Antihypertensive Effect Of Enzymolysis Liquid Of Chinese Wolfberry Protein On Spontaneously Hypertensive Rats

Objective: Hypertension is one of the most important risk factors of cardiovascular disease. The control of hypertension is an effective measure to reduce the rates of suffering, disability and death of cardiovascular disease. Angiotensin converting enzyme(ACE) inhibitory peptides regulated blood pressure by impacting the renin-angiotensin system and kallikrein kinin system. Angiotensin-converting enzyme(ACE) inhibitors are very important drugs for clinical treatment of hypertension. Food Protein-derived ACE inhibition peptides have been paid considerable attention in recent years beeause of theirs light side effects,higher safety and absortion. In this experiment, the protein was extracted by alkali extraction and acid precipitation method, and the results were obtained by the method of protease decomposition. To observe the antihypertensive effect on spontaneously hypertensive rats, and to provide theoretical basis for the preparation of ACE inhibitory peptides and clinical control of hypertension.Methods: 40 male SHR rats and 8 WKY which were about 10- 11 weeks old and 240-280 g of weight,were entrained to free access to food and tap water for one week. Depending on blood pressure and weight, they were divided randomly according to random number for 6 groups(n = 8), respectively: WKY control group, positive control group, negative control group, low dose group(Lycium barbarum hydrolysate 40 mg / kg), middle dose group(Lycium barbarum hydrolysate 80 mg / kg) and high dose group(Lycium barbarum hydrolysate 100 mg / kg). During the experiment, experimental group was administered by given differentconcentrations of Lycium barbarum protease solution, negative control group and WKY normal control group were administered with distilled water, positive control group were given captopril 10 mg / kg. Rats were fed 1 times a day, and the experimental period was 9W. During the experimental period, the animals were free to eat and drink. Measurement of SBP, DBP and heart rate was used noninvasive tail cuff experimental system at fixed times per week, blood pressure was measured3 times. The blood pressure in each group was compared, and there hair color, irritability,water content and so on were observed. The contents of Angll in plasma were detected by ELISA, the m RNA expression of ACE,AT1 R, ACE2 and Mas R in heart and kidney were analyzed by Real-time PCR.Results:(1) The behavior of the rat: During the experiment, rats of WKY group had shiny hair, flexible eyes, quick action; SHR rats had volumed hair, excessive drinking water and aggression. The mental state of SHR rats had improved, and the hair was gradually shiny after two weeks of treatment.(2) Feed intake, weight and heart rate change: SHR rats were significantly higher than WKY(P < 0.05), but there was no significant difference in the amount of food between SHR rats(P > 0.05). Before the experiment, there was no significant difference between all groups(P > 0.05). At the end of the experiment, compared with WKY, the weight of SHR rats was significantly decreased(P < 0.05), but there was no significant difference in heart rate between the groups(P > 0.05).(3) The rat organ weight and organ coefficient: Compared with the WKY group, cardiac coefficient, kidney coefficient, liver coefficient of SHR rats were significantly increased(P < 0.05); but lung coefficient and spleen coefficient was no significant difference(P > 0.05).(4) Antihypertensive effect of enzymolysis liquid of Chinese wolfberry protein on SHR: At the beginning of the experiment, blood pressure in SHR rats were significantlyhigher than those in WKY group(P < 0.05), but between SHR rats there was no significant difference(P > 0.05). At the end of the experiment, compared with the negative control group, positive control group, low dose group, middle dose group and high dose group, blood pressure were significantly decreased.(5) The contents of Ang II in plasma:Compared with the WKY group, Ang II levels of negative control group and high dose group were significantly increased; compared with the negative control group, Ang II content of low dose group and positive control group were significantly decreased(P < 0.05); Ang II content of middle and high dose group had no significant difference(P > 0.05).(6) The m RNA expression of ACE, AT1 R, ACE2 and Mas R in heart and kidney:Compared with WKY group(1.000±0.085),negative control group(2.624±0.631), ACEm RNA expression of middle dose group(2.287±1.716) and high dose group(2.396±0.632) in kidney were significantly increased(P<0.05); compared with the negative control group(2.624±0.631), ACEm RNA expression of positive control group(1.230±0.540) and low dose group(1.260±0.643) were significantly decreased(P<0.05); compared with WKY group, the expression of ACE2 m RNA were significantly decreased in SHR kidney(P<0.05), compared with the negative control group(0.427±0.085), ACE2 m RNA expression of positive control group(0.659±0.134) and low dose group(0.601±0.134) were significantly increased(P<0.05); the expression of ATIR receptor m RNA, Mas receptor m RNA were no significant difference(P > 0.05).Conclusion: 1. Enzymolysis liquid of Chinese wolfberry protein has certain antihypertensive effect on SHR. 2. The antihypertensive effect had achieved maybe through regulating the balance of ACE-Ang II-AT1 pathway and ACE2-Ang(1-7)-Mas pathway.