低分子质量κ-卡拉胶钾的酶法制备及其对原发性高血压大鼠降血压作用的研究

Preparation of low-molecular-weight potassium κ-carrageenan by enzymatic hydrolysis and its antihypertensive effect on SHR

为了探究低分子质量κ-卡拉胶钾对原发性高血压大鼠(spontaneously hypertensive rat,SHR)血压的影响,以κ-卡拉胶粉为原料,酶解法和醇沉法相结合制备分子质量为3.5 kDa的低分子质量κ-卡拉胶寡糖(low-molecular-weightκ-carrageenan,LC)。将LC与KCl溶液混合,经醇沉操作除去游离的钾离子,以此获得高结合率的低分子质量κ-卡拉胶钾(low-molecular-weight potassiumκ-carrageenan,LCP),使得LC中结合型钾元素的含量由原先的6.5%上升至8.7%。各组灌胃剂量:实验组600 mg/kg LCP,空白组灌胃蒸馏水,阳性对照组10 mg/kg卡托普利。结果显示,LCP对SHR有稳定且持续的降压作用,与空白组相比,显著降压18 mmHg。LCP显著降低了RAS系统中肾素(P<0.05)和血管紧张素Ⅱ(AngⅡ)(P<0.01)的水平,推测LCP的降压机理可能是降低了RAS系统的活化程度;此外,LCP显著降低了血液中脂多糖(LPS)的水平(P<0.05),并显著改善了肠道上皮结构的完整性。

To investigate the effect of LCP on blood pressure of SHR,LC with a low molecular weight of about 3.5 kDa was prepared by combining enzymatic hydrolysis and alcohol precipitation when takingκ-carrageenan powder as mate-rial.Mixed LC with the KCl solution,and the free potassium ion is removed by alcohol precipitation to obtain the LCP with high binding rate.The content of potassium bounded in LC increased from 6.5%to 8.7%.The experimental group was administered with 600 mg/kg of LCP.The negative control group was administered with distilled water.The positive control group was administered with 10 mg/kg of captopril.The results showed that LCP had a stable and sustained an-tihypertensive effect on SHR,and significantly reduced blood pressure by 18 mmHg compared with the negative group.LCP significantly reduced the levels of renin(P<0.05)and angiotensin II(Ang II)(P<0.01)in the RAS system.It is speculated that the antihypertensive mechanism of LCP may be to reduce the activation degree of RAS system.The level of lipopolysaccharide(LPS)in the blood was reduced(P<0.05)and the integrity of the intestinal epithelial struc-ture was significantly improved.This result will provide a scientific basis for further evaluation of the efficacy of carra-geenan oligosaccharides and the development of related products.