[Ameliorative Effects of Cang-ai Volatile Oil on Left Ventricular Remodeling in Rats].

Objective: To evaluate with 7T cardiac magnetic resonance tissue tracking imaging (CMR-TT) the ameliorative effect of Cang-ai volatile oil (CAVO) on left ventricular remodeling (LVR) in rats induced by isoproterenol (ISO), and to make preliminary investigation into CAVO's effects on endothelial dysfunction in LVR. Methods: A total of 35 healthy male Sprague-Dawley (SD) rats were randomly assigned to two groups, the experimental group ( n=27) and the normal control group ( n=8). The rat model of LVR was established by subcutaneous injection of ISO solution at 10 mg·kg -1·d -1 at multiple sites for 10 consecutive days. After modeling was completed, the surviving rats ( n=24) in the experimental group were then randomly assigned to the blank experimental group, CAVO group, and Shexiang Baoxin pill (SXBXP) group ( n=8 in each group). Rats in each group were given via gavage the corresponding intervention medicine or an equivalent amount of normal saline solution for 28 consecutive days. At the end of modeling and intragastric intervention, 7T CMR cine sequence scanning was conducted to collect data. Then, post-processing software CVI42 was used to analyze the images and to compare and contrast the changes in the parameters of left ventricular cardiac function and myocardial strain in each group before and after the administration of the medication. The rats were sacrificed after MRI scanning, and their hearts were harvested for pathological examination. The levels of serum biochemical indicators were measured by enzyme-linked immunosorbent assay (ELISA). Results: CAVO significantly increased LV ejection fraction and overall myocardial strain parameters in LVR rats, while it decreased LV volume, mass, and serum levels of endothelial function indicators in LVR rats. In addition, pathological staining showed marked improvements in the hypertrophy, necrosis and interstitial fibrosis of cardiomyocytes. Conclusion: Through the regulation of myocardial vascular endothelial function, CAVO can significantly improve cardiac functions in LVR rats, delay the process of ventricular remodeling, and have a certain amount of protective effect on cardiac structure and function in rats.

[Basic Research on Neuroprotective Effect of Volatile Oil of Cang Ai after Cerebral Ischemia-Reperfusion Injury Based on Diffusion Tensor Imaging].

OBJECTIVE: To study the neuroprotective effect of inhalation of volatile oil of Cang Ai (VOCA) on cerebral ischemia-reperfusion injury model by MRI diffusion tensor imaging. METHODS: Twenty-four healthy adult male SD rats were randomly divided into sham operation group, model (middle cerebral artery occlusion (MCAO) ) group and VOCA group. Evaluated the degree of neurological impairment of rats in each group immediately after successful establishment of model or 7 d later according to Zea Longa scoring. Coronal diffusion tensor imaging (DTI) scan was performed at 3 h, 3 d, and 7 d after the model successfully established by using 7.0 T magnetic resonance imaging. Measured the apparent diffusion coefficient (ADC) and anisotropy score (FA) of the DTI in the striatal region and the motion flat zone of the maximum infarct level and then calculate the relative apparent diffusion coefficient (rADC) and relative anisotropy score (rFA). TTC staining was used to evaluate the cerebral infarction volume of rats in each group at 7 d post model establishment, and the correlation analysis of rFA, rADC and neural score was performed. RESULTS: No neurological defect was detected in mice in the sham operation group. The MCAO group and the VOCA group showed neurological defect to different degrees. The neurological function score of the VOCA group was obviously lower than that of MCAO group at 7 th day (P<0.05). The DTI scan results showed that the rADC value of striatum of rats in VOCA group was higher than that in MCAO group at 3 h and 3 d after modeling (P<0.05), while there was no significant difference between the three groups at 7 th day. The rADC value of the motor cortex in the VOCA group was higher than that in the MCAO group at 3 h after modeling (P<0.01), and there was no significant difference at 3 rdday and 7 thday. The rFA value of striatum in VOCA group was higher than that in MCAO group at 3 rd day and 7 th day after modeling (P<0.05). There were no significant differences in rFA value between the MCAO and the VOCA group at three time points. TTC staining results showed that there was no infarcted area in the sham operation group, and the infarct volume in the VOCA group was smaller than that of the MCAO group (P<0.05). Correlation analysis showed that the striatum rFA value was highly correlated with neurological scores (r=－0.847, P<0.01). CONCLUSION: For the first time, we found that VOCA can effectively protect the neurological function of MCAO rats by reducing the toxic edema of cells in the ischemic area and accelerating the recovery of nerve fiber bundles after cerebral ischemia and reperfusion. rFA and rADC values can be used as effective indicators to evaluate the recovery of nerve function after cerebral ischemia and reperfusion.

[Magnetic Resonance Imaging Tissue Feature Tracking for Cardiac Amyloidosis].

OBJECTIVE: To detect cardiac amyloidosis (CA) using cardiac magnetic resonance feature tracking(CMR-FT). METHODS: Forty-three CA patients and 24 healthy volunteers underwent steady-state free precession cine sequence on 3.0T MRI after injection of Magnevist. Software cvi 42 was used for analyzing the left ventricular function including left ventricular mass (diastole) (LVMD), left ventricular mass (systole) (LVMS), left ventricle end-diastolic volume (LVEDV), left ventricle end-systolic volume (LVESV), left ventricle stroke volume (LVSV), and left ventricular ejection fraction (LVEF), as well as myocardial strains including 3D global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS), and 2D endocardial and epicardial longitudinal strain, circumferential strain, and radial strain (ENDO-LS, EPI-LS, ENDO-CS, EPI-CS, ENDO-RS, and EPI-RS). The global and layer-specific strains were compared between the CA patients with LVEF >50%, the CA patients with LVEF ≤50%, and the healthy controls. RESULTS: For the left ventricular function, the CA patients had greater myocardial mass than the healthy controls (P < 0.05); the CA patients with LVEF ≤50% had greater LVESV and lower LVSV than those with LVEF >50% (P < 0.05). For the global strains, significant differences also appeared in GLS and GCS among the three groups (all P < 0.05). The CA patients had lower GRS than the healthy controls (P < 0.05), while no significant difference was found in GRS between the CA patients with LVEF >50% and those with LVEF ≤50% (P>0.05). For the layer-specific strains, significant differences in ENDO-LS, EPI-LS, ENDO-CS, EPI-CS, ENDO-RS, and EPI-RS were found among the three groups (all P < 0.05). There were significant correlations between GLS and LVEF (r=-0.404, P=0.016), and between GCS and LVEF (r=-0.602, P < 0.001) in the CA patients. CONCLUSION: CMR-FT can assess not only global strains but also layer-specific strains for the myocardial function of CA patients.

Noninvasive Imaging of Ras Activity by Monomolecular Biosensor Based on Split-Luciferase Complementary Assay.

Deregulated activity of Ras GTPases has been observed in many types of human cancers, and contributes to the diverse aspects of carcinogenesis. Although the significance in tumorigenesis has been widely accepted and many therapeutic drugs are under development, little attention has been dedicated to the development of sensors for the Ras activity in vivo. Therefore, based on the split firefly luciferase complementation strategy, we developed a monomolecular bioluminescent biosensor to image endogenous Ras activity in living subject. In this biosensor, two inactive luciferase fragments are sandwiched by Raf-1, whose conformation changes upon GTP-Ras binding. Thus, the Ras activity can be surrogated by the intensity of the complementary luciferase. The bioluminescence analyses demonstrated that this novel biosensor behaved the robust and sensitive reporting efficiency in response to the dynamical changes of Ras activity, both in living colorectal cancer cells and in vivo. Compared to the traditional method, such as the pull-down assay, the bioluminescent sensor is simply, noninvasive, faster and more sensitive for the analysis of the endogenous Ras activity. This innovative work opens up the way for monitoring the preclinical curative effect and high-throughput screening of therapeutic drugs targeting Ras pathways.

Dynamic Diffusion Tensor Imaging Reveals Structural Changes in the Bilateral Pyramidal Tracts after Brain Stem Hemorrhage in Rats.

BACKGROUND AND PURPOSE: Few studies have concentrated on pyramidal tract (PY) changes after brain stem hemorrhage (BSH). In this study, we used a diffusion tensor imaging (DTI) technique and histologic identification to investigate longitudinal PY changes on both the contralateral and ipsilateral sides after experimental BSH. METHODS: BSH was induced in 61 Sprague-Dawley rats by infusing 30 µl of autogenous tail blood into each rat's right pons. DTI and motor function examinations were performed repeatedly on days 1, 3, 7, 14, and 28 after surgery. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity were measured in the bilateral PYs. The axon and myelin injury in the PY were evaluated by histologic study. RESULTS: As compared with normal controls, the bilateral PYs in rats with induced BSH showed an early decrease and a late increase in FA and an early increase and a late decrease in MD. A progressive decrease in axial diffusivity with dramatic axon loss from day 1 to day 28 after BSH was found bilaterally. The bilateral PYs showed an early increase and a late decrease in radial diffusivity. Early myelin injury and late repair were also detected pathologically in the bilateral PYs of rats with BSH. Thus, the early motor function deficits of rats with BSH began to improve on day 14 and had almost completely disappeared by day 28. CONCLUSIONS: DTI revealed dynamic changes in the bilateral PYs after BSH, which was confirmed by histologic findings and which correlated with motor function alteration. These findings support the idea that quantitative DTI can track structural changes in the bilateral PYs and that DTI may serve as a noninvasive tool to predict the prognoses of patients with BSH.

Injection of Aß1-40 into hippocampus induced cognitive lesion associated with neuronal apoptosis and multiple gene expressions in the tree shrew.

Alzheimer's disease (AD) can incur significant health care costs to the patient, their families, and society; furthermore, effective treatments are limited, as the mechanisms of AD are not fully understood. This study utilized twelve adult male tree shrews (TS), which were randomly divided into PBS and amyloidbetapeptide1-40 (Aß1-40) groups. AD model was established via an intracerebroventricular (icv) injection of Aß1-40 after being incubated for 4 days at 37 °C. Behavioral, pathophysiological and molecular changes were evaluated by hippocampal-dependent tasks, magnetic resonance imaging (MRI), silver staining, hematoxylin-eosin (HE) staining, TUNEL assay and gene sequencing, respectively. At 4 weeks post-injection, as compared with the PBS group, in Aß1-40 injected animals: cognitive impairments happened, and the hippocampus had atrophied indicated by MRI findings; meanwhile, HE staining showed the cells of the CA3 and DG were significantly thinner and smaller. The average number of cells in the DG, but not the CA3, was also significantly reduced; furthermore, silver staining revealed neurotic plaques and neurofibrillary tangles (NFTs) in the hippocampi; TUNEL assay showed many cells exhibited apoptosis, which was associated with downregulated BCL-2/BCL-XL-associated death promoter (Bad), inhibitor of apoptosis protein (IAP), Cytochrome c (CytC) and upregulated tumor necrosis factor receptor 1 (TNF-R1); lastly, gene sequencing reported a total of 924 mobilized genes, among which 13 of the downregulated and 19 of the upregulated genes were common to the AD pathway. The present study not only established AD models in TS, but also reported on the underlying mechanism involved in neuronal apoptosis associated with multiple gene expression.

LOX-1-Targeted Iron Oxide Nanoparticles Detect Early Diabetic Nephropathy in db/db Mice.

PURPOSE: Activation of the low-density lipoprotein receptor 1 (LOX-1) contributes to pervasive inflammation in early diabetic nephropathy (DN). This study determined the feasibility of anti-LOX-1-ultrasmall superparamagnetic iron oxide nanoparticles (USPIOs) for noninvasive detection of inflammatory renal lesions in early DN. PROCEDURES: Anti-mouse LOX-1 antibody was conjugated to polyethyleneglycol-coated USPIOs. In vitro analysis of USPIOs uptake was performed in RAW264.7 macrophages. DN and control mice were imaged by MRI prior to and 24 h after contrast treatment. RESULTS: Anti-LOX-1 USPIOs were selectively taken up by macrophages, and kidney T2* MRI showed a lower signal intensity in the cortex of DN mice after 24 h administration of anti-LOX-1 USPIOs. Positive Perl's staining in DN lesions, indicating the presence of iron oxide, was consistent with immunohistochemistry indicating the presence of LOX-1 and CD68. CONCLUSIONS: This report shows that anti-LOX-1 USPIOs detect LOX-1-enriched inflammatory renal lesions in early DN mice. Our study provides important information for characterizing and monitoring early DN.

[Bone mesenchymal stem cell transplantation for acute myocardial infarction: in vivo tracing with multi-modality molecular imaging].

OBJECTIVE: To investigate the feasibility of tracking bone mesenchymal stem cell (BMSCs) dual- labeled with polyethylenimine 2k-superparamagnetic iron oxide (PEI2k-SPIO) and Luciferase transplantation for acute myocardial infarction in vivo by using magnetic resonance imaging (MRI) and fluorescence imaging. METHODS: BMSCs/Luciferase was incubated with culture medium containing PEI2k-SPIO for 24 h. Prussian-blue staining and MTT were used to assess the efficacy and safety of labeling with PEI2k-SPIO. Guided with echocardiography, the dual-labeled BMSCs were injected into the margin of infarction myocardium. MRI and fluorescence imaging were performed to monitor the cells in vivo at different times (1,2,3,7 d). RESULTS: As demonstrated by MTT, there was no significant difference in survival rate between the labeled and unlabeled cells (P>0. 05). Within a week after transplantation, all PEI2k-SPIO-labeled BMSCs showed a significant decreased signal on MRI. Dual-labeled BMSCs were detected bioluminescence with fluorescence imaging, but disappeared after one week. CONCLUSION: Multi- modality imaging can not only trace the location of labeled BMSCs but also demonstrate the survival of labeled BMSCs in vivo.

Multimodality imaging assessments of response to metformin therapy for breast cancer in nude mice.

BACKGROUND: Metformin is the most widely used anti-diabetic drug in the world. An increasing body of evidence shows metformin also blocks cell cycle progression and selectively induces apoptosis via caspase activation in some breast tumor cells. Diffusion-weighted imaging (DWI) and bioluminescence imaging (BLI) have great potential in the evaluation of the early response to cancer therapies. We used DWI and BLI in evaluating the response of breast cancer to metformin. METHODS: The luciferase-engineered human breast cancer cell line MDA-MB-231 was inoculated into the mammary fat pad of nude mice. Twelve female nude mice bearing tumors were divided into two groups. The mice in the treatment group received metformin (2 mg/ml in drinking water daily) after tumor inoculation, and the mice in the control group were offered drinking water without any drug added. We performed 7T magnetic resonance imaging and optical imaging every week. Imaging included T1- and T2-weighted imaging, DWI, and BLI. After imaging. The tumors were collected and subjected to histological analysis. RESULTS: The mean photons/second of tumors in the treatment group was (3.00 ± 0.43)× 10(6) at day one, (1.01 ± 0.14)× 10(7) at 2 weeks, (5.79 ± 1.42)× 10(7) at 4 weeks, and (2.33 ± 0.70)× 10(7) at 8 weeks. The mean photons/second of tumors in the control group was (3.29 ± 0.59)× 10(6) at day one, (3.59 ± 0.63)× 10(7) at 2 weeks, (3.87 ± 0.56)× 10(8) at 4 weeks, and (4.12 ± 1.72)× 10(8) at 8 weeks. Compared to the control group, the treatment group showed an obvious decrease in the mean bioluminescence (photons/s) of the tumors and fewer metastases. Histological examination confirmed the presence of fewer metastases. DWI showed the apparent diffusion coefficient (ADC) value of the tumors; the mean ADC value was (0.9287 ± 0.04346)× 10(-3) mm(2)/s in the treated tumors and (0.7553 ± 0.01804)× 10(-3) mm(2)/s in the untreated tumors. The ADC value of tumors in the treatment group was significantly higher than the control tumors (P = 0.0013). CONCLUSIONS: The growth and metastasis of MDA-MB-231 breast cancer may be inhibited by metformin. DWI and BLI have great potentials in the evaluation of the early response to metformin treatment. BLI has a high degree of sensitivity and is able to detect micrometastasis, thus can be used for identifying tumor metastasis in vivo.

Construction and identification of the adenoviral vector with dual reporter gene for multimodality molecular imaging.

In this study, the recombinant adenovirus (Ad) vector containing dual reporter gene [i.e. human transferrin receptor gene (TFRC) and firefly luciferase reporter gene] was constructed to provide a novel experimental tool for magnetic resonance (MR) and bioluminescence dual-modality molecular imaging. The cDNA of TFRC was amplified by polymerase chain reaction (PCR) and cloned into the multiple cloning site of pShuttle-CMV-CMV-Luciferase vector. After identification by Sfi I digestion and sequencing, pShuttle-TFRC-Luciferase vector and the adenoviral backbone vector (pAdeno) were subjected to homologous recombination. The correct recombinant plasmid was then transfected into 293 packaging cells to produce adenoviral particles and confirmed by PCR. After infection of human colorectal cancer LOVO cells with Ad-TFRC-Luciferase, the expressions of transferrin receptor (TfR) and luciferase protein were detected respectively by Western blotting and bioluminescence imaging in vitro. The results showed that TFRC gene was successfully inserted into the adenoviral shuttle vector carrying luciferase gene. DNA sequence analysis indicated that the TFRC gene sequence in the shuttle plasmid was exactly the same as that reported in GenBank. The recombinant plasmid was identified correct by restriction digestion. Ad-TFRC-Luciferase recombinant adenovirus was constructed successfully, and the virus titer was 1.6×10(10) pfu/mL. Forty-eight h after dual reporter gene transfection, the expressions of TfR and luciferase protein were increased significantly (P<0.01). It was concluded that the recombinant adenovirus vector with dual reporter gene was successfully established, which may be used for in vivo tracing target cells in multimodality imaging.

Alteration of sweet taste in high-fat diet induced obese rats after 4 weeks treatment with exenatide.

Exenatide, a glucagon-like peptide-1 (GLP-1) receptor agonist, is effective in inducing weight loss. The exact mechanisms are not fully understood. Reduced appetite and food intake may play important roles. Sweet taste contributes to food palatability, which promotes appetite. Interestingly, GLP-1 and its receptor are expressed in the taste buds of rodents and their interaction has an effect on mediating sweet taste sensitivity. Our aim was to investigate whether sweet taste will be changed after long term treatment with exenatide. The results showed that high-fat diet induced obese rats (HF-C) presented metabolic disorders in food intake, body weight, blood glucose and lipid metabolism compared with long term exenatide treated obese rats (EX) and normal chow fed control rats (NC). Meanwhile, greater preference for sweet taste was observed in HF-C rats but not in EX rats. Compared with NC rats, brain activities induced by sweet taste stimulation were stronger in HF-C rats, however these stronger activities were not found in EX rats. We further found reduced sweet taste receptor T1R3 in circumvallte taste buds of HF-C rats, while GLP-1 was increased. Besides, serum leptin was evaluated in HF-C rats with decreased leptin receptor expressed in taste buds. These changes were not observed in EX rats, which suggest them to be the underlying hormone and molecular mechanisms responsible for alterations in sweet taste of HF-C rats and EX rats. In summary, our results suggest that long term treatment with exenatide could benefit dietary obese rats partially by reversing sweet taste changes.

[MR imaging of polyethylenimine-superparamagnetic iron oxide nanoparticle labeled bone marrow mesenchymal stem cells in vitro].

OBJECTIVE: To explore the optimal concentration of polyethylenimine-superparamagnetic iron oxide (PEI2k-SPIO) particles for labeling bone marrow mesenchymal stem cells (BMSCs) in vitro, then to demonstrate the imaging characteristics of the cells by 7.0-T MR scanner. The lowest cell quantity and the optimal cell quantity detected on MR was observed. METHODS: Cells at 2nd passage were inoculated into the 6-hole plate with cover glass. The different concentrations of PEI2k-SPIO (5 microg/mL, 7 microg/mL, 10 microg/mL, 15 microg/mL, 20 microg/mL) were added into different holes, respectively. After labeled with different concentrations of PEI2k-SPIO, the Prussian blue stain was used for determining the labeling efficiency. MTT growth curves were used to identify the activity of BMSCs and to determine the optimal threshold of SPIO nanocomposite particles labeled the stem cells at different PEI2k-SPIO concentrations (7, 10, 15, 20 microg Fe/mL medium). To definite the lowest cells quantity and the optimal observable cells quantity on MR imaging, 1 x 10(6), 1 x 10(5), 1 x 10(4) and 1 x 10(3) cells labeled with optimal threshold of PEI2k-SPIO and 1 x 10(6) cells unlabeled suspended in 0.2 mL agarose (10 g/L), respectively undergone MR scan. RESULTS: MTT growth curves showed the optimal threshold of PEI2k-SPIO labeled BMSCs was 7 microg/mL, which indicates has no adverse effects on the growth of stem cells. At the opimal concentration (7 microg Fe/mL), the lowest observable cell quantity of PEI2k-SPIO-labeled cells for MRI was 1 x 10(4), and the optimal observable cell quantity was 1 x 10(6). CONCLUSION: At the opimal concentration, adverse effect to stem cell activities had not be detected when were labeled with PEI2k-SPIO and the clearly image of MRI of labeled BMSCs could be obtained.

[The effect of basic fibroblast growth factor on angiogenesis and on the expression of basic fibroblast growth factor and vascular endothelial growth factor in acute infarcted myocardium].

OBJECTIVE: To evaluate the effect of intramyocardial administration of basic fibroblast growth factor (bFGF) on the angiogenesis and on the expression of bFGF and vascular endothelial growth factor (VEGF) in infarcted myocardium. METHODS: Twenty-four mongrel dogs were randomized into control group and therapeutic group. Acute myocardial infarction was made by ligation of the left anterior descending coronary artery distal to its first diagonal branch. After coronary artery was occlused, 50 micrograms of basic fibroblast growth factor in 15 ml of normal saline were injected into the infarcted myocardium and its border zone in therapeutic group, whereas the same volume of normal saline alone was used in control dogs. Every 3 dogs in each group was studied on the 1st day, the 3rd day, the 10th day and the 17th day after surgery respectively. With sensitivity encoded technique, cine MR was performed on each dog before euthanasia to evaluate the cardiac function. Angiogenesis and the expression of VEGF and bFGF were evaluated by immunohistochemical studies with factor VIII and the antibodies of VEGF and bFGF. RESULTS: In therapeutic group, left ventricular ejection fraction, improved markedly since the 10th day after injection of bFGF. Microvessel density was higher in the therapeutic group than in the control group except on the first day. VEGF and bFGF expressed more in the therapeutic group. CONCLUSION: Intramyocardial administration of bFGF is useful in increasing the growth of microvessels and improving the left ventricular function in acute myocardial infarction.