigen-specific T cells as we have previously shown (12). Therefore, herein we demonstrated that DZ suppressed established inflammatory responses in vitro.…”

“…Upregulation of the TSPO is observed in many CNS diseases, and some TSPO ligands are currently under investigation as therapeutic means for promoting neuroprotection, axonal regeneration, and modulating inflammation (6,7). Diazepam (DZ), which is a mixed-type benzodiazepine that can act on both central and peripheral benzodiazepine receptors, has been demonstrated to have an inhibitory effect on T cell function (8)(9)(10)(11)(12). However, the action on professional antigenpresenting cells such as macrophages (Mfs) and dendritic cells (DCs) is not well characterized.…”