糖尿病大鼠心肌磷酸受纳蛋白基因表达和肌浆网Ca(上标 2+)-ATPase活性的变化

AIM: To investigate the alterations of phospholamban (PLB) expression and cardiac sarcoplasmic reticulum (SR) Ca(superscript 2+)-ATPase activity, and the change of cardiac function in rats with diabetes mellitus (DM). METHODS: The diabetes mellitus in male Wistar rats was induced by intraperitoneal injection of streptozotocin. The levels of PLB mRNA and PLB protein, the activity of SR Ca(superscript 2+)-ATPase and the left ventricular hemodynamics parameters were measured 4 weeks, 6 weeks and 8 weeks after DM was induced in rats, while the normal rats served as control group. RESULTS: There was no significant difference in PLB mRNA level and protein level between 4-week-DM rats and normal control rats. 6-week-DM rats and 8-week-DM rats had markedly increased PLB mRNA and protein level compared with normal control rats. SR Ca(superscript 2+)-ATPase activity was not significantly changed in 4-week-DM rats compared with normal control rats, and was markedly depressed in 6-week-DM rats and 8-week-DM rats. LVSP, LVEDP and ±dp/dt(subscript max) were not significantly changed in 4-week-DM rats compared with normal control rats. In 6-week-DM rats and 8-week-DM rats, LVSP and ±dP/dt(subscript max) were decreased, LVEDP was increased compared with normal control rats. CONCLUSION: The elevated levels of PLB mRNA and PLB protein contribute t) SR Ca(superscript 2+)-ATPase activity reduction, which leads to cardiac dysfunction in DM rats.