Zhang Z, Li L, Li Z K, Wu F, Hang B Y, Cai B Y, Weng Z F, Zhao L, Ding C F, Du Y G
the 2nd Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou 310053, China.
Zhonghua Yi Xue Za Zhi. 2018 Jun 12;98(22):1792-1796. doi: 10.3760/cma.j.issn.0376-2491.2018.22.013.
To observe the effects of mulberry leaf polysaccharide (MLP) on insulin-like growth factor 1 (IGF-1) and insulin-like growth factor blinding protein 3 (IGFBP-3) as well as the expression of IGF-1 and IGFBP-3 mRNA in the kidney of type 1 Diabetic Nephropathy (DN) rats, and to investigate its therapeutic effects and underlying mechanisms. Type 1 DN rat model was established by intraperitoneally injecting streptozocin (STZ). SD rats were randomly divided into the control, model, insulin and MLP groups, with eight rats in each group. Rats in MLP group were given orally with MLP 200 mg/kg daily for 8 weeks and insulin group rats were given subcutaneously injection of short acting insulin 1 U daily for 8 weeks. The changes in body weight, blood and urine parameters were recorded. Extracellular matrix (ECM) was calculated. The contents of IGF-1 and IGFBP-3 in blood serum were evaluated by enzyme-linked immunosorbent assay (ELISA). The mRNA expressions of IGF-1 and IGFBP-3 in the kidney were evaluated by fluorescence quantitative PCR. Compared with rats in control group, blood glucose, triglyceride, total cholesterol, low density lipoprotein, very low density lipoprotein, 24 h urine protein, serum creatinine and urea nitrogen in the model group rats were significantly increased (all <0.01), and these parameters of MLP group were significantly lower than the model group (all <0.01). The contents of IGF-1 and IGFBP-3 in the blood serum of the model group were significantly higher than those in the control group (both <0.001), while in the MLP group they were lower than the model group[IGF-1: (0.777±0.018) ng/ml vs (0.864±0.022) ng/ml, <0.001; IGFBP-3: (0.759±0.016) ng/ml vs (0.846±0.021) ng/ml, <0.001]. The mRNA expressions of IGF-1 and IGFBP-3 in the kidney of the model group were significantly higher than those in the control group (both <0.001), while in the MLP group they were lower than in the model group (IGF-1: 1.450±0.032 vs 1.810±0.090, <0.001; IGFBP-3: 1.684±0.018 vs 1.968±0.044, <0.001). Compared with the model group rats, there were fewer pathological changes of kidney in MLP group rats. MLP has a certain therapeutic effect on DN, which may be achieved by decreasing the contents of IGF-1 and IGFBP-3 in the blood serum and down-regulating the over-expression of IGF-1 and IGFBP-3 mRNA in the kidney.
观察桑叶多糖（MLP）对1型糖尿病肾病（DN）大鼠肾脏中胰岛素样生长因子1（IGF-1）、胰岛素样生长因子结合蛋白3（IGFBP-3）及IGF-1和IGFBP-3 mRNA表达的影响，探讨其治疗作用及潜在机制。采用腹腔注射链脲佐菌素（STZ）建立1型DN大鼠模型。将SD大鼠随机分为对照组、模型组、胰岛素组和MLP组，每组8只。MLP组大鼠每日灌胃给予MLP 200 mg/kg，连续8周；胰岛素组大鼠每日皮下注射短效胰岛素1 U，连续8周。记录体重、血液和尿液参数变化。计算细胞外基质（ECM）。采用酶联免疫吸附测定（ELISA）法检测血清中IGF-1和IGFBP-3含量。采用荧光定量PCR法检测肾脏中IGF-1和IGFBP-3 mRNA表达。与对照组大鼠相比，模型组大鼠血糖、甘油三酯、总胆固醇、低密度脂蛋白、极低密度脂蛋白、24 h尿蛋白、血清肌酐和尿素氮均显著升高（均P<0.01），MLP组上述指标均显著低于模型组（均P<0.01）。模型组血清中IGF-1和IGFBP-3含量显著高于对照组（均P<0.001），而MLP组低于模型组[IGF-1：（0.777±0.018）ng/ml对（0.864±0.022）ng/ml，P<0.001；IGFBP-3：（0.759±0.016）ng/ml对（图0.846±0.021）ng/ml，P<0.001]。模型组肾脏中IGF-1和IGFBP-3 mRNA表达显著高于对照组（均P<0.001），而MLP组低于模型组（IGF-1：1.450±0.032对1.:810±0.090，P<0.001；IGFBP-3：1.684±0.018对1.968±0.044，P<0.001）。与模型组大鼠相比，MLP组大鼠肾脏病理改变较少。MLP对DN有一定治疗作用，其机制可能是通过降低血清中IGF-1和IGFBP-3含量及下调肾脏中IGF-1和IGFBP-3 mRNA的过表达来实现。
