Purpose To explore the cardioprotective effect of cang-ai volatile oil(CAVO)on rats with cardiac function impairment model under low-pressure and low-oxygen environment in Tibet Plateau based on 7.0T cardiovascular magnetic resonance(CMR)imaging.Materials and Methods Forty SD rats were randomly divided into the normal group,the high altitude model group,the CAVO-treated group and the rhodiola rosea-treated group,with 10 rats in each group.Except for the normal group,the rats in other groups were transferred from the plain(500 m above sea level)to the Tibet Plateau(4 250 m above sea level)for two months,and then administered with the corresponding drugs by gavage for 14 d.The left ventricle function was measured by using a 7.0T high-field strength CMR and myocardial strain was analysed by using tissue tracing technique.HE staining was used to observe the morphology of cardiomyocytes,Masson staining to observe interstitial fibrosis,wheat germ agglutinin staining to observe cardiomyocyte hypertrophy,and transmission electron microscopy to observe the morphological changes of mitochondria in each group.Serum levels of creatine kinase,creatine kinase isoenzyme,lactate dehydrogenase,cardiac troponin T,superoxide dismutase,malondialdehyde and glutathione peroxidase were detected.Intracellular reactive oxygen species levels were detected using flow cytometry.Results The left ventricular ejection fraction of rats in the CAVO-treated group was higher than that of the high altitude model group[(66.61±1.38)％vs.(60.94±3.21)％;t=3.969,P=0.032];meanwhile,the global circumferential strain of the left ventricle in the CAVO-treated group was higher than that of the high altitude model group(-25.68±1.30 vs.-22.84±1.17;t=3.967,P=0.003).HE,Masson and wheat germ agglutinin staining showed hypertrophy and necrosis as well as interstitial fibrosis and ultrastructural disruption of cardiomyocytes in the high altitude model group,which improved after CAVO treatment.The level of cardiac troponin T in the serum of rats with CAVO treatment group was significantly decreased compared with that of the high altitude model group[(314.03±20.05)pg/ml vs.(518.30±18.13)pg/ml;1=13.090,P=0.001].Conclusion CAVO treatment can reduce cardiac injury caused by low-pressure hypoxia in high altitude,and its effect can be detected dynamically and non-invasively by 7.0T high-field strength CMR.

Objective: The occurrence of intramyocardial hemorrhage (IMH) and microvascular obstruction (MVO) in myocardial infarction (MI), known as severe ischemia/reperfusion injury (IRI), has been associated with adverse remodeling. APT102, a soluble human recombinant ecto-nucleoside triphosphate diphosphohydrolase-1, can hydrolyze extracellular nucleotides to attenuate their prothrombotic and proinflammatory effects. The purpose of this study was to temporally evaluate the therapeutic effect of APT102 on IRI in rats and to elucidate the evolution of IRI in the acute stage using cardiovascular magnetic resonance imaging (CMRI). Materials and Methods: Fifty-four rats with MI, induced by ligation of the origin of the left anterior descending coronary artery for 60 minutes, were randomly divided into the APT102 (n = 27) or control (n = 27) group. Intravenous infusion of APT102 (0.3 mg/kg) or placebo was administered 15 minutes before reperfusion, and then 24 hours, 48 hours, 72 hours, and on day 4 after reperfusion. CMRI was performed at 24 hours, 48 hours, 72 hours, and on day 5 post-reperfusion using a 7T system and the hearts were collected for histopathological examination. Cardiac function was quantified using cine imaging and IMH/edema using T2 mapping, and infarct/MVO using late gadolinium enhancement. Results: The extent of infarction (p < 0.001), edema (p < 0.001), IMH (p = 0.013), and MVO (p = 0.049) was less severe in the APT102 group than in the control group. IMH size at 48 hours was significantly greater than that at 24 hours, 72 hours, and 5 days after reperfusion (all p < 0.001). The left ventricular ejection fraction (LVEF) was significantly greater in the APT102 group than in the control group (p = 0.006). There was a negative correlation between LVEF and IMH (r = -0.294, p = 0.010) and a positive correlation between IMH and MVO (r = 0.392, p < 0.001). Conclusion APT102 can significantly alleviate damage to the ischemic myocardium and microvasculature. IMH size peaked at 48 hours post reperfusion and IMH is a downstream consequence of MVO. IMH may be a potential therapeutic target to prevent adverse remodeling in MI.

Objective To explore the best multiplicities of infection (MOI),the expression of the target gene and in vitro MR imaging of adenovirus vector-mediated transferrin receptor (TFRC) reporter gene transfection of human colorectal cancer Lovo cells.Methods Lovo cells were transfected with recombinant adenovirus (Ad-TFRC) at 5,10,50,100 MOI to determine the best MOI,and quantitative real-time PCR was performed to detect the eDNA of TFRC.The transfected cells were incubated in the culture medium including Tf-USPIO of various concentrations,and were observed by Prussian blue staining,then the cell viability was evaluated via Trypan blue staining.The labeled cells were scanned with 7.0T MR T2W,T2 map,T2* map sequences,and the signal intensities were analyzed.Results Ad-TFRC were successfully transfected into Lovo cells.The best MOI was 50,and the efficiency of infection was more than 90％.The relative expression amount of TFRC in transfected cells was higher than that in control Lovo cells by real-time quantitive PCR (P＜ 0.01).Prussian blue staining showed numerous blue iron particles in transfected cells when the best labeling concentration was 1.5 μg/ml.Trypan blue staining results of transfected Lovo cells and control Lovo cells was (93.80± 1.60)％ and (95.10±2.30) ％,respectively (P＞0.05).MR imaging in vitro showed that compared with control Lovo cells,the signal intensity decreased on T2WI,T2 map and T2* map sequences in transfected Lovo cells (P＜0.05).Conclusion TFRC reporter gene can be efficiently mediated by adenovirus for expression in Lovo cells.After magnetization labeling,7.0T MR imaging of Lovo cells can be successfully achieved in vitro.

OBJECTIVE: A failed electrocardiography (ECG)-trigger often leads to a long acquisition time (TA) and deterioration in image quality. The purpose of this study was to evaluate and optimize the technique of self-gated (SG) cardiovascular magnetic resonance (CMR) for cardiac late gadolinium enhancement (LGE) imaging of rats with myocardial infarction/reperfusion. MATERIALS AND METHODS: Cardiovascular magnetic resonance images of 10 rats were obtained using SG-LGE or ECG with respiration double-gating (ECG-RESP-gating) method at 7T to compare differences in image interference and TA between the two methods. A variety of flip angles (FA: 10°–80°) and the number of repetitions (NR: 40, 80, 150, and 300) were investigated to determine optimal scan parameters of SG-LGE technique based on image quality score and contrast-to-noise ratio (CNR). RESULTS: Self-gated late gadolinium enhancement allowed successful scan in 10 (100%) rats. However, only 4 (40%) rats were successfully scanned with the ECG-RESP-gating method. TAs with SG-LGE varied depending on NR used (TA: 41, 82, 154, and 307 seconds, corresponding to NR of 40, 80, 150, and 300, respectively). For the ECG-RESP-gating method, the average TA was 220 seconds. For SG-LGE images, CNR (42.5 ± 5.5, 43.5 ± 7.5, 54 ± 9, 59.5 ± 8.5, 56 ± 13, 54 ± 8, and 41 ± 9) and image quality score (1.85 ± 0.75, 2.20 ± 0.83, 2.85 ± 0.37, 3.85 ± 0.52, 2.8 ± 0.51, 2.45 ± 0.76, and 1.95 ± 0.60) were achieved with different FAs (10°, 15°, 20°, 25°, 30°, 35°, and 40°, respectively). Optimal FAs of 20°–30° and NR of 80 were recommended. CONCLUSION: Self-gated technique can improve image quality of LGE without irregular ECG or respiration gating. Therefore, SG-LGE can be used an alternative method of ECG-RESP-gating.
Animals ; Electrocardiography ; Gadolinium* ; Magnetic Resonance Imaging ; Methods ; Myocardial Infarction* ; Rats* ; Respiration

OBJECTIVE: Whether blood-brain barrier (BBB) disruption induced by chronic spontaneous hypertension is associated with beta-amyloid (Aβ) accumulation in the brain remains poorly understood. The purpose of this study was to investigate the relationship between BBB disruption and Aβ influx and accumulation in the brain of aged rats with chronic spontaneous hypertension. MATERIALS AND METHODS: Five aged spontaneously hypertensive rats (SHRs) and five age-matched normotensive Wistar-Kyoto (WKY) rats were studied. The volume transfer constant (Ktrans) obtained from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was used to evaluate BBB permeability in the hippocampus and cortex in vivo. The BBB tight junctions, immunoglobulin G (IgG), Aβ, and amyloid precursor protein (APP) in the hippocampus and cortex were examined with immunohistochemistry. RESULTS: As compared with WKY rats, the Ktrans values in the hippocampus and cortex of the SHRs increased remarkably (0.316 ± 0.027 min−1 vs. 0.084 ± 0.017 min−1, p < 0.001 for hippocampus; 0.302 ± 0.072 min−1 vs. 0.052 ± 0.047 min−1, p < 0.001 for cortex). Dramatic occludin and zonula occludens-1 losses were detected in the hippocampus and cortex of SHRs, and obvious IgG exudation was found there. Dramatic Aβ accumulation was found and limited to the area surrounding the BBB, without extension to other parenchyma regions in the hippocampus and cortex of aged SHRs. Alternatively, differences in APP expression in the hippocampus and cortex were not significant. CONCLUSION: Blood-brain barrier disruption is associated with Aβ influx and accumulation in the brain of aged rats with chronic spontaneous hypertension. DCE-MRI can be used as an effective method to investigated BBB damage.
Alzheimer Disease ; Amyloid ; Animals ; Blood-Brain Barrier* ; Brain* ; Hippocampus ; Hypertension* ; Immunoglobulin G ; Immunohistochemistry ; Magnetic Resonance Imaging* ; Methods ; Occludin ; Permeability ; Rats* ; Rats, Inbred SHR ; Rats, Inbred WKY ; Tight Junctions

Objective To investigate the character of aquaporin-1(AQP-1)expression in adrenal gland in diabetes mellitus and evaluate adrenal gland damage and function alterations by DWI with multiple b values. Methods Twenty male Sprague-Dawley rats were randomly selected by computer and randomized into 2 groups:untreated controls(n=10)and diabetes(DM)(n=10). Rats in diabetes group were fed with high-sucrose and high-fat diet, controls were fed with common diet. After fed with high-sucrose and high-fat diet for 4 weeks, rats in diabetes group were injected with streptozotocin(STZ). Forty days after diabetes induction with streptozotocin(STZ), MR imaging was performed in a 7.0 T scanner. Venous blood from the tails was collected before MRI scan to measure blood glucose, blood glucose more than 16.7 mmol/L wasregarded as diabetic status. All the rats underwent DWI with 18 b values(0 to 4500 s/mm2). Maps of pure diffusion coefficients(D), pseudo-diffusion coefficients(D*)and ultra-high ADC(ADCuh)were acquired. Rats were sacrificed after MRI scan for adrenal gland histopathology, AQP-1 immunohistochemistry analysis and AQP-1 optical density(OD)measurements. Student t test was used to compare the difference of D*, D, ADCuh and OD of AQP-1 between two groups. Results Eight diabetic animals developed hyperglycemia(two rats died during the modeling process). MRI scan was performed in all of the 18 rats. Signal intensity of D*map, D map and ADCuh map decreased gradually. ADCuh increased significantly in DM animals(0.24 ± 0.06) × 10-3mm2/s compared with control animals(0.18 ± 0.07) × 10-3 mm2/s(P<0.05), whereas there was no significant difference found between the two groups in their respective D*and D values(P>0.05). There was a noticeable increase in the AQP-1 labeling in the adrenal cell membrane and cytoplasm in DM animals compared with control animals. DM rats showed an increased OD value of AQP-1 in adrenal gland compared with the control animals(P<0.05). Conclusions We found significantly higher AQP-1 expression in adrenal gland in DM animals compared with controls. Ultra-high b-Values DWI may work as a useful way for noninvasive evaluation the change of adrenal function in DM.

OBJECTIVE: To understand microstructural changes after myocardial infarction (MI), we evaluated myocardial fibers of rhesus monkeys during acute or chronic MI, and identified the differences of myocardial fibers between acute and chronic MI. MATERIALS AND METHODS: Six fixed hearts of rhesus monkeys with left anterior descending coronary artery ligation for 1 hour or 84 days were scanned by diffusion tensor magnetic resonance imaging (MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). RESULTS: Comparing with acute MI monkeys (FA: 0.59 ± 0.02; ADC: 5.0 ± 0.6 × 10(-4) mm2/s; HA: 94.5 ± 4.4°), chronic MI monkeys showed remarkably decreased FA value (0.26 ± 0.03), increased ADC value (7.8 ± 0.8 × 10(-4) mm2/s), decreased HA transmural range (49.5 ± 4.6°) and serious defects on endocardium in infarcted regions. The HA in infarcted regions shifted to more components of negative left-handed helix in chronic MI monkeys (-38.3 ± 5.0°-11.2 ± 4.3°) than in acute MI monkeys (-41.4 ± 5.1°-53.1 ± 3.7°), but the HA in remote regions shifted to more components of positive right-handed helix in chronic MI monkeys (-43.8 ± 2.7°-66.5 ± 4.9°) than in acute MI monkeys (-59.5 ± 3.4°-64.9 ± 4.3°). CONCLUSION: Diffusion tensor MRI method helps to quantify differences of mechanical microstructure and water diffusion of myocardial fibers between acute and chronic MI monkey's models.
Anisotropy ; Coronary Vessels ; Diffusion* ; Endocardium ; Haplorhini ; Heart ; Ligation ; Macaca mulatta* ; Magnetic Resonance Imaging* ; Methods ; Myocardial Infarction* ; Water

Objective Using 7.0 T diffusion tensor imaging(DTI) to study myocardial fibers character in isolated rats heart in aspect of water molecular diffusion, myocardial mechanics and microstructure. Methods Fixed male rats heart (n=10) underwent DTI and the myocardial structures were quantitatively measured by Diffusion Toolkit and Matlab. The characteristic of myocardial fibers arrangement was observed and FA values and ADC values of myocardial fibers, myocardial fibers density and length, mean helix angle of left ventricular were calculated as well. Mean helix angle of anterior wall, ventricular septum, lateral wall and posterior wall of epicardium and endocardium were compared by using one?way ANOVA. Results The SD rats' myocardial fibers appeared in compact and inerratic distribution from epicardium to endocardium. Compared with HE staining, regular direction and arrangement in fibers were showed in myocardial fibers tracer map and tensor map in papillary muscle plane. Quantitative analysis showed that ADC value of SD rats' myocardial fibers was (9.6 ± 3.6) × 10-4 mm2/s, FA value was 0.80 ± 0.04, myocardial fibers density was (981±24) tracks/mm3 and myocardial fibers length was (6.18±1.71)mm. Mean helix angle of left ventricular epicardium to endocardium ranged from-81.37° to 0° and then gradually change to 82.83° . There were no significant differences in mean helix angle of anterior wall, ventricular septum, lateral wall and posterior wall of epicardium and endocardium, respectively (F=2.25, 0.40, P>0.05). Conclusions This study shows that DTI is an effective method to quantitatively measure the characteristics of myocardial fibers. This study provides useful information for further study of myocardial fibers in heart disease models.

Urokinase plasminogen activator receptor (uPAR) is a membrane protein which is attached to the cellular external membrane. The uPAR expression can be observed both in tumor cells and in tumor-associated stromal cells. Thus, in the present study, the human amino-terminal fragment (hATF), as a targeting element to uPAR, is used to conjugate to the surface of superparamagnetic iron nanoparticle (SPIO). Flowcytometry was used to examine the uPAR expression in different tumor cell lines. The specificity of hATF-SPIO was verified by Prussian blue stain and cell phantom test. The imaging properties of hATF-SPIO were confirmed in vivo magnetic resonance imaging (MRI) of uPAR-elevated colon tumor. Finally, the distribution of hATF-SPIO in tumor tissue was confirmed by pathological staining. Results showed that the three cells in which we screened, presented different expression characteristics, i. e., Hela cells strongly expressed uPAR, HT29 cells moderately expressed uPAR, but Lovo cells didn't express uPAR. In vitro, after incubating with Hela cells, hATF-SPIO could specifically combined to and be subsequently internalized by uPAR positive cells, which could be observed via Prussian blue staining. Meanwhile T2WI signal intensity of Hela cells, after incubation with targeted probe, significantly decreased, and otherwise no obvious changes in Lovo cells both by Prussian blue staining and MRI scans. In vivo, hATF-SPIO could be systematically delivered to HT29 xenograft and accumulated in the tumor tissue which was confirmed by Prussian Blue stain compared to Lovo xenografts. Twenty-four hours after injection of targeting probe, the signal intensity of HT29 xenografts was lower than Lovo ones which was statistically significant. This targeting nanoparticles enabled not only in vitro specifically combining to uPAR positive cells but also in vivo imaging of uPAR moderately elevated colon cancer lesions.
Cell Line, Tumor ; Colonic Neoplasms ; diagnosis ; Ferric Compounds ; Humans ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; chemistry ; Molecular Imaging ; methods ; Receptors, Urokinase Plasminogen Activator ; chemistry ; Staining and Labeling

Objective To construct adenovirus vector containing firefly luciferase reporter gene (AdLuc) and infect bone marrow mesenchymal stem cells (BMSC),then to take bioluminescence imaging in vitro and in vivo for identification.Methods The luciferase gene was amplified with PCR from psiCHECK-2 plasmid and cloned into the adenoviral shuttle vector (pShuttle-CMV).It was confirmed by Nhe Ⅰ/Xba Ⅰ digestion and sequencing.PShuttle-CMV-Luc and backbone vector (pAdeno) were homologous recombined.Then the recombinant plasmid was packaged in HEK293 cells and the virus titer was detected.The BMSC were infected by the recombinant adenovirus.The bioluminescence imaging in vitro was performed to determine the best multiplicity of infection (MOI),and the relationship between bioluminescence intensity and MOI was analyzed by curve fitting regression analysis.Viability was evaluated via Trypan blue staining.The transfected BMSC (l× 106) were implanted into the muscles of forelimb of SD rats,and then tracked by bioluminescence imaging in vivo.Cell viability was compared using two-way repeated measures analysis of variance between groups.Results Enzyme digestion and sequence analysis indicated that Ad-Luc was successfully constructed.The virus titer was 1 × 1010 plaque forming unit (PFU)/ml.The bioluminescence detection in vitro showed that Ad-Luc could infect BMSC high efficiently to express luciferase and the best MOI was 50.The bioluminescence intensity enhanced with increase of MOI (R2 =0.98).No statistically significant difference was found in cell viability between transfected and untransfected BMSC at 1,3,5,7 d.The cell survival rates were (92.5±2.3)％ vs (94.1±1.8)％,(91.4±0.9)％ vs (92.7±2.0)％,(92.1±1.6)％ vs (93.3± 2.4) ％,(91.9 ± 1.5) ％ vs (93.0 ± 3.1) ％,respectively (F =4.38,P ＞ 0.05).The bioluminescence imaging in vivo showed that BMSC survived 1,3,7 d after implantation.However,bioluminescence signal decreased gradually over time.Conclusion It is feasible to apply the optical reporter gene imaging for tracing transplanted stem cells in vitro and in vivo due to the effective transformation of luciferase reporter gene into BMSC by adenovirus vector.