The Changes Of VR1 & SP In Myocardium Of Diabetic Rats

The incidence of diabetes mellitus is becoming progressively more frequent and the basic pathology of diabetes mellitus is diabetic neuropathy. This is responsible for coronary atherosclerotic heart disease. Therefore we need to know the mechanism of diabetes vascular complication in details. As we know multiplicity sensory nerve terminal exsit all over the heart not only cardiac pericardium but also myocardium and papillary muscles. It already known that VR1, as an iron channal on sensory nerves, can be stimulated by lots stimulies such as capsaicin and many protons. VR1 receptor's activation can cause neurotranmitters such as CGRP(calcitonin gene-related peptide) and SP (substance P) release resulting in vasodilatation and bradycardia.Recently,many researches show that there is more severe myocardial infarction in diabetic mice than in non-diabetic mice. One of the most important complications of diabetes mellitus is diabetic neuropathy which induces abnormality of cutaneous sensation, gastrointestinal and cardiovascular system. Therfore, we can suppose that deficience of VR1 receptors and/or neurotranmitters such as CGRP and SP in diabetic patients cause their weakness of self-protection in myocardial infarction.Objectives1. How about the changes on VR1 receptor and SP in diabetic rate's sensory nerve terminal under western blot an RI.2. Whether VR1 receptor and SP can protect heart from myocardial infarction.Experimental Animals1. model of type II diatetic ratsSixteen C57BL6 male rats were divided into 2 grups randomly. Group A were given high fat diet while the other group were given normal diet. At the end of the fourth week, Group A were given STZ by intraperitoneal injection. Keep feeding for another 3 weeks.2. Detect VR1 through western blot.2.1 Prepare the fluids using in Western blot.2.2 Get each heart of grups A and B about 50mg, homogenating each tissue with 50ml schizolysis solution. Store the samples under -80℃.2.3 Detect the protein concentration: detect each sample's A₅₉₅ according to Bradford and get the concentration of the samples using the standard proteinum curve.2.4 Polyacrylamide gel electrophoresis: using 10% separating gel and substrating gel.2.5 Western blot: trarsmembrane; blockage; incubation with Ab-1 and Ab-2; visualization; analysis the blotting.3 Dtect S.P through RIA3.1 Prepare IN glacial acetic acid and IN NaOH。3.2 Get each heart of grups A and B for 50mg, homogenating each tissue with glacial acetic acid and 1N NaOH. Store the samples under -20℃ after centrifugalization.3.3 Dtect S.PDepartment of ECT helped detecting S.P.3.4. AnalysisStatistical analysisExperimental values were expressed as means±SD, Analysis of variance was done by SPSS10.0 for window One-Way ANOVA and those less than 5% (P<0.05) were considered significant, those less than 1% (P<0.01) were considered very significant.Results1. Through high-fat diet and intraperitoneal injection of STZ, the blood sugar of the experimental groups were all over 16.7mmol/l, consistenting with the standard of type-2 diabetic rats model, which was significant between the control groups (P<0.001).2. The concentration of VR1 receptors in groups of diabetic rats was lower than that of the groups of normal, which was significant between the normal groups (P<0.001).3. The concentration of SP in groups of diabetic rats was lower than that of the groups of normal, which was significant between the normal groups (P<0.01).Conclusion1. Diabetes mellidus cause severe neuropathy in rats's hearts and it reduces the quantity of VR1 receptor which is with responsibility for the susceptivity of myocardiol infarction.2. Diabetes mellidus cause severe neuropathy in rats's hearts and it reduces the quantity of SP because of the decrease of VR1 which shows protection during myocardiol infarction.