人组织型激肽释放酶基因降低果糖诱导高血压大鼠的血压并改善高胰岛素血症

Delivery of Human Tissue Kallikrein Gene Mediates Reductions in Blood Pressure and the Levels of Plasma Insulin and Blood Glucose in Fructose-Induced Hypertensive Rats with Diabetes

目的:研究人组织型激肽释放酶(HK)基因导入对果糖诱导高血压和胰岛素对抗的作用。方法:雄性Sprague-Dawley(SD)大鼠饮用10％的果糖水诱导制成高血压动物模型,2周后静脉注入含人组织型激肽释放酶cDNA的重组质粒。然后监测血压,并取血,测定血糖、血胆固醇、血甘油三脂及血胰岛素水平。结果:一次静脉注射含人组织型激肽释放酶基因的重组质粒第3天即可明显降低果糖诱导高血压大鼠的血压,最大降压效应在导入基因后第14天,其降压效应持续3周以上。实验组动物在血压下降的同时,血糖、血胰岛素浓度亦明显降低,并在动物主要脏器中检测到HK蛋白质的表达显著增加。结论:人组织型激肽释放酶基因的导入可能有助于降低血压,并纠正了高血压伴随的高胰岛素血症,结果提示人组织型激肽释放酶基因治疗高血压病尤其是合并糖尿病或胰岛素对抗者的可行性。

Objective Tissue kallikrein cleaves kininogen substrate to produce the potent vasodilating peptide kinin, which plays important roles in cardiovascular diseases. Hypertension is a muhigene disease and is usually companied with diabetes or hyperinsulinemia. In this study, we investigated therapeutic effects of kallikrein gene delivery on the hypertension as well as diabetes in fructose-induced hypertensive rats with hyperinsulinemia. Methods Male Sprague-Dawley rats were fed with high-fructose （10%）water to develop mild hypertensive models. Plasmid pcDNA3.1 carrying human tissue kallikrein cDNA（HK） （2.5 microgram/kg body weight for each rat）was delivered into high fructose-induced hypertensive rats （n = 6）after 2 weeks through the sublingual vein and empty plasmid was injected as control group （n = 6）. The caudal arterial pressure was measured twice a week for 5 weeks until the animals were sacrificed. The blood was collected for determination of the levels of blood glucose and insulin before plasmid injection and sacrificed, respectively. Results A single intravenous injection of pcDNA-HK resulted in a signifi- cant reduction in blood pressure beginning 3 days after injection and the effect lasted for 3 weeks. And it is very surprised that the levels of plasma insulin and blood glucose were reduced to normal levels in HK-treated rats, although all animals were kept in feeding with 10% fructose water. But the rats in control had nothings changed compared with those before plasmid injection. The expression of human kallikrein was detected in rat main organs by Western Blot and in blood and urine by ELISA in pcDNA-HK treated rats. Conclusion These results indicate that human kallikrein gene transfer induces a dominantly reduction in high blood pressure as well as the high levels of plasma insulin and glucose in fructose-induced hypertensive rats with hypcrinsulinemia and hyperglycemia, which raises the feasibility of applying HK gene to treat human diabetes and hypertension.