Effects Of Several Plant Proteins On Lipid Metabolism And Related Gene Expression In Rats

In the past few decades, modern medicine for pathogens clearer diseases have made good progress, but for the pathogen is not yet clear disease, including cancer, cardiovascular and other chronic diseases, progress is very disappointing. Along with the increase in population of chronic diseases, the expansion of the medical expenses are gradually sparked a global "health crisis", it forces us to rethink the medicine development strategy, from "for the purpose of disease treatment" to "for the purpose of disease prevention" development strategy, mode shift from the treatment of chronic diseases to chronic disease prevention, perhaps can relieve the social and economic pressure brought by chronic diseases. Above several proteins are main source of protein for the present stage our country residents daily meals, study of the role of different sources of dietary protein in the blood Hpid regulation on by adjusting the diet to prevent chronic disease has a certain significance.Abnormal blood lipid is a common characteristic and risk factor of chronic diseases, more and more studies focus on improving the body lipid metabolism through diet control, and except to find the influence of food or nutrients to the body fat. Back in the 1980s,studies have found that compared with casein, soy protein can decrease serum triglyceride and cholesterol levels, the research open the door of revelation between protein and lipid metabolism. Most of the research after that, have showed the same results. In addition, soy protein amino acid balance and high digestibility, accord with human body needs, is recommended for high quality protein. For many years, the studies of protein in blood lipid regulation mostly use soy protein as the research object, lack of a certain new idea.Rice is China’s first major grain crops, Chinese Residents’Dietary Guidelines suggest that we should intake of grains, potato and beans 250-400 grams, According to our resident’s eating habits, we can presumably that the intake of rice occupy a great proportion. In addition, the grain is considered to lack of lysine, so recommended intake of soy protein at the same time, in order to play a complementary role in protein, but there is also a lack of studies of rice protein and dietary protein complementary impact on lipid metabolism. Casein is mainly present in the milk of mammals, now our country residents drinking milk is increased, the intake of casein also will increase. Due to above consideration, this experiment closely with residents’eating habits, select casein and soy protein, rice protein, soy and rice mix protein, integration the above protein in animal experiment, in order to draw the role of proteins in lipid metabolism; And by detecting the expression of related genes in rats, in order to have a simple analysis of the mechanism of action. All these are except to useful for the use of dietary protein regulation of lipid metabolism.MethodsAfter adaptability a week,45 male Wister rats randomly divided into 5 groups, respectively:standard control group, casein group, soybean protein group, rice protein group, mixed protein group. Each group of 9 rats,3 rats a cage, each group of 3 cages. Standard control group feeding the AIN-93G standard diet, the rest of the four groups respectively feeding single sources of protein diet, respectively is:casein, soybean, rice protein, mixed protein(soybean protein, rice protein= 1:1).Experimental period for 6 weeks, free feeding, drink RO water, record food intake in rats everyday; and weight 1 times a week at fixed time (4 pm to 5pm); Determination of lipid levels of rats (TC, TG, HDL, LDL) every 2 weeks.6 week end, put to death, taking fresh liver tissue of rats to extract total RNA, real-time PCR assay genes expression in lipid metabolism, such as SREBF-1, FAS, PPARa, HMG-COA R, CYP7A1. Results 1. Animal blood lipid determination results (1) TC changes in ratsExperiments initially, each group TC level were balanced, there was no significant difference; The experiment 2 weeks, rice protein group TC levels first appeared declined significantly, compared with the rest of the group have significant difference; Experiment 4 weeks, soy protein and beans rice hybrid group TC levels also showed a trend of decline, but compared with casein group, does not have significant difference; For six weeks, soybean protein, rice protein group, and mixed group TC levels were significantly lower than that of casein group. During the experiment, the casein group TC level from two weeks was lower than the standard control group, but there was no significant difference.Visible, compared with casein, the level of the rest of the three proteins have lower TC, and rice protein have the fastest function. As the experimental period, the soybean protein and mixed protein have the same function. (2) TG changes in ratsExperiments initially, each group TG level were balanced, there was no significant difference; From the experiment 2 weeks, rice protein and mixed protein group TG levels have dropped significantly, compared with the rest of the three groups have significant difference; With the experiment 6 weeks, casein and soybean protein group there was no significant difference; Soybean protein, rice protein group, bean rice hybrid group there was no significant difference between the three groups; Two comparison between the rest of the group have significant difference.Visible, compared with casein, rice protein and mix proteins can significantly lower the blood TG level; The role of soybean protein lowered blood TG level is not significant; And between the three kinds of protein, soybean protein have the slowest speed of decrease TG level. (3) HDL changes in ratsExperiments initially, each group HDL level were balanced, there was no significant difference; From the experiment 2 weeks, rice protein group had a significantly lower than the rest of the four groups of HDL levels; Experiment 4 weeks, two comparison between five group were no significant difference; For six weeks, soy protein and rice protein group HDL levels significantly lower than the other three groups, there was no significant difference between the rest of the group.HDL levels in combination with the TC level analysis shows, compare with casein, rice protein and mixed protein can raise HDL effect of total proportion of TC, and mixed protein has the strongest function. (4) LDL changes in ratsExperiments initially, each group LDL level were balanced, there was no significant difference; Experiment 2,4 weeks, rice protein group had a significantly lower LDL than the rest of the four groups, and there was no significant difference between the rest of the compares. The experiment 6 week, rice protein group had a significantly lower LDL than the standard group and the casein group, there was no significant difference between the rest of the group.HDL levels in combination with the TC level analysis shows, Compared with casein, rice protein can significantly lower LDL levels; soybean protein group and mixed protein while significantly lower levels of TC, can lower LDL levels, but the effect is not significant. Moreover, compared with soybean protein and mixed protein, rice protein can lower LDL accounted for the proportion of the total TC.2. Animal blood lipid gene expression results(1) SREBF-1 mRNA relative expressionAt the end of the experiment, the standard control group and casein group SREBF-1 mRNA relative expression there was no significant difference. Compared with casein group, soybean protein, rice protein group, mixed protein group relative expression significant decline, and the difference is statistically significant; And the rice group has the lowest relative expression.Visible, compared with casein, three kinds of protein can inhibit the liver tissue SREBF-1 mRNA expression, and rice protein has the strongest function; soy protein and mixed protein have the closely effect.(2) FAS mRNA relative expressionAt the end of the experiment, the standard control relative group FAS mRNA expression is significantly higher than the rest of the group. Compared with casein group, rice protein group and mixed protein group FAS mRNA expression were significantly decreased; And rice protein group FAS mRNA expression was significantly lower than the rest of the group; Soybean protein FAS mRNA expression lower than casein group, but the difference is not significant.Visible, compared with casein, rice protein and mixed protein can inhibit the liver tissue FAS mRNA expression, and rice protein has the strong function; Soy protein also can inhibit FAS mRNA expression, but there is no significant difference.(3) PPARa mRNA relative expressionAt the end of the experiment, the standard control group PPARa mRNA relative expression is significantly lower than the rest of the group. Compared with casein group, soybean protein group and mixed protein group were significantly increased; and the expression in mixed group is significantly higher than that in other groups; Expression in Rice protein and casein group was no significant difference.Visible, compared with casein, soy protein and mixed protein can promote liver tissue PPARa mRNA expression and mixed protein has strongest function.(4) CYP7A1 mRNA relative expressionAt the end of the experiment, the standard control group CYP7A1 mRNA relative expression is significantly lower than the rest of the group. Compared with casein group, soybean protein group and mixed protein group were significantly increased; and the expression in mixed group is significantly higher than that in other groups; Expression in Rice protein and casein group was no significant difference.Visible, compared with casein, soy protein and mixed protein can promote liver tissue PPARa mRNA expression and mixed protein has strongest function.(5) HMG-COA R mRNA relative expressionAt the end of the experiment, the standard control group HMG-COA R mRNA relative expression is significantly lower than that in casein group. In addition, compared with casein group, soybean protein group, rice protein group and mixed protein group were significantly decreased; and the expression in rice protein group was significantly lower than other groups; Expression in soy protein group and mixed group was no significant difference.Visible, compared with casein, soybean protein, rice protein and mixed protein can inhibit HMG-COAR mRNA expression, and rice protein has the strongest function.Conclusion1. Compared with casein, soybean protein can significantly reduce the level of serum TC, but it reduce blood TG level is not significant. In terms of triglyceride metabolism, soybean protein can raise PPARa gene expression, promote the fatty acids in the beta oxidation, in order to reduce the serum TG level; In terms of cholesterol metabolism, soybean protein can inhibit the HMG-COA R gene expression and promote CYP7A1 gene expression, on the one hand inhibition of endogenous cholesterol synthesis, on the other hand promote the synthesis of bile acid, and speeding up the transformation of cholesterol, thus significantly lower serum TC level.2. Compared with casein, rice protein can decrease TC and TG levels, and can reduce serum LDL level, and the lower TC fastest. Also rice protein can increase HDL level account on the body. Rice protein can inhibit the HMG-COAR, SREBF-1, FAS gene expression, thus inhibiting endogenous cholesterol and fatty acid synthesis, to reduce serum levels of TC, TG, and rice protein in the inhibition of endogenous cholesterol and fatty acid synthesis are stronger than the effect of soybean protein and mixed protein;3. Compared with casein, mixed protein can decrease TC and TG levels, and can increase the serum HDL accounted for the proportion of the total TC, and the function is stronger than other proteins. In terms of triglyceride metabolism, mixed protein can inhibit SREBF-1, FAS gene expression, and promote PPARa gene expression, so as to reduce the synthesis of fatty acids on one hand, on the one hand promote the fatty acids in the beta oxidation, in order to reduce serum TG level. In terms of cholesterol metabolism, mixed protein by inhibiting the HMG-COA R gene expression, promote CYP7A1 gene expression, which on the one hand, reduce the endogenous cholesterol synthesis, on the other hand, promote transformation of cholesterol, so as to reducing serum TC level.