C型利钠肽在糖尿病下肢动脉硬化发生中的作用

Diabetic atherosclerosis(ASO) on lower extremity is one of the most severe complications of Diabetes mellitus.However,its mechanism has not been clarified thoroughly.Vascular endothelial disfunction is the key pathogenesis of Diabetic ASO on lower extremity .C-type natriuretic peptide (CNP) has been found to preserve and restore normal function vascular endothelium in present studies..In our preliminary test, CNP level dicreased markedly in patients of Diabetic ASO on lower extremity and CNP expression reduced significantly in animal model of Diabetic ASO on transcriptional and translational aspects. Therefore, is there any distinction on mechanism of Diabetic ASO between these two categories? Does CNP has optimistic role on prevention of Diabetic ASO?.In this study, we plan to identify the effect of CNP on occurrence of Diabetic ASO.Firsty,we prepare to confirm the expression variation of plasm CNP in patients of Diabetic ASO .Subsequently, the relativity between CNP expression and Diabetic ASO degree will be discussed. Then, CNP transgenic mice of 2 type diabetes millus animal model,KK-Ay mice, will be designed to testify whether CNP augmentation has negative contribution on Diabetic ASO progress. Meanwhile, CNP gene knock-out KK-Ay mice (CNP-/-) will be reconstructed to probe whether CNP inhibition has positive role on Diabetic ASO development. Then,the effect of CNP on Diabetic ASO of lower extremity will be clarified.Endly, the protein of CNP will be applied systematiclly in diabetes animal model of KK-Ay mice to testify its contribution on Diabetic ASO of lower extremity. The results of the present study is expected to provide theoretical and experimental foundation to apply CNP on Diabetic ASO prevention in next clinical trial.

糖尿病下肢动脉硬化是糖尿病严重并发症之一，其发病机制中血管内皮功能紊乱是根本原因。C型利钠肽（CNP）在维持血管内皮功能、促进血管内皮修复方面具有重要作用。我们前期研究和预实验发现：糖尿病下肢动脉硬化患者血浆CNP水平较无下肢动脉硬化糖尿病患者明显降低，动物模型显示股动脉CNP表达在转录和翻译水平均显著降低。因此，CNP在糖尿病下肢动脉硬化发生中是否具有作用？我们拟探讨CNP与糖尿病下肢动脉硬化的相关性，然后利用自发性2型糖尿病KK-Ay小鼠，构建CNP转基因糖尿病KK-Ay小鼠、CNP基因敲除糖尿病KK-Ay小鼠（CNP-/-），探讨CNP基因过表达和基因敲除后对糖尿病下肢动脉硬化的影响，从正反两方面阐明CNP在糖尿病下肢动脉硬化发生中的作用。最后，我们将CNP蛋白全身应用于糖尿病KK-Ay小鼠模型观察对糖尿病下肢动脉硬化的影响，为将来开展CNP干预糖尿病下肢动脉硬化的临床研究做准备。

C型利钠肽（C-type natriuretic peptide, CNP）在维持血管内皮功能、促进血管内皮修复方面具有重要作用。我们前期研究发现：糖尿病下肢动脉硬化（diabetic atherosclerosis obliterans, DASO）患者血浆CNP水平降低。CNP在DASO发生中是否具有作用？我们拟明确CNP与DASO的相关性，然后构建CNP基因敲除糖尿病小鼠（CNP-/-）和CNP转基因糖尿病小鼠（CNP+/-）；再将CNP蛋白应用于糖尿病小鼠。探讨CNP基因敲除和增加CNP后对DASO的影响，为将来开展CNP干预糖尿病下肢动脉硬化的临床研究做准备。.本研究证明了CNP与糖尿病下肢动脉硬化之间有明显相关性：糖尿病下肢动脉硬化患者血浆CNP含量明显低于糖尿病未发生下肢动脉硬化患者。糖尿病下肢动脉硬化患者血浆CNP水平与下肢缺血评分呈负相关（r=-0.734，p0.000）、股动脉内中膜厚度呈负相关（r=-0.611，p=0.000）；与下肢动脉峰值血流比值呈负性相关（r=-0.843，p=0.000）。糖尿病病程呈负相关（r=-0.258，p=0.07），与空腹血糖含量呈负相关（r=-0.02，p=0.889），与糖化血红蛋白呈负相关（r=-0.153，p=0.288），与低密度脂蛋白胆固醇含量呈负性相关（r=-0.540，p0.000）；与血肌酐含量呈负性相关（r=-0.157，p=0.277），与血管内皮功能呈正相关性（r=0.313，p=0.027）。糖尿病下肢动脉硬化患者缺血代偿期及失代偿期血浆CNP值比较，糖尿病下肢动脉硬化缺血代偿期患者血浆CNP含量均值为6.15±1.64pg/ml (n=32), 而缺血失代偿期患者血浆CNP含量均值为1.52±1.24 (n=68), 差异有统计学意义(t=-8.29 , p=0.00)。.成功构建CNP基因敲除糖尿病小鼠（CNP-/-）和CNP转基因糖尿病小鼠（CNP+/-），发现CNP基因敲除可以增加糖尿病下肢动脉硬化的程度，而CNP基因过表达可以抑制糖尿病下肢动脉硬化的程度。全身应用CNP蛋白于糖尿病下肢动脉硬化小鼠模型，发现增加CNP表达后可一定程度抑制糖尿病下肢动脉硬化。为临床上利用CNP干预糖尿病下肢动脉硬化提供了有价值的参考依据。