Emodinol ameliorates urate nephropathy by regulating renal organic ion transporters and inhibiting immune inflammatory responses in rats.

Emodinol, 1β, 3β, 23-trihydroxyolean-12-en-28-acid, as the main active ingredient firstly extracted from the rhizomes of Elaeagus pungens by our Research Group, was identified with apparent uricosuric and nephroprotective effects in hyperuricemia mice in our previous study. This study aimed to investigate the renal protective effect of emodinol in urate nephropathy rats. Rats were orally administrated by combined adenine and ethambutol to induce urate nephropathy. Emodinol at various doses were administered intragastrically to urate nephropathy rats daily. Serum uric acid (Sur), serum creatinine (Scr) and blood urea nitrogen (BUN) levels, as well as Interleukin-1beta (IL-1β) and tumor necrosis factor- alpha (TNF-α) concentrations in serum and kidney were determined. Renal protein expressions of organic ion transporters, components of NLR pyrin domain containing 3 (NLRP3) inflammasome, as well as key factors involved in toll-like receptors (TLRs)/myeloid differentiation factor 88 (MyD88)/nuclear factor kappa B (NF-κB) signaling pathway were analyzed by western blot. Emodinol significantly decreased Sur, Scr and BUN levels in adenine and ethambutol - induced urate nephropathy rats. More importantly, emodinol reversed dys-expression of organic ion transporters, inhibited NLRP3 inflammsome activation and suppressed TLRs/MyD88/NF-κB signaling pathway in the kidneys of urate nephropathy rats. Consistently, dilated tubules and tubular UA crystal formation, as well as tubular interstitial inflammatory cells infiltration in kidneys of urate nephropathy rats were obviously attenuated by emodinol, accompanied by restored renal and serum inflammatory cytokines concentrations. Taken together, the date suggested that emodinol ameliorated urate nephropathy by regulating renal organic ion transporters and inhibiting immune inflammatory responses in rats.