ObjectiveTo investigate the protective effect of synthetic fibers with tourmaline on collagen-induced arthritis in rats. MethodsWistar rats were randomly divided into three groups, namely, the control (n=5), model (n=12), and protected (n=13) groups. Rheumatoid arthritis (RA) was induced by immunization with typeⅡcollagen in Freund’s incomplete adjuvant in model group and protected group. Animals in model group were protected by conventional synthetic fibers and those in protected group were protected by the synthetic fibers with tourmaline. The protective effects were evaluated by comparing the appearance, volume (water drainage method), and pathological changes of rat paws in different groups. ResultsRats in model group exhibited more severe arthrocele than those in the protected group, and there was even arthrentasis. Histological analysis showed that the model group had more severe pathological changes in both left and right hindpaws than the protected group. Since the second week, the mean volumes of left hindpaws of protected group were smaller than those of model group, with the differences at week 2, 6, 8, 10, and 12 being significantly different (P<0.05). The protected group also had a lower incidence of RA than the model group. ConclusionSynthetic fibers with tourmaline have protective effect against collagen Ⅱ-induced arthritis in rats.