Total flavonoids of Bidens bipinnata L. ameliorate experimental adjuvant-induced arthritis through induction of synovial apoptosis

BACKGROUND Bidens bipinnata are widely distributed in China, which have been widely used as a traditional Chinese medicine. The aim of this study was to examine the effect of total flavonoids of Bidens pilosa L. (TFB) on adjuvant arthritis (AA) and its possible mechanisms. METHODS The macroscopic scoring of paw edema, secondary paw swelling, and polyarthritis index were measured. Histological examination of the joints and the serum concentrations of IL-6, IL-1beta, and TNF-alpha were examined. Apoptosis in synovial tissue was detected. The expression of Caspase 3 cleavage, serves as a marker undergoing apoptosis, was confirmed by Western blot. RESULTS TFB attenuated the severity of arthritis on paw edema, hind paw volume, and polyarthritis index of AA rats, improved the histological status in AA rats as well. TFB can inhibit the production of IL-6, IL-1beta, and TNF-alpha from serum. Clear DNA ladder formation was observed in DNA extraction of synovium from TFB treated AA rats. The number of apoptosis was increased with TFB treatment in TUNEL assay. TFB treatment on AA rats significantly increased the expression of Caspase 3 in synovium. CONCLUSIONS Our data suggest that TFB has a significant anti-arthritic effect in AA through the induction of apoptosis in synovial.