Efeito anti-inflamatório e imunomodulador de componentes de ascaris suum em artrite experimental

Abstract

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease with multifactorial etiopathogenesis, involving genetic, immunological and environmental mechanisms, whose diagnosis and delayed treatment have a negative influence on the prevalence and severity of the disease. Therefore, patients residing in low-income countries should show increased morbidity and / or mortality from these diseases. Interestingly, the evolution seems to be similar, if not less severe, to that found in populations with better socioeconomic indexes. The hygienic hypothesis suggests an inverse relationship between the global distribution of autoimmune diseases and parasitic infections, where helminths tend to stimulate the development of Th2 responses and suppress Th-1 and Th-17 responses. The aim of this study was to isolate components in Ascaris suum extract and characterize its anti-inflammatory mechanism in experimental arthritis models. Ascaris suum crude extract was separated into fractions > 30 and <30 kDa. Four smaller fractions (1-4) were obtained, in the fraction <30 kDa, by native electrophoresis. In fraction 1, the ABA-1 protein was identified by mass spectrometry and after protein digestion with trypsin, seven peptides were isolated (Aba-AG). The genomic sequence of the Aba-B and Aba-F peptides was inserted into a commercial plasmid (VR2 -001-TOPO ™). Plasmids were cloned and expanded in E. coli and extraction of plasmid DNA was performed by commercial kit (Qiagen ™). Male Swiss mice received crude extract of A. suum (1mg), > 30kDa, <30kDa (50ng) or fractions 1, 2, 3 and 4 (1μL), diluted in sterile saline (200 μL), p.o., 30min before of the injection of Zy (0.1mg) i.a. Hypernociception was evaluated by the electronic von Frey and the cellular influx was evaluated in the joint fluid 6h or seven days after zymosan i.a. Swiss and Balb/c male mice, submitted to ZyA and AIA, respectively, received recombinant plasmids of Aba-B or Aba-F (50μg/30μL) at the back of each hind leg. The cell influx was evaluated 6h or seven days (ZyA) and 7h or 14 days (AIA) after the i.a stimulus. Cytokines were evaluated in the synovial fluid. Synovitis and joint damage were evaluated by H&E and safranin O, respectively, and mast cell by toluidine blue. Levels of cytokines (CXCL-1, IL-1β, IFN-γ, IL- 5, IL-6 and IL-10) were assessed by ELISA and the expression of iNOS, CD11b, F4/80 and CD206 by immunohistochemistry. The administration of fractions <30 kDa, 1 and 4 reduced hypernociception and acute and chronic cellular influx in the ZyA model. Transfection with both plasmids, Aba-B or F, significantly reduced the influx of cells in both the zymosan and acute and chronic mBSA arthritis models. Reduction of synovitis, mast cell numbers, joint damage and iNOS expression were observed. Levels of CXCL1, IFN-γ, IL-1β and IL-6 were reduced. However, IL-10 levels did not increase. Surprisingly, IL-5 levels were significantly reduced after plasmid injection. Plasmids increased the expression of M2 macrophages in the synovium. A qPCR analysis showed the expression of peptides in the thigh muscles of mice that received the plasmids. This is the first demonstration that peptide sequences derived from A. suum promote anti-inflammatory activity in arthritis models, and that it is associated with reduced release of inflammatory cytokines. Peptides promoted a change in the differentiation of macrophages in the synovial membrane at the same time, decreasing the release of IL-5. Despite the complex modulating mechanisms of helminths of inflammation, the data still support a protective effect of helminth products in chronic arthritis.