Beyond Inflammation: How Advanced Arthritis Models Help Us Stay Active and Pain-Free This Summer

by Katie Dineen, B.S. Biology, Business Development Manager, Preclinical Research Services

Why Joint Health Demands More Attention in Summer

As the sun coaxes us outdoors, physical activity naturally increases—morning runs, tennis matches, gardening, and evening walks all become part of daily life again. But for the 1 in 4 adults living with arthritis, this seasonal upswing in movement often comes with an unwelcome rise in joint pain and stiffness.

Traditionally, arthritis treatment has zeroed in on controlling inflammation—reducing swelling, immune infiltration, and joint degradation. But what happens when the pain persists even in the absence of measurable inflammation?

This lingering pain is more than anecdotal—it’s a clinical puzzle. And a pivotal study from 2019 may offer the scientific explanation we’ve been waiting for.

The 2019 Study That Shifted the RA Pain Paradigm

A 2019 preclinical study, published in the Journal of Experimental Medicine, used Collagen Antibody-Induced Arthritis (CAIA) models to probe the less-visible side of rheumatoid arthritis: pain that exists without inflammation.

Researchers discovered that autoantibodies binding to cartilage, specifically to collagen type II and COMP (cartilage oligomeric matrix protein)—can form immune complexes that directly stimulate pain-sensing neurons.

These immune complexes were shown to activate peripheral nociceptors via Fc gamma receptors (FcγRs) on sensory neurons, triggering mechanical hypersensitivity—a model for chronic arthritis pain—even in the absence of histological or molecular inflammation.

In mice genetically deficient in these neuronal receptors, the same immune complexes failed to provoke pain-like behavior. The takeaway? Pain in RA may stem from direct immune-neural interactions—not just inflamed joints.

This not only redefines how we understand arthritis pain, it also redefines how we should study it.

Why CAIA and CIA Models Matter

At MLM Medical Labs, we specialize in two robust, complementary preclinical models that help researchers capture the full complexity of RA pathophysiology:

CIA (Collagen-Induced Arthritis)

■ A chronic autoimmune model that closely mirrors the progression and immunological triggers of human RA.

■ Ideal for studying adaptive immune responses, synovial inflammation, and disease-modifying anti-rheumatic drugs (DMARDs).

CAIA (Collagen Antibody-Induced Arthritis)

■ A rapid-onset, antibody-mediated model that bypasses the need for adaptive immunity.

■ Excellent for evaluating therapeutics targeting the effector phase, and, as shown in the 2019 study, for exploring pain mechanisms driven by immune complexes.

Together, these models offer a holistic approach—helping researchers evaluate candidate therapies across both inflammatory and non-inflammatory pain pathways.

Better Models = Better Outcomes

Choosing the right preclinical model isn’t just a protocol decision—it can make the difference between a missed signal and a breakthrough.

At MLM Medical Labs, our CAIA and CIA models:

■ Offer high translational value by reflecting key mechanisms of human disease.

■ Enable the discovery of pain pathways beyond inflammation, a feature often overlooked in conventional models.

■ Support accelerated timelines through reproducibility and rapid onset, facilitating faster go/no-go decisions in early-stage research.

With established protocols, expert execution, and scientific partnership, your studies would be both reliable and insight-driven.

Keeping People Moving—One Study at a Time

In the heart of summer, when movement is a must, the need for joint-friendly innovations becomes clearer. The science behind RA pain is evolving, and so should our models. By investing in predictive platforms like CAIA and CIA, we’re not just improving therapeutics—we’re improving lives.

Whether you’re developing anti-inflammatories, or biologics that modulate the immune system, MLM’s arthritis models are designed to help you move faster—and more meaningfully—toward success.

Interested in learning more about our arthritis models?

We’d love to support your next preclinical arthritis study with models that move science—and patients—forward.

👉 Contact us here

👉 Or explore our arthritis models page