Models in vivo and in vitro for the study of acute and chronic inflammatory activity: A comprehensive review.

Inflammatory conditions are among the principal causes of morbidity worldwide, and their treatment continues to be a challenge, given the restricted availability of effective and safe drugs. Thus, the identification of new compounds with biological activity that can be used for the treatment of inflammatory disorders is an essential field in medical and health research, in order to improve the health and quality of life of patients suffering from these diseases. Evaluation of the anti-inflammatory activity of drugs requires the implementation of models that accurately depict the biochemical and/or physiological responses that characterize human inflammation; for this reason, several in vitro and in vivo models have been developed, providing a platform for discovering novel or repurposed compounds. For this reason, in the present review we have selected twelve commonly used models for the evaluation of the anti-inflammatory effect, and extensively describes the difference between in vivo and in vitro models of inflammation, highlighting their advantages and limitations. On the other hand, the inflammatory mechanisms involved in them, the methods employed for their establishment, and the different parameters assessed to determine the anti-inflammatory activity of a given compound are extensively discussed. We expect to provide a comprehensive guide for the improved selection of a suitable model for the preclinical evaluation of plausible anti-inflammatory agents.

Activation of murine macrophages by membrane proteins from Tritrichomonas foetus grown on iron- and calcium-rich conditions.

Tritrichomonas foetus is a protozoan parasite that causes a venereal disease in cattle limiting reproduction by abortions and sterility. The immune response against this parasite is poorly understood. Since the iron and calcium ions are important regulators of the microenvironment of the urogenital tract in cattle, we decided to evaluate the role of these divalent cations on the antigenicity of membrane proteins of T. foetus on macrophage activation as one of the first inflammatory responses towards this pathogen. Colorimetric methods and ELISA were used to detect the nitric oxide and oxygen peroxide production and expression of cytokines in culture supernatant from macrophage incubated with membrane proteins from T. foetus cultured in iron- and calcium-rich conditions. qRT-PCR assays were used to evaluate the transcript expression of genes involved in the inflammatory response on the macrophages. The membrane proteins used for in vitro stimulation caused the up-regulation of the iNOS and NOX-2 genes as well as the generation of NO and H2 O2 in murine macrophages on a dependent way of the metal concentrations. Additionally, after stimulation, macrophages showed a considerable rise in pro-inflammatory cytokines and a downregulation of anti-inflammatory cytokines, as well as up-regulation in the transcription of the TLR4 and MyD88 genes. These data suggest that membrane proteins of T. foetus induced by iron and calcium can activate an inflammatory specific macrophage response via TLR4/MyD88 signalling pathway.

Exposure of Tritrichomonas foetus to sublethal doses of metronidazole induces a specific proinflammatory response in murine macrophages.

Tritrichomonas foetus is a flagellated parasite that primarily infects the reproductive tissues of livestock, causing bovine trichomoniasis. The cytoplasmic membrane of T. foetus contains various compounds that contribute to adherence, colonization, and pathogenicity. Metronidazole (MTZ) is the main treatment for trichomoniasis, but the emergence of drug-resistant strains is a concern due to improper use and dosing. T. foetus infection induces inflammation, and macrophages are key players in the immune response. However, our understanding of the host's immune response to T. foetus is limited, and the specific mechanisms underlying these responses are not well understood. This study aimed to investigate the impact of T. foetus surface proteins from trophozoites cultured under different sublethal MTZ conditions (MTZ-treated T. foetus MPs) on macrophage activation. By analyzing cytokine levels and gene expression in murine macrophages, we demonstrated that MTZ-treated T. foetus MPs induce a specific proinflammatory response. MTZ-treated T. foetus MPs-exposed macrophages exhibited a higher NO and H2 O2 production and overexpression of iNOS and NOX-2 genes in comparison to untreated T. foetus. Additionally, MTZ-treated T. foetus MPs triggered a significant induction of the proinflammatory cytokines IL-1ß, IL-6, TNF-α, and IFN-γ, as well as the overexpression of the TLR4, MyD88, and NF-κB genes on murine macrophages. The study aimed to unravel the immunological response and potential proinflammatory pathways involved in T. foetus infection and MTZ stress. Understanding the immune responses and mechanisms through which T. foetus surface proteins activate macrophages can contribute to the development of new therapeutic strategies for controlling bovine trichomoniasis.

In Vitro Activation of Macrophages by an MHC Class II-restricted Trichomonas Vaginalis TvZIP8-derived Synthetic Peptide.

BACKGROUND: Macrophages play an important role in the inflammatory response towards pathogens and their effector functions depend on the mode of activation which is mediated by recognition of pathogen-associated molecular patterns, as peptides. Trichomonas vaginalis provokes an inflammatory response in the host in which macrophages are the first line of defense. This study aimed to analyze the effect of a specific peptide derived from the transporter TvZIP8 of T. vaginalis on the activation of macrophages. METHODS: An in silico approach based on computational prediction of epitopes was applied to detect potential murine MHC class II-restricted peptides from TvZIP8 that can activate macrophages and the immunomodulatory activity was evaluated by in vitro stimulation of murine macrophages. RESULTS: Based on binding scores, one peptide denominated TvZIP8-pep was selected for further analysis. In vitro stimulation with synthetic TvZIP8-pep triggered on murine macrophages the NO and H2O2 production and an overexpression of iNOS and NOX-2 genes. Also, a significant increase of pro-inflammatory cytokines: IL-1ß, IL-6, and TNF-α, as well as, overexpression of the TLR4, MyD88, and NF-κB genes and NF-κB activation were observed on macrophages after stimulation with TvZIP8-pep in vitro. Moreover, higher levels of IFN-γ were detected in co-cultures using CD4 + T cells with TvZIP8-pep-stimulated macrophages. CONCLUSION: These results support the potential of TvZIP8 as a promising antigen to stimulates a specific macrophage response against T. vaginalis, but further analyses are required to evaluate their possible potential as a novel antigen for immunodiagnosis and/or vaccine against trichomoniasis.

Anti-inflammatory and antinociceptive effects of an ethanol extract from Senna septemtrionalis.

Senna septemtrionalis (Viv.) H.S. Irwin & Barneby (Fabaceae) is a medicinal plant used as a folk remedy for inflammation and pain. The objective of this study was to evaluate the anti-inflammatory and antinociceptive actions of an ethanol extract of Senna septemtrionalis aerial parts (SSE). The in vitro anti-inflammatory effects of SSE were assessed using LPS-stimulated macrophages and the subsequent quantification of the levels of cytokines (IL-6, IL-1ß, and TNF-α) with ELISA kits, nitric oxide (NO), and hydrogen peroxide (H2O2). The in vivo anti-inflammatory actions of SSE were evaluated with the TPA-induced ear oedema test and the carrageenan-induced paw oedema test. The antinociceptive actions of SSE (10-200 mg/kg p.o.) were assessed using three models: two chemical assays (formalin-induced orofacial pain and acetic acid-induced visceral pain) and one thermal assay (hot plate). SSE showed in vitro anti-inflammatory actions with IC50 values calculated as follows: 163.3 µg/ml (IL-6), 154.7 µg/ml (H2O2) and > 200 µg/ml (IL-1ß, TNF-α, and NO). SSE showed also in vivo anti-inflammatory actions in the TPA test (40% of inhibition of ear oedema) and the carrageenan test (ED50 = 137.8 mg/kg p.o.). SSE induced antinociceptive activity in the formalin orofacial pain test (ED50 = 80.1 mg/kg) and the acetic acid-induced writhing test (ED50 = 110 mg/kg). SSE showed no antinociceptive actions in the hot plate assay. The pre-treatment with glibenclamide abolished the antinociceptive action shown by SSE alone. Overall, SSE exerted in vitro and in vivo anti-inflammatory actions, and in vivo antinociceptive effects by the possible involvement of ATP-sensitive K + channels.