Flow Cytometry Analysed the Effect of Synovial Fluids from Rheumatoid Arthritis on Neutrophil Apoptosis

Objective To investigate neutrophil apoptosis in the presence of synovial fluids(SF) from patients with rheumatoid arthritis(RA)and osteoarthritis(OA).Methods Neutrophil apoptosis was determined by flow cytometric analysis of annexin-V binding,and by terminal transferase-mediated dUTP-fluorescensin nick end-labeling(TUNEL) technique in the presence or absence of synovial fluids from 19 RA patients and 11 OA patients.Results In the presence of RA SF,the rate of neutrophil apoptosis was reduced from 43.6% to 18.3%(P0.01) as detected by flow cytometric analysis;and from 37.4% to 13.7%(P0.01) as assayed by TUNEL method.Whereas,no significant change of neutrophil apoptosis was observed in the persence of OA SF.Conclusion This study indicates that RA SF is capable of slowing the rate of neutrophil apoptosis,and that flow cytometric analysis of annexin-V binding is more sensitive than TUNEL method in detection of cell apoptosis.