Objective To evaluate the anatomic localization and size of acute necrotic myocardium in the ischemic-reperfused rat hearts using 99m TC-Glucarate and microSPECT/CT.Methods The ischemic-reperfused ( IR) rat heart models were established by ligating left anterior descending coronary artery for 60 min.99mTC-Glucarate was intravenously injected into the rats 24 hours after IR operations .Images were acquired 30 min after administration of 99m TC-Glucarate using microSPECT/CT. Anatomic localization and size of acute necrotic myocardium were analyzed with microSPECT/CT imaging , and these results were compared to those determined by triphenyltetrazolium chloride ( TTC ) staining.Results The microSPECT/CT images showed hot spot accumulations of 99mTC-Glucarate in IR hearts (the heart-to-liver ratio was 1.90 ±0.33), not in controls (P <0.05).The anatomic localization of 99mTC-Glucarate-labeled necrotic myocardium were in correspondence with TTC staining results .The hot spot size was related significantly to necrotic myocardial size determined by TTC staining ( R2 =0.964 ) .Conclusions The localization and size of acute necrotic myocardium can be assessed by non-invasive microSPECT/CT imaging with99m Tc-Glucarate.

Objective To investigate the role of RhoA /Rho-kinase pathway in rat models of left heart disease-as-sociated pulmonary hypertension ( PH-LHD) .Methods Twenty male SD rats (3-4 week-old, 90-100 g) were randomly divided into two groups (10 rats in each group):the group C ( control group) with sham operation, and group H ( pulmo-nary arterial hypertension) .The rat model of left heart disease-associated pulmonary hypertension was established by supra-coronary aortic banding in the group H, and the sham surgery was applied for the rats in the group C ( The titanium clip was fixed at the mediastinal tissue adjacent to the artery rather than the ascending aorta).On day 60 after the operation, the cardiac functions, including right ventricular systolic pressure and pulmonary artery pressure were evaluated.After that, all rats were sacrificed and treated with cardiopulmonary lavage in vivo until the lung became white.Then the left lung tissues were fixed in 4%paraformaldehyde for pathological observation while the right lung tissues were frozen for mRNA detec-tion.Results Compared with the group C, both ventricular systolic pressure and pulmonary artery pressure in the group H were increased significantly (P<0.01).Pathological data demonstrated that the pulmonary artery walls in H group were much thicker than that in the group C.Moreover, vascular wall hypertrophy index in the group H was increased greatly compared with that in the group C (P<0.01).QPCR data showed that mRNA levels of Rho kinase, RhoA and ET-A R in the group H were up-regulated compared with the group C ( P<0.01) .Conclusions Rat model of left heart disease-asso-ciated pulmonary arterial hypertension can be successfully established by supracoronary aortic banding.Rho-kinase-media-ted pathway may contribute to the pathogenesis and progress of left heart disease-associated pulmonary arterial hypertension.