Expression of calcium-sensing receptor in the progress of myocardial injury induced by doxorubicin in rats

Objective To detect the expression of calcium-sensing receptor(CaSR) during development of myocardial injury,to provide new ideas for the role of CaSR in the process of myocardial injury induced by doxorubicin.Methods Forty male Wistar rats were randomly divided into two groups: control group(n=10) and injury group(n=30).The injury group rats were randomly divided into 3 weeks group,6 weeks group,and 9 weeks group.Myocardial injury was induced by intraperitoneal injection of doxorubicin(2.5 mg·kg-1·w-1).Left ventricular internal diameter and the cardiac function of the rats in each group were detect by echocardiography.The myocardial histologic structural changes were observed under the microscope after HE staining.Futher more the expression of CaSR was analyzed by Western blot and immunohistochemistry.Results The left ventricular end diastolic diameter(LVDD) was increased obviously in 9 weeks group compared with control group(P0.05),and the left ventricular ejection fraction(LVEF) reduced significantly(P0.01).HE staining showed that the cellular morphology of the control group was normal,while the cell swell,cytoplasm loose and lightly stained,eosinophilic enhanced,nuclei enlarged,unclear stripes and vacuolar degeneration in the myocardial injury group.The quantitative expression of CaSR was significantly decreased in the first three weeks after treatment of doxorubicin while increased at 9 weeks(P0.01),There was no significant difference between the group of 3 weeks and 6 weeks.Conclusion The change in expression of CaSR during the process of myocardial injury is firstly decrease and then increase,which may provide a new treatment for the myocardial injury induced by doxorubicin.The change of CaSR may play an important role in determining the severity of myocardial injury and heart function.