黄腐酚对高尿酸血症大鼠血尿酸水平及骨代谢的调控作用

Regulation of xanthohumol on serum uric acid level and bone metabolism in hyperuricemia rats

目的考察黄腐酚(XAN)对高尿酸血症(HUA)大鼠的降血尿酸(UA)及调控骨代谢活性作用。方法将48只雄性Wistar大鼠随机分为6组(n=8):空白组,模型组,别嘌醇(ALLO)组,黄腐酚低剂量(XAN-L)组、中剂量(XAN-M)组、高剂量(XAN-H)组。采用氧嗪酸钾(200 mg·kg^(-1)·d^(-1))与次黄嘌呤(250 mg·kg^(-1)·d^(-1))联用法建立HUA模型。造模2 h后,各药物组分别给予相应药物混悬液(ALLO 20 mg·kg^(-1)·d^(-1),XAN5 mg·kg^(-1)·d^(-1),XAN 15 mg·kg^(-1)·d^(-1),XAN 45 mg·kg^(-1)·d^(-1)),灌胃干预14 d。分别于第3、7、10、14天进行眼眶取血,检测血清中UA、肌酐(CRE)、尿素氮(BUN)水平及黄嘌呤氧化酶(XOD)活性。实验结束测定碱性磷酸酶(ALP)活性,以及骨代谢相关蛋白Runt相关转录因子2(Runx2)、组织蛋白酶K(CTSK)、核因子κB受体活化因子配体(RANKL)和护骨因子(OPG)水平,并对RANKL/OPG比值进行分析。结果与空白组相比,第3、7、10、14天模型组大鼠血清UA水平升高(均P<0.01),表明大鼠HUA模型成功构建。与模型组相比,XAN-M、XAN-H可有效降低急、慢性HUA大鼠血清UA水平(均P<0.01)、抑制XOD活性(均P<0.01)、改善肾功能指标CRE(均P<0.01)和BUN(均P<0.05)。XAN-L虽未明显降低急性HUA大鼠的血清UA水平,但可有效降低XOD活性(P<0.01),并改善其肾功能指标CRE(P<0.01)和BUN(P<0.05);而对于慢性HUA大鼠,其能够有效降低血清UA水平(均P<0.01),却无明显肾保护作用。各剂量组XAN还可不同程度增强HUA大鼠的ALP活性(均P<0.01)、上调Runx2表达(XAN-L组除外,均P<0.01)、下调CTSK的表达(均P<0.01)、抑制RANKL分泌(均P<0.01)、促进OPG的表达(仅XAN-H组,P<0.01)、纠正RANKL/OPG的比值(均P<0.05)。结论XAN具有降低HUA大鼠血UA水平的作用,这可能与其抑制XOD活性以减少UA生成及保护肾功能以加强UA排泄有关;XAN还具有促进骨形成、抑制骨破坏,有效调控骨代谢的作用,这可能与其通过RANKL/OPG信号通路抑制破骨细胞分化有关。

Objective To investigate the effects of xanthohumol(XAN)on reducing serum uric acid(UA)and regulating bone metabolism in hyperuricemia(HUA)rats.Methods Totally 48 male Wistar rats were randomly divided into 6 groups(n=8):blank group,model group,allopurinol(ALLO)group,XAN low-dose(XAN-L)group,XAN medium-dose(XAN-M)group,and XAN high-dose(XAN-H)group.The HUA model was developed by the combined use of potassium oxonate(200 mg·kg^(-1)·d^(-1))and hypoxanthine(250 mg·kg^(-1)·d^(-1)).After HUA model was established for 2 h,corresponding concentrations of drug suspension(20 mg·kg^(-1)·d^(-1) in ALLO group,5 mg·kg^(-1)·d^(-1) in XAN-L group,15 mg·kg^(-1)·d^(-1) in XAN-M group,and 45 mg·kg^(-1)·d^(-1) in XAN-H group)was administered to gavage for 14 d.Orbital blood was collected on the 3rd,7th,10th and 14th d to detect the levels of serum UA,creatinine(CRE),blood urea nitrogen(BUN),and activity of xanthinoxidase(XOD)in each group.At the end of the experiment,the activity of alkaline phosphatase(ALP),the levels of bone metabolism-related proteins such as Runt-related transcription factor 2(Runx 2),cathepsin K(CTSK),receptor activator of nuclear factor kappa B ligand(RANKL)and osteoprotegerin(OPG)were measured,and then the ratio of RANKL/OPG was analyzed.Results Compared with the blank group,the serum levels of UA in rats of model group were significantly increased on the 3rd,7th,10th and 14th d(all P<0.01),indicating that the HUA model was successfully constructed.Compared with the model group,both XAN-M and XAN-H effectively reduced the levels of serum UA in acute and chronic HUA rats(all P<0.01),inhibited the XOD activity(all P<0.01),and improved the renal function indexes CRE(all P<0.01)and BUN(all P<0.05).Although XAN-L did not significantly reduce the serum UA level in acute HUA rats,it effectively decreased the XOD activity(P<0.01)and improved its renal function indexes CRE(P<0.01)and BUN(P<0.05);while for chronic HUA rats,it had descending effects on the serum UA level(all P<0.01),but had no obvious renal protective effect.In addition,XAN also significantly enhanced ALP activity(all P<0.01),up-regulated the expression of Runx2(all P<0.01,except for XAN-L group),down-regulated the expression of CTSK(all P<0.01),inhibited the secretion of RANKL(all P<0.01),promoted the expression of OPG(P<0.01,only for XAN-H group),and corrected the ratio of RANKL/OPG(all P<0.05).Conclusion XAN has active descending effects on serum levels of UA in HUA rats,which may be related to inhibiting XOD activity to reduce UA production and protecting renal function to enhance UA excretion.Meanwhile,XAN can also promote bone formation,inhibit bone destruction,and effectively regulate bone metabolism,which may be related to the inhibition of osteoclast differentiation through RANKL/OPG signaling pathway.