Ghrelin受体拮抗剂对糖尿病大鼠肝功能的调节及血管功能的保护作用

Effects of Ghrelin Receptor Antagonist on Regulation of Liver Function and Protection of Vascular Function in Diabetic Rats

关键词:  Ghrelin受体激动剂  糖尿病大鼠  肝功能  血管功能  保护

Key words:  Ghrelin receptor antagonist  diabetic rats  liver function  vascular function  protection

摘要:

目的 探究Ghrelin受体拮抗剂对糖尿病大鼠肝功能的调节和血管功能的保护作用及其机制。方法 使用高脂饮食联合链脲佐菌素（streptozocin，STZ）构建糖尿病SD大鼠模型。注射STZ后每周测量体质量和空腹血糖（fasting blood glucose，FBG），持续3周；HE染色评估肝脏损伤程度；ELISA试剂盒分析血清中肝功能相关指标的水平；HE染色测量颈内动脉的新内膜和介质的面积，并计算内膜面积与介质面积的比率（I/M）；免疫组织化学染色评估细胞因子的数量和位置；Western blotting分析大鼠肝组织和颈内动脉内NF-κB，IKKa和p-IKKa蛋白的表达，RT-PCR分析NF-κB，IKKa和p-IKKa mRNA的比率。结果 与对照组相比，模型组大鼠血糖浓度和体质量明显升高，其肝细胞明显受损且肝功能指标明显升高，颈动脉内膜明显增厚以及其内炎性因子细胞间黏附分子-1（intercellular cell adhesion molecule-1，ICAM1）和骨桥蛋白（osteopontin，OPN）表达明显增加，而内皮型一氧化氮合酶（endothelial nitric oxide synthase，eNOS）的表达降低，其肝组织和颈内动脉内IKKa磷酸化明显加强；而经Ghrelin受体拮抗剂治疗明显降低了糖尿病大鼠的血糖浓度和体质量，减弱了其肝脏的损伤，降低了其颈内动脉的内膜厚度以及炎性因子ICAM1和OPN的表达，回升了eNOS的表达，减弱了其肝组织和颈内动脉内NF-κB活化。结论 Ghrelin受体拮抗剂通过促进NF-κB的激活发挥对糖尿病大鼠肝功能的调节和血管功能的保护作用。

Abstract:

OBJECTIVE To investigate the effects of Ghrelin receptor antagonist on regulation of liver function and protection of vascular function in diabetic rats and its mechanism.METHODS Using a high-fat diet combined with streptozotocin(STZ) in SD rats to construct a rat model of diabetes.Body weight and fasting blood glucose(FBG) were measured weekly after injection of STZ for 3 weeks.The degree of liver injury in each group was evaluated by HE staining.The levels of liver function related indexes in the serum of each group were analyzed by ELISA.HE staining was used to measure the area of neointimal and media of the internal carotid artery, and the ratio of intimal area to medium area(I/M) was calculated.Immunohistochemistry (IHC) staining were performed to evaluate the number and location of various cytokines.The expressions of IKKa and p-IKKa protein in liver tissue and internal carotid artery of each group were analyzed by Western blotting.The ratio of NF-κB, IKKa and p-IKKa mRNA was analyzed by RT-PCR.RESULTS Compared with the control group, the blood glucose concentration and body weight of rats in model group were significantly increased, the liver cells were significantly damaged, and the liver function indexes were significantly increased, and the carotid intima was thickened and the expression of inflammatory factors intercellular cell adhesion molecule-1(ICAM1) and osteopontin(OPN) was significantly increased, while the expression of endothelial nitric oxide synthase(eNOS) was decreased, and the phosphorylation of IKKa in liver tissue and internal carotid artery was significantly enhanced.However, Ghrelin receptor antagonist treatment significantly reduced the blood glucose concentration and body weight of diabetic rats, weakened the liver damage, reduced the intimal thickness of the internal carotid artery and the expression of inflammatory factors ICAM1 and OPN, increased the expression of eNOS, and decreased the activation of NF-κB in liver and internal carotid artery.CONCLUSION Ghrelin receptor antagonist plays a role in the regulation of liver function and vascular function in diabetic rats by promoting the activation of NF-κB.