APH02174

Collagen-induced arthritis (CIA) is an autoimmune murine model of rheumatoid arthritis in which immunization with type II collagen (CII) emulsified in an adjuvant induces a T cell- and autoantibody-driven inflammatory arthritis characterized by synovial hyperplasia, immune cell infiltration, and joint destruction. The model typically relies on genetically susceptible mouse strains (e. g. , DBA/1) and reproduces key features of human rheumatoid arthritis, including anti-collagen immune responses and progressive joint inflammation. Disease onset generally occurs within ~3-4 weeks after immunization, depending on antigen/adjuvant combinations and protocol variation. The immunopathology is driven by adaptive immune activation against CII, leading to systemic and local joint inflammation mediated by pro-inflammatory cytokines and effector immune cells, making CIA a standard preclinical platform for evaluating immunomodulatory and anti-arthritic interventions.

Imiquimod (IMQ)-induced psoriasiform dermatitis is a widely used murine model in which topical application of IMQ, a Toll-like receptor 7 (TLR7) agonist, triggers innate immune activation in the skin and induces a psoriasis-like inflammatory cascade characterized by epidermal hyperplasia, immune cell infiltration, and cytokine production dominated by the IL-23/IL-17 axis. This inflammatory response is mediated through activation of dendritic cells and downstream induction of IL-23, IL-17A, IL-22, and related pro-inflammatory mediators, recapitulating key features of human plaque psoriasis and enabling mechanistic and therapeutic studies. The model is commonly induced using Aldara (5% IMQ cream) applied topically to murine skin, resulting in rapid onset of erythema, scaling, and thickening that can be quantified as disease severity indices and validated histologically.

Cotton pellet granuloma is a classical in vivo chronic inflammation model used to evaluate the anti-inflammatory potential of test substances by measuring their ability to inhibit granuloma tissue formation around an implanted foreign body (cotton pellet) in rodents. The method is based on the biological response to a sterile implanted material, which induces proliferative phase inflammation characterized by fibroblast proliferation and collagen-rich granuloma formation, and the final readout reflects the extent of chronic inflammatory tissue growth surrounding the pellet. In multiple preclinical pharmacological evaluations, inhibition of cotton pellet-induced granuloma formation has been used as an indicator of anti-inflammatory activity in both synthetic and natural product screening contexts.

Carrageenan-induced paw edema is an acute inflammation model in which intraplantar injection of carrageenan induces localized inflammatory swelling characterized by vascular permeability, leukocyte infiltration, and production of inflammatory mediators such as prostaglandins and cytokines, making it widely used to evaluate anti-inflammatory agents in vivo. The resulting paw volume or thickness increase is quantified over time as a direct readout of inflammatory intensity and drug efficacy, typically reflecting cyclooxygenase-mediated prostaglandin-driven edema formation and immune cell recruitment in peripheral tissue[20].

The TPA (12-O-tetradecanoylphorbol-13-acetate) and croton oil-induced mouse ear edema model is a well-established acute cutaneous inflammation system used to evaluate topical anti-inflammatory activity by measuring edema formation, neutrophil infiltration, vascular permeability, and cytokine-mediated skin responses in vivo. The inflammatory response is triggered by topical application of phorbol esters (TPA) or croton oil constituents, leading to rapid activation of protein kinase C signaling, leukocyte recruitment, and increased vascular permeability, which can be quantified by ear thickness, weight, dye extravasation, and biochemical markers such as myeloperoxidase (MPO) activity and pro-inflammatory mediators in ear tissue homogenates. This model is widely used for screening anti-inflammatory agents, where reductions in edema and inflammatory biomarkers reflect suppression of acute dermal inflammation and immune cell infiltration. Histological evaluation typically confirms epidermal

Contact hypersensitivity (CHS) dermatitis is a T cell-mediated delayed-type (Type IV) immune reaction in which low-molecular-weight haptens applied to the skin bind host proteins to form complete antigens, triggering sensitization followed by a secondary inflammatory response upon re-exposure (elicitation phase), which is commonly quantified by ear swelling as a readout of skin inflammation in murine models. This model is widely used to study allergic contact dermatitis because it is antigen-specific, reproducible, and reflects key immunological events including dendritic cell activation, T cell priming in draining lymph nodes, and effector T cell-driven tissue inflammation. DNFB- and oxazolone-induced CHS models are standard systems for evaluating both acute and chronic T cell-dependent skin inflammation and for testing immunomodulatory interventions.

The NLRP3 inflammasome is a cytosolic innate immune signaling platform that integrates priming signals and danger-signal activation to promote caspase-1 activation, maturation of IL-1β and IL-18, and gasdermin D-mediated pyroptotic cell death. The core experimental logic is to determine whether inflammatory disease phenotypes are driven by increased NLRP3 expression, ASC-containing inflammasome assembly, caspase-1 cleavage, GSDMD cleavage, and extracellular release of IL-1β/IL-18 rather than by nonspecific cell injury alone. The pathway is strongly linked to inflammation-related disease phenotypes because monosodium urate crystals activate NALP3/NLRP3 inflammasome signaling in gout-like crystal inflammation, cholesterol crystals activate NLRP3 inflammasomes in atherogenesis models, and DSS-induced intestinal inflammation has been reported to involve NLRP3 inflammasome activity. However, experimental colitis studies also show context-dependent protective effects of NLRP3 inflammasome co