Effects Of Eukaryotic Expression Vector PcDNA3.1 Mediated C-reactive Protein Gene On Blood Pressure In Sprague-Dawley Rats

Objective Hypertensive patients often have the character of chronic inflammation, however, the relation between chronic inflammation and hypertension is far from clarified. Whether chronic inflammation may be an inducible factor in the pathogenesis of hypertension is needed to be explored. In this study, we used the models of chronic inflammation induced by lipopolysaccharide, and explored the effects of chronic inflammation on blood pressure and its possible mechanisms.Methods Eighteen female Sprague-Dawley rats were divided randomly into three groups, and each group had six rats. One group was control group, and different concentration of 0.9% Sodium Chloride and lipopolysaccharide were injected intraperitoneally by some interval, the caudal arterial pressure was measured regularly. One month after the injections of 0.9% Sodium Chloride and lipopolysaccharide, all of the rats were sacrificed. The parameters of heart haemodynamics were measured by PowerLab 4/20 polygraphy , before all the rats were sacrificed. thoracic aorta was cut into several vascular rings, and blood vessel tones were measured by RM6240C polygraphy.The dose-effects curve of acetylcholine was made in the following ways: 1.0×10-6mol/L norepinephrine was added into K's solution to stimulate the contraction of vascular ring. Different concentration acetylcholine was added into K's solution after the vascular tone was stable, then curve measured was dose-effects curve of acetylcholine. The analyses of pathological tissue morphology: the sections of pathological tissue were analyzed by HE staining.Results The blood pressure of rats began to increase gradually ten days after the injection of different concentration of lipopolysaccharide. The blood pressure of rats kept increasing until 30 days fter the injection of lipopolysaccharide. Compared with the group of 0.9% Sodium Chloride, the heart rate and LVDP increased significantly, and the LVSP and±dp/dtmax decreased significantly in the group of LPS 5mg/kg.Compared with control group, the effects of acetylcholine to stimulate vascular rings relaxation in the groups of LPS 5mg/kg decreased, significantly especially in the concentration dots of acetylcholine10-6,10-5,10-4,10-3mol/L. In the groups of LPS 5mg/kg and LPS 10mg/kg, part of myocardial myofilaments were of disorder arrangement, split and part of cardiac muscle cells were hypertrophy. Compare with control group, tunica media was mildly thickening and of disorder arrangement In the groups of LPS 5mg/kg and LPS 10mg/kg.Conclusions Compared with control group, blood pressure increased significantly, the systolic and diastolic functions decreased significantly, the diastolic function of thoracic aorta decreased significantly , and cardiac remodeling appeared in the group of lipopolysaccharide. Chronic inflammation may associate with hypertension.