Dehydroleucodine and xanthatin as potential therapeutic strategies for neuropathic pain: role of mast cells

MARIANI ML; VARGAS PM; COLL R; PENISSI AB

Simposio; II Simposio Internacional de Medicina Traslacional; 2019

Neuropathic pain is a clinical condition characterized by a series of cellular and molecular events that comprise inflammatory and immune mechanisms, such as the activation of macrophages, mast cells and other cells of the immune system. The release of inflammatory preformed mediators and the increase of the gene expression of proinflammatory cytokines are also involved in this response. Neurogenic inflammation -- one of the neurochemical substrates of neuropathic pain -- is stimulated by the release of proinflammatory neuropeptides, like substance P, neurotensin and neuromedin, from injured or dysfunctional nervous tissue. Mast cells are among the main cell types responsible for neurogenic inflammation2-4 and are defined as connective tissue specialized cells that release a great variety of biologically active mediators such as serotonin in response to the activation by immunological and non-immunological stimuli. They play an essential role in the origin and modulation of the cellular inflammatory response. Several experimental pieces of evidence prove that they are important components of natural and acquired immunityThe present study was designed to examine the effects of a sesquiterpene lactone isolated from Artemisia douglasiana Besser (dehydroleucodine) and a xanthanolide sesquiterpene isolated from Xanthium cavanillesii Schouw (xanthatin) on mast cell degranulation induced by substance P, neurotensin and neuromedin.Peritoneal mast cells from male adult Wistar rats were preincubated in the presence of test lactones dehydroleucodine (DhL) or xanthatin (Xt) and then challenged with the mast cell secretagogues Subtance P (SP), neurotensin (NT) and (NM). Concentration-response and kinetic studies of mast cell serotonin release evoked by SP, NT and NM, in both incubation solutions and remaining cells, were quantified measured by means of high performance liquid chromatography (HPLC) with electrochemical detection. The results were expressed as a serotonin release percentage. Evaluation of mast cell viability and morphology by light microscopy, were carried out. The viability of mast cells was determined by their ability to exclude trypan blue and the measurement of serotonin in the supernatan. For statistics, Type 1 variance (ANOVA-1) was performed, followed by Tukey-Kramer test. P0.05) and then no challenged with sesquiterpene lactones. Mast cell serotonin release effects caused by SP and NT were significantly reduced by dehydroleucodine and xanthatin in a dose-dependent manner. Serotonin release studies, together with morphological studies, showed the effectiveness of the lactones to stabilize mast cells. In all samples trypan blue tests showed >93% cell viability. These results were not caused by cytotoxic effects.The present research provides strong evidence in favour of the hypothesis that dehydroleucodine and xanthatin inhibit SP- and NT-induced serotonin release from peritoneal mast cells, acting thus as mast cell stabilizers. Dehydroleucodine and xanthatin may represent new pharmacological strategies in the treatment of neurogenic inflammation mediated by mast cell activation and may provide a new line of research in neuropathic pain therapy.