| Hypertension is a kind of worldwild common cardiovascular disease. in China, there are over 10% hypertension patients now. More serious, more and more people are threatened by hypertension. Thus, hypertension must be solved immediately. A lot of scholars devote themselves to the research on hypertension, but the cause of hypertension is not carified yet. Most of scholors agree on the standpoint that heredity and environment are the key factors to result in hypertension. In 1980's, professor Reaven put forward the theory of insulin resistance syndrome. Since then, researchers on hypertension had new thought and a large quantity of scholars began to study on the relationship between hypertension and insulin resistance syndrome. Now, they have attained content achievement and set up firmly foundation for applying insulin sensitizing agents to treat hypertension. The better drugs to lower blood pressure should be control blood pressure effective. In the same time, they could protect the organs function such as heart, kidney and cerebrum, which are harmed by long terms hypertensive situation. At present, the principal drugs that lower blood pressure such as Diurtic, beta-adrenoceptor blockers and calcium channel blockers can only control blood pressure on a certain degree. For some special hypertension patients, especially the patients with metabolism disease, these drugs can't lower their high blood pressure to normal level. The main cause is that we can't understand the etiology and pathogenesis of hypertension now. Some scholors deem that the principal cause is insulin resistance. Then, to treat hypertension through regulating body insulin sensitivity is a practicable road. There are a few of reports about insulin sensitizing agents to lower blood pressure, but the study on heart protection of insulin sensitizing agents are seldom. Enlightened by professor Reaven's theory, we select spontaneously hypertensive rats to exploit the possibility of applying Rosiglitazone to treat hypertension. Methods We select thirty-six male spontaneously hypertensive rats, they are seven or eight weeks age. All rats are divided into three groups at randomly: SHR groups, Rosiglitazone groups and Nifedipine groups. Nifedipine is the positive contrast drugs. All drugs are resolved to water to the rats. The whole experiment continues eight weeks. During the experiment, we take every rat's blood pressure one time per week. In the end of the experiment, we anesthetize the rats and put out their heats which are made into samples, we apply light and electron microscope to observe the rats'heart histopathology changes. Results After therapy of Rosiglitazone and Nifedipine, the rat's bloodpressure are lowered since the second week of the experiment, the average lowering level reach 20-25mmHg. At the forth week, Rosiglitazone and Nifedipine lower the blood pressure at the same level till the experiment end. From blood pressure curve graph, Rosiglitazone's function of lowering blood pressure is more steady in contrast to Nifedipine. The results of light and electro microscope show that the rats'myocardiums without drugs emerge collagen proliferation among the myofibrillar. Some myofibriller turn up loss near A and Z zone area. Mitochondrin are swelling and sarcoplasmic show dilatation situation. With treatment of Rosiglitazone and Nifedipine, there are little of collagen inside the myofibriller. The myofibriller structure appears normal without loss and disarrangement. Mitochondrin as well as sarcoplasmic show almost normal ultrastructure. Conclusion By the time of week 16, the rats show some histopathologic change on the hearts, such as collagen proliferation among the myofibriller, some moyfibriller turn up loss, mitochondrin are swelling and sarcoplasmic show dilatation. These changes are signs of heart damaged by hypertension. After therapy of Rosiglitazone and Nifedipine, collagen inside myofibrillar are hardly observed, the harmed myocardium ultrastucture turn out to be normal. The result demonstrates that Rosiglitazone and Nifeidipine can restrain collagen... |
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