Distribution of ~(99m)Tc-AcTnI MA in rats with myocardial injury

Objective To study the distribution pattern of ~(99m)Tc-AcTnIMA in rats with experimental myocardial injury, thereby determining the possibilityof ~(99m)Tc-AcTnIMA to be a tracer of myocardial radioimmunoimaging. Method The first 60 rats were divided into three groups. In the experimental group,20 rats with acute myocardial lesion were injected with 0.2mci ~(99m)Tc-AcTnIMA, and killed at 2,4,6 and 8h after injection respectively (5 rats each time). Blood, liver, spleen, kidneys, healthy muscles, lungs and heart were taken,and injection dose%/g(ID%/g) and the ID%/g ratio of heartto lung(HLR)were calculated. In the pharmiccontrol group,20 rats with acute myocardial lesion were injected with 0.2mci ~ 99m Tc-N-IgG and were killed in the same way as theexperimental group.The lungs and hearts were taken,and ID%/g andHLR calculated. In the blank control, 20 healthy rats were injected with 0.2mci ~ 99m Tc-AcTnIMA and the subsequent procedures were just the same as the pharmic group. The second 50 rats with myocardial lesion were injected with 0.2mci ~ 99m Tc-AcTnIMA at 2,4,6,8,12,and 24h,and on the 3rd,5th,10th and 15th day after myocardial injury, respectively (5 rats each time), and killed at 4h after injection, and then ID%/g andHLR were calculated.Result It showed specific uptake of ~ 99m Tc-AcTnIMA by compromised cardiac muscles with the peak time of 4h, and the uptake had nothing to do with the time after lesion. Conclusion ~ 99m Tc-AcTnIMA can hopefully be a tracer of myocardial radioimmunoimaging to diagnose myocardial injury.