Experimental Study Of Estrogen And Puerarin In Preventing And Curing Rat Hyperhomocysteinemia

High levels of homocysteine are recognized as an independent risk factor for the development of atherosclerosis and cardiovascular diseases. Hyperhomocysteinemia is associated with myocardial infarction, coronary artery disease and peripheral vascular disease. Its pathomechanism, which includes the damaging of the endothelial function, is very complicated;therefore, how to reduce the level of homocysteine and to lower its damaging effects are becoming hot spots for research recently. Oral administration of folic acid and vitamin B₁₂ can reduce the level of homocysteine, and as some research have reported, estrogen replacement therapy could also obtain similar effects. However, there are only a few studies on the role of estrogen in decreasing hyperhomocysteinemia. Some researchers have reported on the relationship between estrogen and homocysteine but it is not yet conclusive. By means of molecular biology methods and animal experiments, this article focuses on the protective function of estrogen on the damage resulted from hyperhomocysteinemia. Because puerarin has similar functions as that of estrogen, we built animal models of hyperhomocysteinemia to check the differences between estrogen and puerarin.Objective:1.To estabilish animal models of hyperhomocystein-emia. 2. To observe the effects of estrogen and puerarin on level of homocysteine AngII ET in animal model' s plasma. 3. To observe the effects of estrogen and puerarin on levels of myocardial AngII AT₁R mRNA AT₂R mRNA, ET, NO NOS mRNA in animal model. 4. To observe the effects of estrogen and puerarin on levels of myocardial ERα mRNA and ERβ mRNA in animal model.Method: 44 wister female rats were divided into 6 groups: (1) estrogen was added during building the models (n=8);(2) puerarin was added during building the models (n=8);(3) estrogen was added after building the models(n=8);(4) puerarin was added after building the models (n=8);(5)Control group (n=6);(6)Model group (n=6) . Oophorectomy was performed on all rats to prevent the production of estrogen, then the model group was given a diet containing high levels of methionine to build rat models of hyperhomocysteinemia without any interference. The first group and the second group were called prevention group, the third and fourth ones were called treatment group. In the first section, after having been fed for 6 weeks, the level of homocysteine was checked in the model and the control group. After been fed for 75 days, the level of Hcy> Angll and ET in plasma were checked in all the groups.In the second section, myocardium Angll and its receptors mRNA levels were compared. In the third section, myocardium N(k NOS mRNA> ET levels were compared. In the last section, estrogen receptor ER a mRNA and ERJ3 mRNA were compared.Results: In the first part, compared to the control group, the level of Hey in the model group is higher, which demonstrates the successful establishment of hyperhomocysteinemia in rat models. The level of plasma Angll in model group is also higher, while there is no difference in the level of ET. Plasma Hey and Angll concentration are lower in prevention groups than in model group. Plasma Hey concentration is lower in treatment group with puerarin while Plasma Angll concentration is lower in treatment group with estrogen. Plasma ET concentration is lower in prevention group with puerarin. In the second part, there is no difference in myocardial Angll concentration in model group and control group, but compared to the control group, it is lower in prevention and treatment group. In the model group, the expression of ATI mRNA is higher than in the control group, compared to the model group, only treatment group with puerarin has lower level while others havedescending tendency although there is no statistical difference. The expression of AT2 mRNA doesn' t have distinction among any group, with ascending tendency in disposal group. In the third part, compared to the control group, NO concentration and the expression of NOS mRNA in model group have no difference;however, the myocardial ET concentration is higher in model group while the myocardial NO concentration is higher in prevention group with puerarin. The expression of NOS mRNA is higher in prevention group and treatment group with puerarin. The ET concentration in both prevention group and treatment group is depressed. In the last part, there were no significant difference in ERa mRNA and ERï¿¡ mRNA between model group and control group;however, the myocardial ERa mRNA is higher in prevention groups, while the myocardial ER3 mRNA expression is increased in prevention group with puerarin.Conclusions: (1)A diet of high methionine content for 6 weeks can cause hyperhomocysteinemia. Both estrogen and puerarin can decrease the level of plasma Hey. Hyperhomocysteinemia can result in higher level of plasma Angll, indicating thathyperhomocysteinemia may damage the endothelial function through circulation RAS, estrogen and puerarin both can prevent ascending plasma Angll, and at the same time, estrogen can depress its concentration. ET level is not increased by hyperhomocysteinemia, but puerarin and estrogen could down-regulate the ET level in plasma. (2) Hyperhomocysteinemia is not found to impact myocardial Angll or AT2 mRNA, but can up-regulate the expression of myocardial ATI mRNA, both drugs can down-regulate myocardial Angll while only puerarin can inhibit the expression of ATi mRNA. We suppose that hyperhomocysteinemia can influence tissue RAS by increasing Angll receptors. Estrogen and puerarin can protect myocardium through decreasing Angll and ATi mRNA. (3) Hyperhomocysteinemia is not found to affect myocardial NO and eNOS mRNA but can increase the expression of ET. Estrogen and puerarin can up-regulate myocardial eNOS mRNA to protect model' s myocardium. (4)There is no significant impact on myocardial ER with high level of Hey. However, the two drugs both can up-regulate the expression of ERa mRNA while puerarin can increase ER0 mRNA to protect model' s hearts.