Modeling Principle

The Lewis Rat Avridine Arthritis Model is a classic SCI gold-standard induced animal model in the fields of experimental autoimmune arthritis mechanism research, rheumatoid arthritis (RA) pathological simulation, systemic autoimmune inflammatory response, and preclinical efficacy evaluation of anti-rheumatic drugs. Based on highly autoimmune-sensitive Lewis rats, the model breaks the body’s autoimmune tolerance and systematically activates systemic innate and adaptive immune pathways through subcutaneous injection of Avridine (diaminoacridine bromide) adjuvant at the tail base, stably inducing symmetrical, polyarticular and progressive limb arthritis lesions, which highly recapitulates the core pathological and clinical phenotypes of human rheumatoid arthritis. As a potent non-specific immune adjuvant, Avridine can efficiently stimulate persistent systemic autoimmune inflammatory responses, triggering abnormal synovial hyperplasia, extensive inflammatory cell infiltration, articular pannus neogenesis, degenerative cartilage damage and progressive bone erosion, completely reproducing the full-temporal pathological process of clinical RA from latent immune activation and acute inflammatory outbreak to chronic persistent inflammation and osseous structural destruction. Compared with collagen-induced and complete Freund’s adjuvant-induced arthritis models, this model has the core advantages of short modeling cycle, 100% modeling rate, uniform inflammatory phenotype, stable systemic immune response and extremely low individual data dispersion. Female Lewis rats exhibit higher pathogenic sensitivity and more typical inflammatory symptoms with highly consistent pathological characteristics with clinical autoimmune arthritis. The experimental paradigm fully complies with the specifications of high-impact SCI journals in rheumatology, osteoarticular pharmacology and translational medicine, and can be directly applied to National Natural Science Foundation projects, postgraduate research proposals and dissertations, serving as a standardized mainstream model for basic mechanism verification of autoimmune arthritis and screening of novel anti-inflammatory drugs.

Modeling Success Criteria

Quantitative Clinical Phenotype and Physical Sign Criteria

Unified model evaluation is completed at the inflammatory peak of 21 d after modeling, and there are significant statistical differences between the model group, blank group and vehicle control group: 1. Joint physical signs: rats in the model group present symmetrical redness, swelling, bulging and increased skin temperature in bilateral forelimb and hindlimb joints with deformed joint contours, showing typical polyarticular inflammatory phenotypes; 2. Behavioral performance: rats exhibit arthritis dysfunction characteristics including uneven limb weight bearing, claudication, decreased activity, curling and hypoactivity, pain sensitivity and limited limb flexion and extension; 3. Quantitative scoring: the clinical arthritis score, joint swelling degree and joint skin temperature of the model group are significantly higher than those of the control groups with statistically significant inter-group differences, while there is no significant difference between the vehicle control group and blank group, eliminating solvent and puncture interference; 4. Disease course stability: no unilateral occasional lesions, spontaneous inflammatory remission or sudden death, with continuous and stable inflammatory progression and no invalid model individuals. The Avridine-induced autoimmune arthritis model is successfully established when all the above physical and behavioral indicators reach the standard.

Histomorphometric Gold-Standard Indexes

Gold-standard histopathological evaluation of joint synovium and osteochondral tissues: the model group shows significant proliferation and thickening of synovial tissue, disordered synovial hierarchical structure, continuous infiltration of a large number of neutrophils, macrophages and lymphocytes, and massive intra-articular inflammatory exudation; synovial angiogenesis is significantly increased with pannus invading the joint space and eroding the superficial cartilage structure; a large amount of cartilage matrix is lost with thinning and disordered arrangement of cartilage layer and typical degenerative lesions; cortical bone presents osseous damage such as bone resorption, trabecular disorder and local bone erosion. The blank group and vehicle control group have complete synovial structure, clear layers, and intact cartilage and bone tissue without obvious inflammatory infiltration. Core histomorphometric indexes: the synovial hyperplasia thickness, inflammatory infiltration area ratio, angiogenesis number, cartilage damage score and bone erosion degree of the model group are significantly higher than those of the control groups. The pathological phenotype is completely consistent with the characteristics of clinical autoimmune rheumatoid arthritis, meeting the SCI gold standard for academic credibility.

Academic Evidence for Model Validity

The core academic validity basis of this model is as follows: Avridine adjuvant specifically breaks autoimmune tolerance in Lewis rats and continuously activates the classic NF-κB/TNF-α/IL-6 autoimmune inflammatory pathways, inducing systemic immune disorders and accurately recapitulating the core pathological mechanism of clinical rheumatoid arthritis: immune tolerance imbalance-systemic inflammatory activation-symmetrical multi-joint damage-progressive osteochondral destruction. This model has a clear modeling mechanism, stable disease onset sequence, extremely high phenotypic homogeneity and industry-recognized excellent experimental reproducibility, which can accurately quantify and evaluate the inhibitory and repair efficacy of various interventions on autoimmune inflammation, synovial hyperplasia, pannus formation and osteochondral damage, serving as an authoritative SCI gold-standard model for autoimmune arthritis mechanism research and preclinical screening of anti-rheumatic drugs.

Model Advantages

The Lewis Rat Avridine Arthritis Model is a high-impact SCI mainstream gold-standard model in the fields of autoimmune arthritis mechanism, systemic immune disorder regulation, pathological synovial hyperplasia, osteochondral damage and preclinical evaluation of new anti-rheumatic drugs. Relying on the natural high autoimmune sensitivity of Lewis rats, it achieves a 100% modeling success rate, highly uniform inflammatory phenotype and minimal individual differences. It has simple modeling operation, controllable cycle, moderate cost, extremely low animal mortality and low ethical risks. It can stably simulate the complete RA pathological chain of immune tolerance imbalance-systemic inflammation activation-symmetrical multi-joint injury-chronic osseous destruction, with a pathological phenotype far more consistent with clinical rheumatoid arthritis than ordinary adjuvant models. It has clear inflammatory sequence, stable peak value, low data dispersion and significant inter-group comparison differences, with highly credible experimental conclusions and excellent reproducibility. It adapts to multi-dimensional closed-loop verification including in vivo dynamic observation, histopathology, bone microstructure and molecular pathways. The experimental data is highly recognized and easily accepted by authoritative SCI journals in rheumatology and immunology, translational pharmacology and osteoarticular medicine, fully adapting to the high-level scientific research system of National Natural Science Foundation projects, fund application, research proposals and postgraduate dissertations.

Research Applications

This model is mainly used to systematically elucidate the core molecular mechanisms of Avridine-mediated immune tolerance imbalance, systemic autoimmune inflammatory cascade activation, pathological synovial hyperplasia, pannus formation and osteochondral erosion. It accurately evaluates the anti-inflammatory, analgesic, joint protective and immune regulatory efficacy of traditional Chinese medicine compounds, natural active ingredients, chemically synthesized drugs, targeted preparations and biomaterials on autoimmune arthritis. It verifies the linkage regulation mechanism of inflammation-immune disorder-bone metabolism imbalance and explores novel immune intervention targets and signaling pathways for rheumatoid arthritis, optimizing early intervention and long-term treatment schemes for autoimmune inflammation. It is widely applied in full scientific research scenarios including basic mechanism research of rheumatoid arthritis, preclinical efficacy screening of new anti-rheumatic drugs, translational medicine research of rheumatology and immunology, fund project application, research proposal writing and high-impact SCI paper publication, serving as an irreplaceable standardized SCI gold-standard model in the field of autoimmune arthritis research.

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