Ma Rui-xia, Xu Yan, Zhang Juan, Li Yu-shan, Liu Li-qiu
Department of Nephrology, Qingdao University, Qingdao, China.
Zhonghua Nei Ke Za Zhi. 2012 Feb;51(2):117-22.
To investigate the protective effect of combination of triptolide and irbesartan on the podocytes in a type 2 diabetic(T2DM) rat model, and evaluate its mechanism.
T2DM rats were induced by fed with high-sucrose-high-fat diet combined with a low dose of streptozocin. The rats were randomly divided into 5 groups: normal control group (NC, n = 10), diabetes group (DM, n = 11), triptolide treatment group (DT, n = 12), irbesartan treatment group (DI, n = 12) and triptolide combined with irbesartan treatment group (DTI, n = 13). Ultrastructure of podocytes was observed by electronic microscopy and urinary albumin (UAL) excretion by ELISA was determined after 8 weeks. The expression of nephrin and bone morphogenetic protein-7 (BMP-7), connective tissue growth factor (CTGF), transforming growth factor (TGF)β(1) mRNA and proteins were detected by immunohistochemistry, real-time PCR and Western blot.
Increased UAL was significantly attenuated in all treatment groups. Compared to NC group, UAL in DM group was increased significantly (0.45 ± 0.09 vs 6.36 ± 0.87, P < 0.01), while decreased in triptolide or irbesartan alone treatment group (2.48 ± 0.37 and 2.68 ± 0.42, both P < 0.01). Compared with those in control groups, kidney expression of nephrin, BMP-7 mRNA and proteins were downregulated while CTGF, TGFβ(1) mRNA and proteins were significantly upregulated in T2DM rats. Triptolide or irbesartan each alone moderately ameliorated albuminuria and podocyte damage. However, their combined usage showed a dramatic therapeutic synergism, manifested by prevention of progressive albuminuria, restoration of the glomerular filtration barrier, reversal of the decline in slit diaphragm proteins, reduction expression of CTGF, TGFβ(1), and upregulation of BMP-7.
Our findings show that triptolide can increase the efficacy of irbesartan, leading to a more effective prevention of kidney disease in T2DM rat model, which may through upregulation of BMP-7 and inhibition the over-expression of CTGF and TGFβ(1).
研究雷公藤甲素与厄贝沙坦联合应用对2型糖尿病（T2DM）大鼠模型足细胞的保护作用，并探讨其作用机制。
采用高糖高脂饮食联合小剂量链脲佐菌素诱导建立T2DM大鼠模型。将大鼠随机分为5组：正常对照组（NC，n = 10）、糖尿病组（DM，n = 11）、雷公藤甲素治疗组（DT，n = 12）、厄贝沙坦治疗组（DI，n = 12）和雷公藤甲素与厄贝沙坦联合治疗组（DTI，n = 13）。8周后，通过电子显微镜观察足细胞超微结构，采用酶联免疫吸附测定法（ELISA）检测尿白蛋白（UAL）排泄量。通过免疫组织化学、实时荧光定量聚合酶链反应（real-time PCR）和蛋白质免疫印迹法（Western blot）检测nephrin、骨形态发生蛋白-7（BMP-7）、结缔组织生长因子（CTGF）、转化生长因子（TGF）β(1)的mRNA和蛋白表达。
所有治疗组的UAL增加均显著减轻。与NC组相比，DM组的UAL显著增加（0.45±0.09 vs 6.36±0.87，P < 0.01），而雷公藤甲素或厄贝沙坦单独治疗组的UAL降低（2.48±0.37和2.68±0.42，均P < 0.01）。与对照组相比，T2DM大鼠肾脏中nephrin、BMP-7的mRNA和蛋白表达下调，而CTGF、TGFβ(1)的mRNA和蛋白表达显著上调。雷公藤甲素或厄贝沙坦单独使用均可适度改善蛋白尿和足细胞损伤。然而，二者联合使用显示出显著的治疗协同作用，表现为预防进行性蛋白尿、恢复肾小球滤过屏障、逆转裂孔隔膜蛋白的下降、降低CTGF、TGFβ(1)的表达以及上调BMP-7。
我们的研究结果表明，雷公藤甲素可增强厄贝沙坦的疗效，从而更有效地预防T2DM大鼠模型中的肾脏疾病，这可能是通过上调BMP-7以及抑制CTGF和TGFβ(1)的过度表达实现的。
