牦牛乳酪蛋白降血压肽对高血压大鼠体内降压效果研究

目的：观察牦牛乳酪蛋白降血压肽对应激性高血压大鼠（stress induced hypertensive rats,SIHR）和正常Wistar大鼠的降压效果,并与降压药物厄贝沙坦（irbesaran）和卡托普利（Captopril）的作用效果进行比较。方法：采用木瓜蛋白酶、中性蛋白酶水解制备牦牛乳酪蛋白降血压肽,分别以20 mg/kg、40 mg/kg和60 mg/kg剂量的牦牛乳酪蛋白降血压肽一次灌胃,每隔2 h测量SIHR收缩压（SBP）,连续测量8 h;长期实验持续6周,每天60 mg/kg一次灌胃,每隔1周测量SBP一次。结果：SIHR给予牦牛乳酪蛋白降血压肽后,血压均显著下降（P〈0.05）,并均在灌胃后3-6 h达最低,血压下降最大幅度为（27±5.13）mmHg,呈现一定的量效关系;而正常大鼠给予牦牛乳酪蛋白降血压肽后血压无显著变化,服用厄贝沙坦和卡托普利后血压则保持显著下降的趋势。长期灌胃牦牛乳酪蛋白降血压肽可使SIHR血压明显下降（P〈0.05）,并且降压效果稳定。结论：牛乳酪蛋白降血压肽对SIHR有明显的体内降压效果,长期服用可稳定血压,对正常大鼠血压无明显影响。

Study on antihypertensive effect of antihypertensive peptide from enzymic hydrolysate of yak milk casein in stress induced hypertensive rats in vivo

Objective：To observe the antihypertensive effect of enzymic hydrolysate from yak milkcasein on stress induced hypertensive rats（SIHR） and normal blood pressure Wistar rats in vivo,and compare with the medicine irbesaran and captopril. Methods：Antihypertensive peptide was prepared fromyak milk casein by composite enzyme（papain and neutral protease）,and a single medication at different doses of antihypertensive peptide（20 mg/kg,40 mg/kg and 60 mg/kg）,irbesaran（16.5 mg/kg） and captopril（2.25 mg/kg） were intragastric administered. After administration,systolic blood pressure（SBP） was measured every 2 h continuously for 8 h. While long-term medication lasted for 6 weeks,offered 60mg/kg daily and the SBP were determined every other week. Results：The results showed that after the administrations of antihypertensive peptide from yak milk casein,irbesaran and captopril,the blood pressure of SIHR all decreased（P〈0.05）with a certain dose-effect relationship,and the lowest value was 27 ±5.13 mmHg 2 to 3 hours after administration.Meanwhile irbesaran and captopril could also reduce the blood pressure of normotensive Wistar rats,but antihypertensive peptide had no effect on them. The high dose of antihypertensive peptide could significantly reduced the blood pressure of SIHR in long-term administration experiment. Conclusion：Anihypertensive peptide from yak milk casein has significant antihypertensive effects on SIHR,and could stabilize blood pressure by long-term intake. The antihypertensive effect of irbesaran and captopril on SIHR was higher than antihypertensive peptide from yak milk casein. However,the latter has no influence on blood pressure of normotensive rats.