Anti-inflammatory effect of total saponin fraction from Dioscorea nipponica Makino on gouty arthritis and its influence on NALP3 inflammasome.

OBJECTIVE: To investigate the mechanism of Chinese herbal medicine Dioscorea nipponica for the treatment of monosodium urate crystals-induced gouty arthritis (GA) in rats.

METHODS: Sixty male Wistar rats were divided into 6 groups: normal, model, indomethacin and three total saponin (900, 300 and 100 mg/kg) groups. The liver, kidney and serum levels of lysosomal enzymes, antioxidant capacities, and inflammatory factors were measured. In addition, the mRNA and protein levels of the NALP3 inflammasome components in the mononuclear cells of rats' peripheral blood were analyzed using real-time polymerase chain reaction and Western blotting methods, respectively.

RESULTS: Total saponins groups could reduce the activities of β-galactosidase, β-N acetyl glucosamine enzyme, β-glucuronidase, acid phosphatase, and malonaldehyde as well as the contents of TNF-α, IL-1β and IL-8 (all P<0.05). They could also increase the activities of glutathione peroxidase and total superoxide dismutase (both P<0.05). Further studies showed that total saponins groups of high, middle and low doses could all increase the mRNA and protein levels of caspase-1, adapter apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and NALP3 in the mononuclear cells of peripheral blood (all P<0.05).

CONCLUSION: Dioscorea nipponica may treat GA by regulating lysosomal enzymes, antioxidant capacities and the NALP3 inflammasome.