地龙降压蛋白对自发性高血压大鼠血压及血管紧张素Ⅱ含量的影响

目的初步探讨地龙降压蛋白对自发性高血压大鼠（spontaneously hypertension rat,SHR）的降压作用及对血管紧张素Ⅱ（angiotensinⅡ,AngⅡ）含量的影响。方法应用专利技术从中药地龙中提取地龙降压蛋白,并测定其体外ACE抑制活性。单次静脉注射地龙降压蛋白,颈动脉插管法观察SHR血压的动态变化。选择16周龄SHR32只随机分为SHR模型组、地龙降压蛋白低剂量组、地龙降压蛋白高剂量组、卡托普利组,同时以同源性Wistar大鼠8只作为正常对照组,药物干预28d,用无创尾动脉套袖法测量大鼠血压变化;放射免疫分析法测定大鼠血浆及肾脏局部AngⅡ含量。选择昆明种小鼠60只,以不同剂量腹腔注射给药测定地龙降压蛋白的半数致死量。结果①地龙降压蛋白对ACE的比抑制活力为2.54;②单次及多次给药,地龙降压蛋白均可明显降低SHR血压（P〈0.05）;③药物干预后,与SHR模型组比较,地龙降压蛋白组血浆AngⅡ含量显著降低（P〈0.05）,而肾脏局部AngⅡ虽有所下降,但差异无统计学意义（P〉0.05）;④地龙降压蛋白对昆明小鼠的半数致死量〉20g/kg。结论地龙降压蛋白对SHR有降压作用,其降压机制可能与降低血浆及肾脏局部组织中AngⅡ含量有关。

Effects of the antihypertensive protein from earthworm on blood pressure and the level of angiotensin Ⅱin spontaneously hypertension rats

Objective To investigate the effects of the antihypertensive protein from earthworm on blood pressurea and the level angiotensin Ⅱ in spontaneously hypertension rats（SHR）. Methods ① To isolate and purify the antihypertensive protein from earthworm and measure its action of inhibiting angiotensin conver- ting enzyme （ACE） in vitro; ②to investigate the antihypertensive effect of the antihypertensive protein from earthworm in spontaneously hypertension rats by single intravenous injection and repeated intraperitoneal injection; ③to detecte the change in level of angiotensin Ⅱ ;④ to measure the median lethal dose （LD50） of anti-hypertensive protein from earthworm on mice by intravenous injection. Results ①The specific activity to ACE of the anfihypertensive protein from earthworm was 2. 54 ;②the antihypertensive protein from earthworm could reduce the blood pressure in SHR significantly by single intravenous injection or by repeated intraperitoneal in-jection（ P 〈 0. 05 ）;③the antihypertensive protein from earthworm could lower the angiotensin Ⅱ level in plasma, with a significant difference compared with the model group （ P 〈 0. 05 ）, and lower the angiotensin Ⅱ level in tissue of kidney without a significant difference （ P 〉 0. 05 ） ;④the LD50 of the antihypertensive protein from earthwormwas more than 20 g/kg by intraperitoneal injection. Conclusion The antihypertensive protein from earthworm has a significant effect of decreasing blood presure on SHR. The mechanism may be related to its action in reducing angiotensin Ⅱ levels in plasma and in tissue of kidney.