Anti-arthritis effect of berberine associated with regulating energy metabolism of macrophage through AMPK/HIF-1α pathway

OBJECTIVE To investigate berberine(BBR) attenuates arthritis in adjuvant-induced arthritic(AA) rats associated with regulating the energy metabolism and correcting the polarization of macrophages through activation of AMP-activated protein kinase(AMPK) and inhibition of hypoxia inducible factor 1α(HIF-1α). METHODS AA rats were treated with BBR(40, 80, or 160 mg·kg~(-1)) from days 15 to 29 after immunization. The histopathology of ankle joint was examined through hematoxylin-eosin(HE) staining. The concentrations of tumour necrosis factor-α(TNF-α), interleukin-6(IL-6), IL~(-1)β, IL-2, IL~(-1)7 A, interferon-gamma(IFN-γ), monocyte chemotactic protein 1(MCP-1), IL-4, IL~(-1)0, transforming growth factor-β1(TGF-β1), ATP, and lactic acid were measured by using ELISA kits. The percentage of M1 and M2 macrophage cells in joint tissues were evaluated by immune-fluorescence. The expressions of p-AMPK and HIF-1α in joint of AA rats were determined according to immunohistochemistry analysis. The migration of macrophage was detected by Transwell assays. The expression of inducible nitric oxide synthase(iN OS), Arginase-1(Arg1), p-AMPK, AMPK and HIF-1αwere examined by Western blotting. The labeled macrophages were observed with laser confocal microscopy.RESULTS BBR relieved signs and symptoms of AA rats and reversed pathological changes. BBR treatment group exhibited decreases in pro-inflammatory cytokines(TNF-α, IL~(-1)β, IL-6, IL-2, IL~(-1)7 A, IFN-γ, and MCP-1) coupled with increases anti-inflammatory cytokines(IL-4, IL~(-1)0, TGF-β1) in the serum. The number of M1 macrophage was reduced,while the number of M2 macrophage was increased in BBR group joint tissues. Moreover, BBR showed marked up-regulation the expression of p-AMPK and down-regulation the expression of HIF-1α in joint of AA rats. Next in vitro study, we found BBR up-regulated the expression of p-AMPK, Arg1(M2 marker) and down-regulated the expression of HIF-1α,i NOS(M1 marker) induced by LPS in peritoneal macrophages from normal SD rat. Furthermore, BBR treatment inhibited the migration of macrophages stimulated by LPS. The level of ATP was elevated and lactic acid was reduced in LPSinduced macrophages after treated by BBR. However, Compound C significantly attenuated the effects of BBR on activated macrophages. CONCLUSION BBR alleviates inflammation by regulating energy metabolism and correcting the polarization of macrophage through AMPK-HIF-1α pathway. BBR might have great therapeutic value for RA.