Characteristics of polyarthritis in rabbits by hyperimmunization with attenuated Enterococcus faecalis

Area of Science:

• Immunology
• Rheumatology
• Microbiology

Background:

• Enterococcus faecalis (E. faecalis) is a common intestinal bacterium.
• Chronic polyarthritis is a debilitating joint disease with complex etiology.
• Developing reliable animal models is crucial for understanding and treating polyarthritis.

Purpose of the Study:

• To establish an animal model for chronic polyarthritis.
• To investigate the effects of hyperimmunization with E. faecalis.
• To characterize the induced inflammatory and immunological responses.

Main Methods:

• Rabbits were intravenously hyperimmunized with thimelosal (TMS)-treated E. faecalis.
• Joint swelling and fluid cultures were monitored.
• Histological examination assessed inflammatory and degenerative changes.
• Rheumatoid factor-like substance (RFLS) titers were measured.

Main Results:

• A high incidence of polyarthritis was observed, particularly affecting knee joints (41%).
• Histology revealed acute and chronic inflammatory changes, including pannus formation and cartilage destruction.
• RFLS titers exhibited biphasic peaks, indicating an immune response.
• E. faecalis was intermittently cultured from shoulder joint fluids.

Conclusions:

• Hyperimmunization with attenuated E. faecalis can induce a chronic polyarthritis model in rabbits.
• The model mimics key features of human rheumatoid arthritis, including joint inflammation and autoantibody production.
• This E. faecalis-induced polyarthritis model offers a valuable tool for studying disease pathogenesis and testing therapies.