| Viral myocarditis (VMC) is one of the common cardiovascular diseases with variant clinical manifestations in pediatrics. During the acute period of the disease, some patients may have no clinical manifestations, while others may show the heart failure, cardiogenetic shock, ventricular tachycardia and even sudden cardiac death. Furthermore, some VMC ultimately leads to dilated cardiomyopathy which severely threatens the health of the patients. Since 1970's,with the increased occurrence of VMC, the animal and cell models of VMC induced by Coxsackieviruses group B (CVB) have been established. Though it has been explored in the aspects of immunologic reaction, apoptosis, etc, the pathogenetic mechanism of VMC still remains uncertain. Therefore, exploring the pathogenetic mechanism may contribute to the clinical treatment on the cardiovascular diseases.The pathogenetic mechanism of VMC is very complicated. Previous studies supported that the killing effects of the virus and the immunologic reaction to the virus were involved in the mechanism. Recent researches showed that the effect of virus to the ion channels maybe takes part in and /or aggravates the cardiac cell damage caused by the virus. However, the exact mechanism is still not well known. The potassium channels are the most important ion channels with the genetic andfunctional varieties. They control the resting membrane potentials, the amplitudes and the durations of the action potential, refractoriness, and the automaticity. Recently, it is demonstrated that the mRNA levels of the potassium channels of the cardiac cells are changed in the common diseases such as heart infarction, chronic heart failure, hypertension, et al. But it is not indicated whether the ion channels are changed in virus-infected myocardiocytes.It is the focus of the researchers' to find effective drugs to treat the viral myocarditis. Many data manifested that many Chinese herbs are useful to treat the VMC, especially in chronic period. Nowadays, many results show that Rutin can inhabit the lipid oxydase, keep the integrality of the myocardiocytic membrane to protect cardiac cells from the oxygen-deficience and ischemia-reperfusion injuries. However, there is no report about whether Rutin plays the protective effect in virus-infected myocardiocytes and its related mechanism.In our research, we cultured the newborn SD rats' ventricular cells, then established the virus-infected cell model, and treated it with Rutin. We observed the morphological change, measured the K+ level in the supernatant and the mRNA changes of the voltage-gated potassium channel Kvl.2, Kvl.5, Kv2.1 and Kv4.2 gene transcriptions and, Kvl.5 and Kv4.2 protein expressions. The purpose of this research is to find the changes of the voltage-gated potassium channels and the effects of Rutin on the virus-infected cardiac cells and its related mechanism.Part I The culture of the newborn SD rat ventricular cells and the establishment of the virus-infected cell modelThe newborn SD rat ventricular cells were isolated by digesting with 0.1% trypsin solution at 37C repeatedly . To purify the myocardiocytes, we precultured the cells for about 2 hours and used the O.lmMBrdU in the first 3 days. Forty eight hours after culturing, we divided the cells into 2 groups: the control group and the virus-infected group. We added the 200TCID50CVB3m to the infected group, after 2hours' incubation, we washed the cells with Hank's solution and then added the RPMI solution to the cells. We changed the solution every 2 or 3 days, observed the cells and measured the levels of AST, CK-MB and LDH in supernatant at 24-hour, 72-hour and 120-hour points after viral infection.Results:1. The observation of the cells: After 24 hours culturing, all cells attached to the culture surface. The cells presented spindle or rod shape, with few bifurcates, and began to beat slowly and weakly. At this time, the cells were not totally fixed together. After 48 hours' culturing, the cells had more bifurcates, and fixed to be chrysan... |
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