The Molecular Imaging Evaluation Of Trauma-induced Secondary Cardiac Injury

Objective:This study is based on the early detection of cardiac dysfunction in vitro and normal cardiac function in vivo after the original discovery of non-fatal mechanical trauma,and the damage of myocardial mitochondria and the decrease of myocardial autophagy,which are intended to be viewed from the molecular imaging point of view.To observe the changes of mitochondrial function and glucose energy metabolism after myocardial injury.In order to provide ethical basis for clinical search for effective detection of early myocardial injury after mechanical trauma,and to provide ethical basis for early warning and intervention of the occurrence of delayed cardiac injury.Methods:Wistar rats weighing about 180²20 g were divided into normal group,trauma model group and auto-macrophage agonist trauma group.The changes of cardiac function at 1h,3h,6h,12h and 24 h after trauma were observed,respectively.The autophagy marker proteins LC3-?,Beclin-1 and mitochondrial membrane potential of myocardial tissue and myocytes were measured at 24h after trauma.On the ^99mTc-MIBI myocardial imaging images,?ROI regions of interest?technique was used to sketch the heart?heart,H?and superior mediastinal region?uppermediastinum,M?,and the average count was obtained.The uptake and elution of cardiac ^99mTc-MIBI were semi-quantitatively analyzed by 30min and H/M ratio at 3.5 h.The ^99mTc-MIBI uptake ratios of isolated rat ventricular walls were collected.¹⁸F-FDG and ¹³N-NH₃·H₂O Micro-PET molecular imaging were performed before and 6 hours and 7 days after trauma respectively to observe myocardial metabolism and perfusion.Results:1.Compared with the normal control group,the expression of LC3-?and beclin1 protein decreased at 1h after trauma and reached the lowest level at 6h after trauma,then gradually recovered,and returned to normal level at 24h after trauma?p>0.05?.2.Compared with the normal control group,the mitochondrial membrane potential decreased and the heart/mediastinum ratio decreased by ^99mTc-MIBI myocardial imaging in rats 6 hours after trauma?p<0.05?.No abnormal changes were observed in ¹⁸F-FDG myocardial glucose metabolism imaging and ¹³N-NH₃ perfusion imaging.However,7days after trauma,myocardial ¹⁸F-FDG imaging showed that the glucose metabolism in anterior wall of myocardium was higher than that in other ventricular walls,and the ratio of heart to mediastinum was decreased by myocardial ^99mTc-MIBI imaging.The local radioactivity value?count/g?of the anterior wall was lower than that of the normal control group.3.Compared with the normal control group,the myocardial autophagy level and^99mTc-MIBI myocardial imaging were significantly improved at 6h after trauma with autophagy agonist?PARA?,before trauma?p<0.05?,and the in vitro cardiac function was restored to normal?p<0.05?.Conclusion:1.The decrease of mitochondrial membrane potential in myocardial tissue after mechanical trauma may lead to delayed cardiac injury after trauma by inducing autophagy.2.Early mitochondrial dysfunction after mechanical trauma and myocardial ischemic heart injury 7 days later.⁹9m9m Tc-MIBI myocardial imaging can be used as one of the early warning indicators of posttraumatic delayed cardiac injury.