99Tcm-MIBI评价缺血预适应心肌的实验研究

目的　研究

Experimental study of evaluating ischemic preconditioning myocardium with 99 Tcm-sestamibi

Objective　To investigate the kinetics of uptake,washout and retention of 99　Tcm-sestamibi in ischemic preconditioning (IP) myocardium and the feasibility of using 99　Tcm-sestamibi to evaluate IP myocardium.Methods　The isolated and perfused rat hearts were divided randomly into three groups:normal,ischemic (IS) and ischemic precoditioning (IP).The myocardial 99　Tcm-sestamibi activity was monitored during accumulation and clearance phases,meanwhile cumulative lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) contents were measuered over 75 minutes of the effluent from each heart.After perfusion each heart was carved up for measuring myocardial infarct size using tripheyl tetrazolium chloride (TTC) technique,and for determining myocardial 99　Tcm-sestamibi retention. Results　Uptakes of 99　Tcm-sestamibi in normal,IS and IP myocardium were (388±40)/min),(186±33)/min and (325±44)/min,respectively;washout rates at 30 minutes were (5.13±0.88)%,(8.88±0.95)%and (6.67±0.87)%,respectively;and retention rates of 99　Tcm-sestamibi per gram myocardium of normal,IS and IP groups were (344±17),(158±23) and (277±50)×103/min,respectively.There were statistic differences in uptake rates,washout rates and retention rates of 99　Tcm-sestamibi between IS and IP groups,P<0.001.Average infarct size in IP rats was less than in IS rats ［(10.7±3.7)% and (23.8±8.6)%,respectively,P<0.001)］.Total LDH release from IP rats was less than from IS rats ［(64.6±26.0) U/L and (101.8±32.0)U/L,respectively,P<0.001］.Total ALP release from IP rats was also less than from IS rats ［(14.4±6.0)U/L and (24.5±10.0)U/L,respectively,P<0.05］. Conclusions　IP in isolated rat heart can induce infarct size restraint and cell kinase leakage reduction.99Tcm-sestamibi is a sensitive technique for evaluating ischemic preconditioning myocardium.