上调血红素氧合酶-1对尿酸介导脂肪细胞功能障碍的影响及可能机制

Effects and mechanisms of up-regulation of heme oxygenase-1 on uric acid-induced adipocyte dysfunction

目的探讨上调血红素氧合酶-1（HO-1）对尿酸介导的脂肪细胞功能障碍的影响及可能机制。方法体外培养人类骨髓来源的间充质干细胞（Mscs），选用2～3代的MsCs。在脂肪细胞诱导分化培养基中继续培养，分别加入不同浓度的果糖、尿酸，确定最佳浓度。在此基础上，分别依次加人HO-1诱导物钴原卟啉（CoPP）及H0—1活性抑制剂锡中卟啉（SnMP），每组5个独立样本。采用分光光度计法测量MSCs衍生的脂肪细胞脂肪形成的量、脂滴大小，采用免疫印迹法检测黄嘌呤氧化酶（XO）、还原型辅酶II（NADPH）氧化酶的表达水平，采用发光光谱仪测量超氧化物的水平，采用实时聚合酶链反应（PCR）测量脂肪形成标记物及HO-1的水平。结果与对照组比较，浓度为500μmol／L的果糖、50mg／L的尿酸分别使脂肪形成量增加（均P〈0．05）。使用果糖处理的MSCs衍生的脂肪细胞中XO和尿酸的水平高于对照组（P〈0．05）。同时使用果糖和CoPP处理MSCs可有效地将XO和尿酸降低至对照组水平，加入SnMP后则消除了CoPP的有益效果。与对照组比较，尿酸处理后小脂滴的数目减少（P〈0．05），脂肪形成标记物Mest、FAS、PPART及C／EBPa的水平及NADPH氧化酶、超氧化物的水平升高（均P〈0．05），尿酸与CoPP的同时使用可有效地将上述指标逆转至对照组水平。尿酸降低了wnt10b的表达，但对HO-1表达无影响。同时加入CoPP后，HO-1和Wnt10b表达增加至高于对照组的水平（均P〈0．05）。结论上调HO—1可降低XO、尿酸及MsCs衍生的脂肪细胞脂肪生成的水平，降低脂肪形成标记物及NADPH氧化酶和超氧化物的水平，发挥抗氧化应激的作用。HO—1激动剂未来可能会成为老年肥胖和代谢综合征患者的靶器官损伤及体质指数控制的治疗靶点。

Objective To investigate the effects and mechanisms of up-regulation of heme oxygenase-1（HO-1） on uric acid-induced adipocyte dysfunction. Methods Human bone marrow- derived mesenchymal stem eells（MSCs）were cultured in vitro and second or third generation MSCs were selected and recultured in an adipogenic induction medium, with the addition of various amounts of fructose and uric acid to find the optimal concentrations. Then, the HO-1 inducer cobalt protoporphyrin （CoPP） and the HO-1 inhibitor tin porphyrin （SnMP）were added successively. There were five independent samples in each group. Adipogenesis in MSC-derived adipocytes and droplets were measured by spectrophotometry, expression levels of xanthine oxidase （XO） and NADPH were measured by Western blott, superoxide levels were measured by Luminous spectrometer, and levels of adipogenic markers and HO-1 were measured by reverse transcription-polymerase chain reaction（RT-PCR）. Results Fructose at 500 μmol/L and uric acid at 50 mg/L were the optimal concentrations for stimulating adipogenesis in MSC-derived adipocytes （P〈 0.05 ）. Compared with the controls, fructose significantly increased the levels of XO expression ancl uric acid（P〈 0.05）, and concurrent treatment with fructose and CoPP effectively reversed both XO and uric acid levels to those of the controls（all P〈 0.05）. However, SnMP negated the beneficial effects of CoPP （P〈 0.05 ）. Additionally, uric aciddecreased the number of small droplets and increased expression levels of adipogenic markers and NADPH（all P〈0.05）, but proadipogenie mediator levels were reduced with the addition of CoPP（all P 〈0.05）. Furthermore,uric acid reduced expression levels of Wnt10b, but had no significant effect on HO-1 expression,andthese effects were reversed upon the addition of CoPP（all P〈0.05）. Conclusions Upregulation of HO-1 can reduce the levels of XO and uric acid, adipogenesis in MSC-derived adipoeytes,and also the expression of adipogenic markers and NADPH. Therefore, it plays a role in antioxidant stress. HO-1 agonists may be targets for treating organ damage and controlling weight in elderly obese patients with metabolic syndrome.