Objective To investigate the effect of photodynamic therapy ( PDT) on histopathologic changes and proliferating cell nuclear antigen ( PCNA) expression in the animal model of rheumatoid arthritis ( RA). 目的观察光动力疗法对类风湿性关节炎模型病理及增殖细胞核抗原(proliferatingcellnuclearantigen,PCNA)表达的影响。