RESUMO
SCOPE: In the attempt to develop new therapeutic treatments for colitis, fractions containing phenolic compound isolate (Phi) and phenolic reduced-flaxseed protein hydrolysate (phr-FPH) from flaxseed are evaluated for their effects on the in vitro production of pro-inflammatory mediators and on the course of experimental colitis. METHODS AND RESULTS: The anti-inflammatory effects of Phi and phr-FPH from flaxseeds are studied in RAW264.7 cells and in trinitrobenzene sulphonic acid (TNBS) colitis model. It is observed that the incubation with Phi or phr-FPH result in lower levels of tumor necrosis factor α and nitric oxide in macrophages stimulated with bacterial lipopolysaccharide + interferon-γ. Prophylactic and therapeutic treatments with Phi and phr-FPH, respectively, greatly contribute to the prevention of weight loss and colon inflammation in colitic BALB/c mice. T cell proliferation, expansion of TH1 and TH17 cells, and pro-inflammatory cytokines are lower, whereas Treg cells are higher in spleen cell cultures from Phi-treated mice. In addition, therapeutic phr-FPH treatment is able to reduce the expansion of TH17 in splenic cell cultures. CONCLUSION: The consumption of phenolic and protein compounds extracted from flaxseeds has a protective effect on TNBS-induced colitis, and may be useful in the control of other inflammatory disorders.
Assuntos
Colite/tratamento farmacológico , Linho/química , Hidrolisados de Proteína/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Colite/induzido quimicamente , Colite/etiologia , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Mediadores da Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Fenóis/farmacologia , Células RAW 264.7 , Células Th17/efeitos dos fármacos , Ácido Trinitrobenzenossulfônico/toxicidadeRESUMO
INTRODUCTION: In addition to conventional therapies, several new strategies have been proposed for modulating autoimmune diseases, including the adoptive transfer of immunological cells. In this context, dendritic cells (DCs) appear to be one of the most promising treatments for autoimmune disorders. The present study aimed to evaluate the effects of adoptive transfer of DCs obtained from both naïve and ovalbumin (OVA)-tolerant mice on the severity of TNBS induced colitis and analyze the eventual protective mechanisms. METHODS AND RESULTS: To induce oral tolerance, BALB/c mice were fed 4mg/mL OVA solution for seven consecutive days. Spleen DCs were isolated from tolerant (tDC) and naïve (nDC) mice, and then adoptively transferred to syngeneic mice. Three days later, colitis was induced in DC treated mice by intrarectal instillation of 100µg2,4,6-trinitrobenzenesulfonic acid (TNBS) dissolved in 50% ethanol. Control subjects received only intrarectal instillation of either TNBS solution or a vehicle. Five days later, mice from all groups were euthanized and examined for physiological and immunological parameters. Regarding the phenotype, we observed that the frequencies of CD11+ MHC II+ and CD11+ MHCII+ CD86+ cells were significantly lower in DCs isolated from tolerant mice than in those from naive mice. However, pretreatment with both types of DCs was able to significantly reduce clinical signs of colitis such as diarrhea, rectal prolapse, bleeding, and cachexia, although only treatment with tDCs was able to prevent weight loss from instillation of TNBS. In vitro proliferation of spleen cells from mice treated with either type of DCs was significantly lower than that observed in splenic cell cultures of naïve mice. Although no significant difference was observed in the frequencies of Treg cells in the experimental groups, the frequency of Th17+CD4+cellsand the secretion of IL-17 were more reduced in the cultures of spleen cells from mice treated with either type of DCs. The levels of IL-9 and IFN-γ were lower in supernatants of cells from mice treated with nDCs. CONCLUSION: The results allow us to conclude that the adoptive transfer of cells expressing CD11c is able to reduce the clinical and immunological signs of drug-induced colitis. Adoptive transfer of CD11c+DC isolated from both naive and tolerant mice altered the proliferative and T cell responses. To the best of our knowledge, there is no previously published data showing the protective effects of DCs from naïve or tolerant mice in the treatment of colitis.
Assuntos
Terapia Baseada em Transplante de Células e Tecidos , Colite/terapia , Células Dendríticas/transplante , Tolerância Imunológica , Transferência Adotiva/métodos , Animais , Antígeno B7-2/imunologia , Antígeno CD11c/imunologia , Colite/induzido quimicamente , Colite/imunologia , Células Dendríticas/citologia , Células Dendríticas/imunologia , Humanos , Camundongos , Ovalbumina/efeitos adversos , Ovalbumina/imunologia , Baço/citologia , Baço/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Ácido Trinitrobenzenossulfônico/toxicidadeRESUMO
INTRODUCTION: Literature data have shown that the consumption of dietary proteins may cause modulatory effects on the host immune system, process denominated oral tolerance by bystander suppression. It has been shown that the bystander suppression induced by dietary proteins can improve inflammatory diseases such as experimental arthritis. Here, we evaluated the effects of oral tolerance induced by ingestion of ovalbumin (OVA) on TNBS-induced colitis in mice, an experimental model for human Crohn's disease. METHODS AND RESULTS: Colitis was induced in BALB/c mice by instilling a single dose of TNBS (100 mg/kg) in ethanol into the colon. Tolerized mice received OVA (4mg/mL) dissolved in the drinking water for seven consecutive days, prior to or concomitantly with the intrarectal instillation. Control groups received protein-free water and ethanol by intrarectal route. We observed that either the prior or concomitant induction of oral tolerance were able to reduce the severity of colitis as noted by recovery of body weight gain, improvement of clinical signs and reduction of histological abnormalities. The in vitro proliferation of spleen cells from tolerant colitic mice was lower than that of control mice, the same as the frequencies of CD4+ T cells secreting IL-17 and IFN-γ. The frequencies of regulatory T cells and T cells secreting IL-10 have increased significantly in mice orally treated with OVA. The levels of inflammatory cytokines (IL-17A, TNF-α, IL-6 and IFN-γ) were lower in supernatants of cells from tolerant colitic mice, whereas IL-10 levels were higher. CONCLUSION: Our data show that the modulation of immune response induced by oral tolerance reduces the severity of experimental colitis. Such modulation may be partially attributed to the increase of Treg cells and reduction of pro-inflammatory cytokines in peripheral lymphoid organs of tolerant mice by bystander suppression.