一种新的类风湿关节炎合并间质性肺病小鼠模型的建立与评价OA

Objective:To establish a mouse model of rheumatoid arthritis with interstitial lung disease(RA-ILD)in DBA/1 mice using Porphyromonas gingivalis(Pg)infection combined with collagen-induced arthritis(CIA),and to comprehensively evaluate pathological characteristics in joints,lungs,and serum.Methods:Forty DBA/1 mice were randomly divided into four groups,i.e.,Control,Pg infection(Pg),CIA,and Pg infection combined with CIA(Pg+CIA),with 10 mice in each group.Arthritis clinical symptoms were evaluated by recording arthritis incidence and clinical scores.Micro-CT scanning was used to assess knee joint pathology.Histopathological changes and collagen deposition in knee joints and lung tissues were analyzed using hematoxylin-eosin(HE)and Masson staining.Immunohistochemistry was performed to detect protein expression of α-smooth muscle actin(α-SMA),type Ⅰ collagen(Col Ⅰ),and fibronectin(FN)in lung tissues.Real-time quantitative polymerase chain reaction(Real-time PCR)was used to measure mRNA expression levels of α-SMA,Col Ⅰ,FN,tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),and IL-1β in lung tissues.Enzyme-linked immunosorbent assay(ELISA)was used to detect serum levels of Pg,cyclic citrullinated peptide(CCP),and immunoglobulin G(IgG).Results:Joint lesions:The CIA and Pg+CIA groups showed 100％arthritis incidence,with evident joint redness,swelling,and deformity.The number of affected limbs was 27 and 28,and clinical scores were 68 and 70,respectively.No obvious clinical symptoms were observed in the Pg group.Histopathological and imaging analyses showed severe joint lesions in the CIA and Pg+CIA groups,with significantly increased histopathological scores,bone mineral density,bone volume fraction,trabecular thickness,and trabecular number compared to the Control group(P＜0.01).No obvious joint pathology was observed in the Pg group.Lung lesions:The Pg+CIA group exhibited marked alveolar inflammation,interstitial inflammatory cell infiltration,and alveolar wall thickening,with pronounced blue staining of collagen fibers.Histopathological scores and collagen area ratios were significantly higher than those of the Control,Pg,and CIA groups(P＜0.05).Lung protein and mRNA expression levels of α-SMA,Col Ⅰ,and FN were markedly increased,and mRNA levels of IL-6,TNF-α,and IL-1β were significantly elevated compared to the Control group(P＜0.05).Serology:The Pg+CIA group showed significantly higher levels of CCP,Pg,and IgG compared with the Control,Pg,and CIA groups(P＜0.05).Conclusion:DBA/1 mice subjected to Pg infection combined with CIA exhibited pronounced symptoms and pathological features of RA-ILD,along with elevated serum anti-CCP antibody levels.This model represents a novel RA-ILD mouse model,providing a valuable experimental tool for investigating RA-ILD pathogenesis and developing new therapeutics,and serves as a basis for establishing anti-cyclic citrullinated peptide antibody(ACPA)-positive RA-ILD animal models.