ABSTRACT
Objective To establish female and male bovine collagen-induced arthritis(CIA)models and compare the effects of gender differences on joint and extra-articular manifestations of the CIA model.Methods The CIA model was induced by injection of bovine type Ⅱ collagen and Freund's complete adjuvant into female and male SD rats.The general condition,arthritis index,foot swelling,serum proinflammatory factors and plasminogen activator inhibitor levels,spleen index,knee and ankle joint pathologies,right rear paw bone destruction,and pulmonary interstitial lesions were evaluated.Results The arthritis index of female CIA rats was significantly higher than that of male CIA rats on day 21 after initial immunization(P＜0.05),but no significant difference was found in the degree of foot swelling between the two groups at any time point(P＞0.05).Serum tumor necrosis factor α,interleukin-1β,and the spleen index of female CIA rats were significantly higher than those of male CIA rats(P＜0.05,P＜0.001).No significant difference was found in plasminogen activator inhibitor levels(P＞0.05).The scores of inflammatory cell infiltration and synovial hyperplasia in the knee and ankle pathologies of female CIA rats were significantly higher than those of male CIA rats(P＜0.05),and cartilage damage of the knee joint and bone damage of the right rear paw of female CIA rats were significantly higher than that of male rats(P＜0.05).Both male and female CIA rats showed pulmonary interstitial inflammatory cell infiltration and mild fibrosis,but the pulmonary interstitial lesions in females were more severe than those in males.Conclusions Female and male CIA models established in SD rats have arthritis and pulmonary interstitial lesions,but the lesion degree in female CIA rats is more serious.When using CIA models for RA-related research,attention should be focused on the effect of gender differences.