Applicability and implementation of the collagen-induced arthritis mouse model, including protocols (Review)

Abstract

Animal models of rheumatoid arthritis (RA) are essential for studying the pathogenesis of RA in vivo and determining the efficacy of anti-RA drugs. During the past decades, numerous rodent models of arthritis have been evaluated as potential models and the modeling methods are relatively well-developed. Among these models, the collagen-induced arthritis (CIA) mouse model is the first choice and the most widely used because it may be generated rapidly and inexpensively and is relatively similar in pathogenesis to human RA. To date, there have been numerous classic studies and reviews discussing related pathogeneses and modeling methods. Based on this knowledge, combined with the latest convenient and effective methods for CIA model construction, the present review aims to introduce the model to beginners and clarify important details regarding its use. Information on the origin and pathogenesis of the CIA model, the protocol for establishing it, the rate of successful arthritis induction and the methods used to evaluate the severity of arthritis are briefly summarized. With this information, it is expected that researchers who have recently entered the field or are not familiar with this information will be able to start quickly, avoid unnecessary errors and obtain reliable results.

Keywords: applicability; collagen-induced arthritis; mouse model; protocol; rheumatoid arthritis.

Figure 1

Flowchart for the generation of collagen-induced arthritis model mice. CII, collagen type II; CFA, complete Freund's adjuvant; IFA, incomplete Freund's adjuvant.

Figure 2

Images of (A) the DBA/1 mouse model of CIA and (B) the C57BL/6 mouse model of CIA. CIA, collagen-induced arthritis.

Figure 3

Representative images of hind paws for different clinical scores in mice with collagen-induced arthritis. The upper and lower panels represent the right and left hind paws of different mice, respectively. (A) Normal hind paw (clinical score 0). (B) Erythema and mild swelling confined to the tarsals, ankle joint or paw, with mild swelling in a single limb (clinical score 1). (C) Erythema and mild swelling extending from the ankle to the tarsals or erythema and mild swelling of more than one toe (clinical score 2). (D) Erythema and moderate swelling extending from the ankle to the metatarsal joints, or swelling and obvious erythema of the entire paw (clinical score 3). (E) Erythema and severe swelling of the whole paw, including the ankle, foot and digits; ankylosis of the limb; and dysfunction (clinical score 4).

Figure 4

Comparison of the spleens of normal mice and mice with CIA. (A) Representative images of spleens on day 31. The spleens of CIA mice were significantly larger than those of normal mice and the color of the spleen was dark red. (B) Immunohistochemical images of spleen sections. Mouse spleens were fixed in 4% formalin for 24 h. Histological analysis of the spleens was performed by staining 5-mm sections of paraffin-embedded tissues with H&E (magnification, x40, 100, 200 and 400 as indicated). (C) Representative images of spleens of asymptomatic model animals and controls; in the absence of arthritis symptoms in CIA mice, the spleens of CIA mice were still significantly larger than those of normal mice. (D) Statistical analysis of spleen coefficients in CIA mice (DBA/1 background) and normal mice (n=10 for each group). CIA, collagen-induced arthritis.

Figure 5

(A) Histology images of the normal group and the arthritis group reveal the main histological structure of the knee joint. Mouse joints were dissected and cleaned, and the samples were fixed in paraformaldehyde for one week prior to being decalcified for 1 month. When the bone became soft, the joints were embedded in paraffin for sectioning. The 5-mm sections were then stained with H&E for histopathological examination. In the arthritis group, typical cartilage and bone damage (arrow 1), synovial lining hyperplasia (arrow 2) and infiltration of inflammatory cells (arrow 3) were observed (magnification, x200). (B) Representative radiographs of the effects in the normal group and the arthritis group. Joint damage is visible at 31 days after arthritis induction, while normal joints were complete and exhibited no evidence of bone destruction. The joint space was clear and smooth. The joints of the mice with CIA displayed narrow spaces and diffuse soft tissue swelling. The ankle and toe joint spaces were hazy and narrow, and the bone displayed cystic changes and signs of apparent erosion and degradation. CIA, collagen-induced arthritis.