The Cardio-protective Effect And GLP-1Regulation Of Jiangtangsanhuang Tablet In The Experimental Diabetic Rats

Part One Literature researchDiabetes is closely related to cardiovascular disease. Diabetic patiens are more likely to suffer from coronary atherosclerosis, heart disease, heart failure, atherosclerosis, hypertension and other cardiovascular diseases. Diabetic cardiopathy (DC) is a decline in heart function associated with diabetes, is one of the leading cause of mortality within the diabetic population. Diabetic cardiomyopathy is one of its types. The pathogenic performance mainly exists in the heart capillaries, cardiac muscle metabolism and fibrosis. Therefore, early prevention is the key of DC treatment.The pathogenesis of DC is very complex, may involve many factors such as myocardial metabolic abnormalities, myocardial fibrosis, autonomic neuropathy, stem cells, etc. DC is characterized by reduced myocardial compliance and diastolic filling blocked in the presence of a diastolic dysfunction as early clinical manifestations, followed by systolic dysfunction in later period which can lead to heart failure or arrhythmia. At present, there is not a single clinically effective treatment for DC. Once diastolic dysfunction has occurred, DC should be treated as soon as possible. Controlling blood glucose, blood pressure and blood lipids, preventing atherosclerosis, reducing cardiac stress are the prevention and treatment important steps of DC.Recent studies found that glucagon-like-peptide-1(GLP-1) and its analogs may have cardiovascular protective effects, especially for the cardiovascular system in patients with type2diabetes, what makes it become the focus of attention. GLP-1is an incretin hormone secreted by intestinal L cells, has glucose concentration-dependent of the hypoglycemic effect, that stimulates insulin secretion and protects β-cells, inhibits glucagon secretion and gadtric emptying, andreduces appetite and food intake. Recently, its analogs have been used for the treatment of type2diabetes.In Traditional Chinese Medicine(TCM) theory, diabetic cardiomyopathy belong to the scope of "XiaoKe","heart palpitations","chestpain", etc., Modern Chinese Medicine named it "Xiao Ke Heart Disease". Through the collation of ancient literatures, the pathogenesis of this disease is summarized to the weak endowment, improper diet, over clothing bladder stone, emotional disorders, and excessive works. There are many different points of view about pathogenesis of this disease, that can be broadly summarized as: Yin hot theory, deficiency of kidney theory, fiery theory, deficiency of Qi theory, the spleen and stomach theory, stasis theory, emotions pathogenic theory. TCM Diabetes Prevention Guide consider that DC is caused by deficiency of Qi, Xue, Yin, Yang as the primary causes, and Qi stagnation, phlegm, blood stasis coagulated cold as the secondary causes. The guide put DC into6syndromes:syndrome of deficiency both Qi and Yin, syndrome of blockade of phlegm-turbidity, syndrome of blood stasis blocking heart vessel, syndrome of deficiency both Yin and Yang, syndrome of Yang deficiency of heart and kidney, syndrome of pathogenic water attacking heart. But in general, the disease can not be separated from "stasis" of blood stasis, therefore, nowadays it become the main research direction of prevention and treatment of diabetic cardiopathy. Chinese medicine has broad prospects for research on the prevention and treatment of this disease."Relevance of Heart and Stomach" theory is generated on the basis of the "Five Visceras" theory of Professor Deng Tietao. The concept of the stomach in traditional chinese medicine includes small and large intestine."Relevance of Heart and Stomach" theory is based on the meridian relations between heart and stomach, and relationship between mother and child according to the Five Elements theory. Recent researches had also proved that the physiological between heart and gastrointestine are related each other, so as their pathology which affecting each other. Therefore, as the main threat to diabetic cardiopathy, the treatment for heart disease can also adopt the idea of "heart disease take the cure from stomach".The first affiliated hospital of Guangzhou University of Traditional Chinese Medicine Xiongmanqi’s research team invented Chinese patent drug-Jiangtangsanhuang Tablet in the1980’s, originating from Taohe chengqi decoction from Shanghan Lun, based on the the pathogenesis of deficiency in qi and yin, stagnation of blood stasis, with tonificating qi and yin, also eliminating stagnation of blood stasis as the therapeutic method. Many clinical and mechanism studies founded that Jiangtangsanhuang tablet has a cardioprotective effect. Based on the former research, these literature and experiments are meant to explore the cardioprotective effect of JTSH to further prove "Relevance of Heart and Stomach" theoretical science.Part Two experimental researchObjective:To observe the cardio-protective effect and the expression of GLP-1of JTSH tablet against the experimental diabetic cardiopathy rats,to reveal the "relevance of heart and stomach" theory.Methods:Healthy SD rats were randomly divided into normal group(n=9) with regular feed and diabetic model group with high cholesterol diet (HCD) throughout the study period. The model group induced by low-dosage streptozocin (STZ)(40mg/kg) after2weeks of HCD and were randomly divided into four group with fasting blood glucose>11.1mmol/L:model group, high-dose of JTSH group (787.5mg/kg/d), low-dose of JTSH group (393.75mg/kg/d), metformin group (52.5mg/kg/d), DPP-4inhibitor group (10.5mg/kg/d),7rats each group. After5weeks treatment, acute myocardial ischemia model were established on all groups induced by Pituitrin injection.①The general status (food and water intake, excretion) were measured everyday, body weight and fasting blood glucose were measured every week during the treatment. The glycosylated hemoglobin were measured after acute myocardial ischemia model were established.②GLP-1amide in plasma were measured using ELISA. The large intestine and hypothalamic were detected for the expression of GLP-1mRNA Real Time PCR.③The myocardial tissue pathological changes were observed by optics microscope and ischemia area were measured by Image-Proα Express5.1.Results:1. After modeling, polydipsia, polyphagia, polyuria and weight loss symptoms appear on model group; their water intake, food intake, excretion and fasting blood glucose were significantly higher than normal group, indicates that diabetic modeling was succeed. After5weeks treatment, JTSH can improve the symptomps of polydipsia(P<0.05or P<0.01), but can’t yet improve the symptoms of polyphagia. The excretion of JTSH both high-dose and low-dose are more than before treatment, which is the effect of JTSH. JTSH also can increase the body weight of diabetic rats and reduced their blood glucose significantly (P<0.05or P<0.01). However, HbAlC level on high and low-dose of JTSH groups were not significantly lower than model groups, probably due to shorter experimental period. DPP-4inhibitor group has the best effect of glycemic control, followed by metformin group, high-dose of JTSH group and low-dose of JTSH group respectively.2. GLP-1amide in plasma were measured using ELISA. The large intestine and hypothalamic were detected for the expression of GLP-1mRNA Real Time PCR. The result indicated that the GLP-1amide in plasma on high and low-dose of JTSH group were higher than the model group, the metformin group and the DPP-4inhibitor group, but it hadn’t statistically significance. In high-dose of JTSH group, the expression of GLP-1mRNA on its large intestine were2.48times higher than the model group (P>0.05), while the expression of GLP-1mRNA on its hypothalamic were6.46times higher than the model group(P<0.05); in low-dose of JTSH group, the expression of GLP-1mRNA on its large intestine were1.14times higher than the model group(P>0.05), while the expression of GLP-1mRNA on its hypothalamic were2.87times higher than the model group(P>0.05). But still, GLP-1mRNA expression level on JTSH groups were lower than the metformin group and the DPP-4inhibitor group. These results indicated that JTSH has a certain role in improving GLP-1, by directly effecting on the gene.3. The myocardial tissue pathological changes were observed by optics microscope and ischemia area were measured by Image-Proα Express5.1. Pathological changes such as focal myocardial cell degeneration or necrosis, eosinophilic cytoplasm stained, stripes unclear, karyopyknosis or nucleus disappear, gap increases between myocardial cells, interstitial scattered infiltration of inflammatory cells, but no fibrosis, could be found at myocardial ischemia area of all rats in low-dose of JTSH group. While similar pathological changes could also be found at6rats in high-dose of JTSH group, but there was1rat which its myocardial tissue was no obvious degeneration nor necrosis, no interstitial hemorrhage nor edema, no inflammatory cell infiltration nor fibrosis. The result indicated that the ischemia area of high and low-dose of JTSH group were smaller than the model group, but bigger than the metformin group and the DPP-4inhibitor group.Conclusion:1. Jiangtangsanhuang Tablet can improve glucose metabolism, elevate GLP-1in amide plasma and its mRNA expression in large intestine and hypothalamic. But the efficacy of metformin and DPP-4inhibitor were better than JTSH tablet.2. The cardio-protective effect and the GLP-1expressions at high-dose of JTSH group were more obvious than low-dose of JTSH group.