Elevated Expression Of Urotensin Ⅱ And Its Receptor In Great Artery Of Type 2 Diabetes And Its Significance

ObjectivesThis study was designed to investigate the role and significance of UrotensinⅡand its receptor (GPR14) in the formation and development of the diabetic vascular complications, And to explor a new way to prevent and treat the diabetic vascular complications. MethodsTest subjects were divided into spontaneous diabetic modle GK rats and normal Wistar rats group. Each rat weighing approximately 300-350g was 3-5 months old. All rats were kept (three per cage) in 20×40×60-cm cages and fed with standard rat diet and water ad libitum throughout the experiment. One week later, blood glucose levels were measured randomly. The glucose of GK rat that didn't reach 11. lmmol/L and the Wistar rat that exceeded 11. lmmol/L was abandoned. The suitable rats were killed and from its ascending aorta till thoracic aorta were cut immediately in the bacteria- free environment. After cut the aorta from rat we select several piece organizations randomly to do some frozen sections and then HE and oil red 0 stain. Then remaining aorta was divided into two. One portion was soaked in 4% paraformaldehyde. The other portion was frozen in-80℃. The piece that was soaked would be embedded in paraffin for immunohistochemistry. The portion frozen in -80℃is for RT-PCR. Through the HE staining and oil red 0 staining selected the requirement of experiment aorta. By immunohistochemistry to understand urotensin II and its receptor expression location and the level of its expression compared with the control group. By RT-PCR detection of urotensinⅡand its receptor we see the amount of mRNA expression compared with the control group and its significance.Results1. By random blood glucose test, the glucose of GK rat that didn t reach 11. lmmol/L and the Wistar rat that exceeded 11.lmmol/L was abandoned.2. Through the HE stain and the oil red 0 we get the aortic meet the following criteria:①there is a clear delineation of the endomembrane, the tunica media and the adventitia.②The luminal surface is covered by the single endothelial cell layer.③The endothelial cell is integrity and successive.④Smooth muscle cells and elastic fiber has clear border arranged in regular.⑤The is no Fatty streak, no Fibrous plaque, and no Atheromatous plaque. At last we get 16 GK rats and 19 Wistar rats respectively.3.From the Immunohistochemistry we can see that the UⅡand UT were highly up-regulated in the aorta wall of GK rat compared with the wistar rat. Especially the U-Ⅱ, it was significantly enhanced both in the endothelia cell and in the adventitia of GK rat. But the UT was only highly expressed in the endothelia cell compared with the healthy rat. In the adventitia there is no difference between the GK rat and the Wistar rat. From the immunohistochemistry we also can see the stain of adventitia is wide and diffuse.4. The results of RT-PCR is mainly the same as the immunohistochemistry results. After we calculate the ratio between the relative amounts of U-ⅡmRNA and his internal referenceβ-actin, UT mRNA and his internal reference GAPDH, we analyze the date by spss 16.0. We find the mRNA of UⅡand UT were highly up-regulated in the endangium of artery(P<0.01). In the adventitial UT mRNA is no difference between the GK rat and the Wistar rat (P>0.05) while U-ⅡmRNA is highly enhanced in GK rat(P<0.01).ConclusionsThrough the test analysis we found that urotensinⅡand its receptor has high expression in the artery before the occurrence of vascular complications of diabetes. Combined with the analysis of the urotensinⅡand its receptor's Genetic characteristics, expression site, signal transduction. We speculate that urotensinⅡand its receptor is in the initial role in the diabetic vascular complications, will play an active role in prevention and treatment.