Wu Yonggui, Wang Yan, Qi Xiangming, Zhang Pei, Zhang Chaoqun, Zhang Wei
Department of Nephrology, The First Affiliated Hospital of Anhui Medical University, Hefei, PR China.
Nephron Exp Nephrol. 2014;128(1-2):46-56. doi: 10.1159/000366446. Epub 2014 Nov 5.
BACKGROUND/AIMS: Accumulating evidence suggests that macrophage-induced inflammation may be the mechanism of development and progression of diabetic nephropathy. A previous study by our group has shown that tacrolimus, like cyclosporin A, has a renoprotective effect in diabetic rats. The present study aimed to elucidate the underlying molecular events.
Diabetic rats were induced by using streptozotocin. Diabetic rats were subjected to oral tacrolimus treatment at a dose of 0.5 or 1.0 mg/kg daily for 4 weeks. Body weight, blood glucose, hemoglobin A(1c) (HbA(1c)) and renal pathology were assessed, followed by analyses of renal calcineurin (CaN) expression, changes in renal macrophage infiltration, proliferation and activation, and detection of renal TLR2+ and TLR4+ as well as NF-κB-p-p65+ in macrophages.
Diabetic rats had a reduced body weight and increased blood glucose and HbA(1c) levels, whereas tacrolimus treatment did not affect body weight or blood glucose and HbA(1c). Increased relative kidney weight was only significantly reduced by tacrolimus treatment at a dose of 1.0 mg/kg, while the elevated albumin excretion rate was markedly attenuated after treatment with tacrolimus (0.5 and 1.0 mg/kg) in diabetic rats. Elevated glomerular volume was significantly attenuated by tacrolimus treatment with 0.5 and 1.0 mg/kg, and increased indices for tubulointerstitial injury were only ameliorated by tacrolimus treatment with 1.0 mg/kg. Western blot data showed that expression of CaN protein was induced 2.4-fold in the kidneys of positive control diabetic rats, whereas tacrolimus treatment at 0.5 and 1.0 mg/kg doses reduced the increased expression of CaN protein by 38.0 and 73.2%, respectively. Histologically there was a marked accumulation of ED-1+ cells (macrophages) in diabetic kidneys and tacrolimus treatment failed to inhibit it. In contrast, tacrolimus treatment at 0.5 and 1.0 mg/kg doses significantly inhibited the elevated ED-1+/PCNA+ cells and ED-1+/iNOS+ cells in the kidneys of diabetic rats, while tacrolimus treatment at a dose of 0.5 or 1.0 mg/kg significantly suppressed the increased ED-1+/TLR2+ cells, ED-1+/TLR4+ cells and ED-1+/NF-κB-p-p65+ cells in the kidneys of diabetic rats.
The data from the current study demonstrated that tacrolimus could ameliorate early renal injury through a mechanism to suppress macrophage activation.
背景/目的：越来越多的证据表明，巨噬细胞诱导的炎症可能是糖尿病肾病发生和发展的机制。我们团队之前的一项研究表明，他克莫司与环孢素A一样，对糖尿病大鼠具有肾脏保护作用。本研究旨在阐明其潜在的分子机制。
使用链脲佐菌素诱导糖尿病大鼠。糖尿病大鼠每日口服剂量为0.5或1.0 mg/kg的他克莫司，持续4周。评估体重、血糖、糖化血红蛋白（HbA1c）和肾脏病理学，随后分析肾脏钙调神经磷酸酶（CaN）表达、肾脏巨噬细胞浸润、增殖和活化的变化，以及巨噬细胞中肾脏TLR2+和TLR4+以及NF-κB-p-p65+的检测。
糖尿病大鼠体重减轻，血糖和HbA1c水平升高，而他克莫司治疗不影响体重、血糖和HbA1c。仅1.0 mg/kg剂量的他克莫司治疗可显著降低相对肾脏重量的增加，而糖尿病大鼠用他克莫司（0.5和1.0 mg/kg）治疗后，白蛋白排泄率升高明显减轻。0.5和1.0 mg/kg的他克莫司治疗可显著减轻肾小球体积的增加，仅1.0 mg/kg的他克莫司治疗可改善肾小管间质损伤指数的增加。蛋白质印迹数据显示阳性对照糖尿病大鼠肾脏中CaN蛋白表达增加2.4倍，而0.5和1.0 mg/kg剂量的他克莫司治疗分别使CaN蛋白增加的表达降低38.0%和73.2%。组织学上，糖尿病肾脏中ED-1+细胞（巨噬细胞）明显积聚，他克莫司治疗未能抑制。相反，0.5和1.0 mg/kg剂量的他克莫司治疗可显著抑制糖尿病大鼠肾脏中ED-1+/PCNA+细胞和ED-1+/iNOS+细胞的增加，而0.5或1.0 mg/kg剂量的他克莫司治疗可显著抑制糖尿病大鼠肾脏中ED-1+/TLR2+细胞、ED-1+/TLR4+细胞和ED-1+/NF-κB-p-p65+细胞的增加。
本研究数据表明，他克莫司可通过抑制巨噬细胞活化的机制改善早期肾脏损伤。
