Oral administration of type II collagen suppresses non-specifically induced chronic arthritis in rats

The present study was designed to investigate the efficacy of oral administration of type II collagen (CII) on non-specifically induced chronic arthritis in rats, induced by intra-articular injection of a mineral oil, squalene. When CII was fed before injection of squalene, no chronic arthritis developed. Feeding CII after the induction of arthritis was also effective in suppressing the progression of chronic joint inflammation. Lymph node cells from rats with squalene-induced arthritis failed to show proliferative responses to CII. In rats fed and primed with CII, there was a decrease in proliferative responses to CII. Arthritis induced by the mineral oil was markedly suppressed by the spleen cells from animals fed CII. These results indicate that non-specifically induced arthritis may be downregulated by the oral administration of CII and that the downregulation of joint inflammation may be due to the generation of CII-specific regulatory T cells that react to CII abundance in cartilage.