Effects of amygdalin on type II collagen-induced arthritis in rats

Amygdalin is the active ingredient of Semen Armeniacae Amarum and has anti-inflammatory effects. However, the role of amygdalin in type II collagen-induced arthritis (CIA) is still unknown. In this study, a rat model of CIA was successfully established in female Wistar rats, as demonstrated by severe joint inflammation. The rats were then intragastrically administrated with Tripterygium Glucosides (TG), high dose amygdalin (120 mg kg(-1) d(-1)), low dose amygdalin (60 mg kg(-1) d(-1)) or sterile phosphate-buffered saline (control) for 28 days. Gross morphology and H&E staining showed that treatment with amygdalin significantly alleviated the joint inflammation, similar to the effect of TG. Furthermore, immunohistochemistry, ELISA and qRT-PCR analysis displayed that amygdalin significantly reduced IL-1 beta and TNF-alpha levels compared with model group in both synovial tissue and serum. These findings indicate that amygdalin has treatment effect for arthritis probably through inhibiting the expression of inflammatory cytokines of IL-1 beta and TNF-alpha.