抹草萃取物改善第二型糖尿病腎病變之體內外研究

糖尿病腎病變(Diabetic Nephropathy, DN)為糖尿病的主要併發症之一。已知抹草萃取物(Desmodium caudatum extract, DCE)有抗發炎及抗氧化的效果，但目前尚未有改善DN和腎臟纖維化的相關研究。本研究透過體內外研究探討DCE是否能改善DN及腎臟纖維化。體內實驗以高脂飲食(High fat diet, HFD)合併鏈脲佐菌素(Streptozotocin, STZ)誘發 C57BL/6 小鼠為DN之實驗動物模式，以每日管餵給予 100 mg/kg 和 200 mg/kg 之 DCE 持續進行治療6 週，並以臨床藥物辛伐他汀(Simvastatin)與二甲雙胍(Metformin)作為實驗對照組；在腎臟組織分析後發現，DCE能減少腎臟脂質及醣類堆積，增加腎臟抗氧化酵素活性並減少纖維化。體外細胞實驗使用DCE及其主要成分異牡荊素(Isovitexin)觀察是否能改善由棕梠酸(Palmitic acid, PA)及高糖(High glucose, HG)誘導大鼠腎小管上皮細胞NRK52E損傷及纖維化，發現DCE能抑制NRK52E細胞脂質及醣化終產物(Advanced glycation end products, AGE)堆積、減少氧化壓力和抑制纖維化蛋白轉化生長因子(Transforming growth factor beta, TGF-β)。上述結果和動物實驗一致。總結，DCE可以透過降低脂質與醣類堆積、減少氧化壓力來改善DN及腎臟纖維化，未來可用於輔助治療DN來延緩其病程進展及改善腎功能。

Diabetic nephropathy (DN) was one of the main complications of diabetes. On the previous studies have found that Desmodium caudatum extracts (DCE) have effects of anti-inflammatory and antioxidants, but there are no report above the improving DN and renal fibrosis yet. In this study we’re use the DCE to improve both DN and renal fibrosis in vitro and in vivo. We used a High-fat diet (HFD) combined with streptozotocin (STZ) to induce DN in C57BL/6 mice, and treated with 100 mg/kg and 200 mg/kg DCE once a day by tube feeding. The treatment was continued for 6 weeks, and the clinical drugs Simvastatin and Metformin were added to the experimental control group. After analyzed kidney tissue, we found that DCE can reduce the accumulation of lipids and carbohydrates in the kidney, increase antioxidants and reduce fibrosis as well. And in cell experiments using DCE and its major component isovitexin to observe whether it can ameliorate the injury induced by palmitic acid (PA) and high glucose (HG) in rat renal tubular epithelial cells NRK52E. After the experiment, we found that the DCE also could inhibit the accumulation of lipid and AGE (advanced glycation end products) in NRK52E cells, reduce oxidative stress and inhibited fibrotic protein transforming growth factor-beta (TGF-β). The results are consistent with animal experiments. In conclusion, DCE can improve DN and renal fibrosis by reducing lipid and carbohydrate accumulation and reducing oxidative stress. In the future, DCE may be used as an adjuvant therapy for DN to improve renal function.