Relationship of TN-C, MMP-9 and TGF-β1 with aorta atherosclerotic plaues in mice / 中华老年心脑血管病杂志

Objective To study the relationship of TN-C,MMP-9 and TGF-β1 expression with aorta atherosclerotic plaue stability in mice on long-term high fat diet.Methods Fifty male apo E/ mice on high fat diet served as an experimental group and 50 male C57BL/6 mice on basic diet served as a control group.The morphology of plaques was observed with HE staining and the expression of TN-C,MMP-9 and TGF-β1 was detected with immunohistochemical staining.Results The serum TC and LDL-C levels were significantly higher in experimental group than in control group at weeks 16,24,32 and 40 (P＜0.05).The serum TG level was significantly higher in experimental group than in control group at week 16 (P＜0.05) and was significantly lower in experimental group than in control group at week 40 (P＜0.05).With the lengthening of the feeding time,the plaque area,the ratio of plaque to lumen area,and the expression of TN-C and MMP-9 increased gradually,but the expression of TGF-β1 decreased gradually (P＜0.05).Conclusion The expression of TN-C,MMP-9 and TGF-β1 can show the stability of atherosclerotic plaques.

MRI application and molecular imaging during the course of restenosis / 中华放射学杂志

Objective To observe the formation process with 3.0 T MRI dynamically, and to discuss the feasibility of molecular imaging studies on restenosis. Methods The models were built with balloon (2.0 F) injury which were separated into restenosis group (n=48) and control group (n=48). Zero h, 24 h, 1 week, 2 week, 4 week and 8 week after surgery, 3.0 T MRI scanning (T1WI, T2WI, PDWI) was performed respectively, the vascular of injured side were obtained for HE staining to observe the pathological changes, to analyze the measurement of neointimal area (IA), intimal proliferation index (IHI), lumen area (LA) and stenosis rates, correlation between HE staining measurements and MR images were analyzed. Two weeks after the injury, the restenosis model of rats (n=8) and control rats (n=8) were injected ultrasmall superparamagntiec iron oxide (USPIO,1 mmol/kg) by tail vein, respectively. 3.0 T MRI scanning (T2WI) was underwent at 0 h and 24 h after injection, the change of the arterial wall T2 signal was quantitatively analyzed and the relative signal intensity (rSI) and relative change rate (rSIC) of the vessel wall were calculated. Reference to MRI images, corresponding line segments were taken for Perl's blue staining and immunohistochemically staining of macrophages. One-way ANOVA, Pearson and t test were used for statistical analysis. Results In the early?term (0 h,24 h), the wall and surrounding high signal organization boundary was not clear, there was no obvious morphological change of the lumen. In the medium?term (1, 2 week), signal of the injured wall increased with different extents, wall thickening and luminal narrowing was progressive, the inwall was coarse. In the later?term (4, 8 week) wall signal got slightly lower, wall thickness, lumen change were not significant, the wall area and LA were significantly associated with pathologic measurement result (r value were 0.978, 0.732; P0.05). rSI was 1.582±0.051 after the injection of USPIO, then 24 h after injection of USPIO, T2 signal of the vessel wall was reduced significantly, rSI was 1.260 ± 0.088, rSIC was (-20.249 ± 6.489) % with statistical difference (t value was 8.924,P0.05). Perl's staining combined with immunohistochemical staining confirmed that the iron particles were taken by the macrophage's phagocytosis just in the neointimal. Conclusion 3.0 T MRI is capable of demonstrating the vessel wall and lumen changes dynamically, and the measurements are correlated with pathological results. USPIO can be consumed by macrophages in the neointimal, resulting in T2 signal of the vessel wall decreased significantly.

MR imaging of the atherosclerosis and the expression of tenascin-C and CD68 in ApoE-/- mouse model / 实用放射学杂志

Objective To explore the feasibility of 7.0T MR scanner in mouse aorta atherosclerosis models.Visualising the TN-C in atherosclerotic plaque by immunohistochemistry and its correlation with CD68 to provide experimental basis for the feasibility of TN-C in targeted MRI.Methods ApoE-/- mice and wild type C57 mice were fed on high fat diet to establish aorta atherosclerosis model (n=10),the aorta were observed by MRI after 14 weeks.The aorta specimens were taken to stain with HE to observe the pathological changes.The plaque was stained with oil red O,anti-TNC and TN-C antibody respectively to observe the fat,CD68 and TN-C in plaque.Results 7.0 MRI showed the aortic wall of the experimental group was thicker,high signal on T1 WI and PDWI,and low signal on T2 WI after 14 weeks.The histopathlogic examination showed the intima was obviously thicker,and the lumen was ir-regulary narrow.Both of CD68 and TN-C were highly expressed in plaque,and the distribution of TN-C correlated with CD68.In the control group,no case showed hyper-signal in the vessel wall of aorta or narrow lumen by MRI,and the histopathlogy showed no for-mation of atherosclerotic plaque in the aorta.Conclusion Aorta atherosclerotic plaque can be established through high fat diet on ApoE-/- mouse,and 7.0 MR can successfully detect it.TN-C is high expressed in AS plaque and the expression is correlated with CD68,which may suggest that they may collaborate in the development of AS.Detecting TN-C could be useful for the further study of atherosclerotic plaque.

MR imaging of tropomyosin-4 antibody targeting synthetic phenotype vascular smooth muscle cells in vitro / 中华放射学杂志

Objective To isolate,culture,and identify the synthetic phenotype vascular smooth muscle cells (VSMC) and identify the specific marker protein (tropomyosin-4,TPM-4) of synthetic phenotype.To employ the immune molecular imaging technique to develop MRI of probe targeted with TPM-4 antibody VSMC in vitro.Methods The synthetic phenotype VSMC and endothelial cells (EC) were isolated and cultured in vitro,respectively.Immunocytochemistry (ICC) staining for α-smooth muscle actin (SMA) and Ⅷ factor was performed for cell identification,respectively.The high expression level of TPM-4 protein was tested by immunofluorescence double staining.The MRI molecular probe was built by chemical cross-linking,TPM-4 conjuncted probe (TPM4-USPIO) as the experimental group,IgG conjuncted probe (IgG-USPIO) as the negative group,unconjuncted probe (USPIO) as the control group,and PBS as the blank group.The synthetic VSMC were incubated with probes within experimental group,negative group,control group,respectively,and EC were incubated with experimental group as another control group.Prussian blue staining was employed to analyze the specific-targeting and MTT assay was used to test bioactivity of the probe under different concentrations (0,5,10,20,40 μg/ml) in vitro.7.0 T MRI scanner was used to detect the magnetic properties.With 7.0 T MRI scanner,the T2WI images of different probes labeled synthetic VSMC and different concentration gradient (1 × 103,5 × 103,1 × 104,5 × 104)TPM4-USPIO labeled cells were obtained and analyzed.T2 signal and MTT data among groups were compared using single factor analysis of variance (ANOVA) and LSD test.Results The synthetic phenotype of VSMC were isolated and cultured successfully,and the VSMC could express the TPM-4 protein.The synthetic phenotype VSMC had a high level of the protein expression.The probe was made successfully.The T2 relaxivity of TPM4-USPIO and IgG-USPIO were 0.0350 × 106,0.0316 × 106 mol/s,respectively,with high stability as USPIO (0.0292 × 106 mol/s).Prussian blue staining results showed that the experimental group probe could specifically bind to the synthetic VSMC.MTT results showed that iron concentration within 40 μg/ml or less had no effect on VSMC proliferation activity.The T2 WI of experimental group showed lower signal than the control group.The T2 relaxivity was (116.67 ± 2.08) ms,which was less than the control group [(217.67 ±2.52),(219.33 ±2.08)ms,respectively] and the blank group [(205.33 ± 1.53)ms](F =1670.43,P ＜ 0.01).The T2 relaxivity of the different concentration gradient labeled cells (1 × 103 、1 × 104 、1 × 105) were (184.33 ± 2.08),(169.67 ± 1.15),(116.67 ± 2.08) ms,respectively (F =684.35,P ＜0.01).No significant difference of the T2WI gradual signal dim was found between cells with the same order concentration(P ＞ 0.05).Conclusions The synthetic phenotype of VSMC can be obtained by PDGF-BB treatment.TPM4-USPIO probe is efficient,specific and targeted at combination with synthetic VSMC.The T2WI signal changed obviously under high field MRI scanner,which provides a new way for molecular imaging research.

A primary study on the phagocytic activity of Kupffer cells with superparamagnetic iron oxide particles enhanced MR imaging in a rat nonalcoholic steatohepatitis model / 中华放射学杂志

Objective To investigate the feasibility of using superparamagnetic iron oxide(SPIO)as MRI contrast agent to assess rat nonalcoholic steatohepatitis Kupffer cells(KC)function.Methods Twenty male SD rats were randomly divided into A and B groups,group A(n=10)was the experimental group fed high fat diet,group B(n=10)was the control group fed normal diet After 8 weeks,plain MR and SPIO enhanced MR were performed in all the rats.Blood lipids were measured,and HE and Perl's blue staining in all livers specimen was done.The related results of the staining were analyzed with t test Results Group A TC and TG levels[(6.58±1.25)and(1.53±0.23)mmol/L respectively]were significantly higher than group B[(1.64±0.22)and(0.55±0.14)mmol/L respectively](t=11.716 and 11.588,P＜0.01).Group A and B groups hepatic signal intensity decreased in all sequences after SPIO enhanced,but in group A the level of decline[(34.78±4.51)% and(60.38±3.49)% respectively]was less than group B[(64.96±2.42)% and(81.08±1.66)% respectively]on PDWI and T_1WI,and statistically significant differences(t=-18.451 and-16.240,P＜0.01)were found.In group A the ratio of signal intensity of liver to spleen(1.002±0.141,5.000±0.516,20.004±1.490 and 2.601±0.077 respectively)was more than group B(0.400±0.102,1.500±0.115,0.503±0.105 and-0.300±0.058)before and after contrast enhancement on PDWI,T_2WI,T_2~* WI andT_1WI(t=10.745,19.800,39.168 and 92.785,P＜0.01).Typical histological hepatic lesions of NASH were observed in group A,Perl's staining-positive particles in group A(2.33±0.50)were fewer than in group B(4)(t=-10.000,P＜0.01).Conclusion The high-fat diet induced model of SD rats was close to the human NASH and was easy to establish.Clinical application of SPIO enhanced MR successfully assessed the phagocytic activity of KC in the study,and it suggested that the pathogenesis of NASH was related to the decreased phagocytic activity of KC.

Dynamically observing carotid artery intimal injury in mice using 7T micro-MR imaging / 中华老年医学杂志

Objective To dynamically observe stenosis and wall thickness of carotid artery with endothelium injury in mouse using 7T micro-MR imaging in vivo. Methods A mouse model of carotid artery intimal injury was established by removing endothelium with a flexible wire. The lumen diameter, lumen area, wall thickness and wall area of the injured arteries were observed, and serial MR scanning was performed in different time points after operation. Results The injured arteries and perivascular parenchyma were clearly observed by MR imaging. Before and 1, 5, 10 and 15 days after artery injury, the lumen diameter were (0.57±0.07)mm,(0.41±0.19)mm, (0.44±0.10)mm, (0.43±0.10)mm and (0.47±0.11)mm respectively, and the lumen area were (0.30±0.06)mm2, (0.18±0.11)mm2, (0.18±0.06)mm2, (0.18±0.06)mm2 and (0.22±0.07)mm2. The thickness of artery wall was(0.23±0.12)mm, and the area of artery wall was (0.35±0.24)mm2 15days after artery injury. Conclusions Stenosis and wall thickening of carotid artery after the artery intimal injury of mouse can be dynamically observed on MR imaging in vivo.

Influence on bionomics of endothelial progenitor cells labeling with magnetic nanoparticles / 中华放射学杂志

Objective To explore the influence of home synthesize magnetic iron oxide (called Fe2O3-PLL) labeling on peripheral blood endothelial progenitor cells (EPCs) bionomics to provide experimental foundation for MR imaging ex and in vivo. Methods Fe2O3 was incubated with PLL for 2 hours to obtain a complex of Fe2O3-PLL. Rabbit peripheral blood mononuclear cells were isolated and EPCs were selected by adherence method. Fe2O3-PLL was used to label EPCs. Prussian blue stain and electron microscope was used for showing intracellular iron. MTT assay was assessed to evaluate the difference of growth curve between unlabeled and labeled with 25 mg/L Fe2O3-PLL. Flow cytometry was performed to analyze cell cycle, cell apoptosis and the expression of surface markers of labeled and unlabeled cells. Expressions of Enos, KDR and Vwf at Mrna levels among unlabeled and labeled EPCs were detected by real-time polymerase chain reaction. Calcium ion channel and membrane fluidity were observed and analyzed by laser confocal microscopy. Statistical analyses were used with ANOVA and t test. Results Almost 100% cells were labeled by Fe2O3-PLL, iron-containing vesicles were intracytoplasma. There was no statistical difference in cells growth curve, cell life cycle [(93.74±3.52)% ,(94.57±3.66)% ] and cell apoptosis rate(12. 89±1.81) %, (11.67±1.18) %) between labeling with Fe2O3-PLL at a concentration of 25 mg/L and unlabeled cells (t = 0. 283, P > O. 05 ; t = 0. 977, P > 0. 05). There was also no statistical difference in relative amount of Enos, KDR and Vwf at Mrna levels and the expression of sudace phenotypic markers (CD34, CD106, CD146 and KDR) between two groups (P > 0. 05). In addition,Labeling had little influence on calcium ion channel and didn't significantly alter cell membrane fluidity.Conclusions The rabbit peripberal blood EPCs can be effective labeled with Fe2O3-PLL and without significant influence on cells bionomics at a low concentration of 25 mg/L. Almost every cell can be labeled and the labeled cells can be used further.

MRI of the transplanted endothelial progenitor cells for prevent atherosclerotic plaque formation / 中华放射学杂志

Objective To evaluate the 1.5 T magnetic resonance imaging system to depict and track in vivo of magnetically labeled endothelial progenitor cells(EPCs),and to study the possibility for preventing the atherosclerotic plaque formation in New Zealand rabbit model of carotid arterial injury after transplantation.Methods New Zealand rabbit EPCs were isolated,confirmed,expanded and then incubated with home synthesized Fe_2O_3-PLL,Prussian blue stain was performed for showing intracellular irons.The model of carotid arterial injury was performed by 2.5F balloons,the group A of 8 rabbits received magnetically labeled EPCs,group B of 3 rabbits received fluorescent-labeled EPCs and the group C of 5 rabbits were given same volume saline injection after endothelial injury of the carotid artery.MR imaging and histology were performed and compared 4 days later for randomly chosen three rabbit,each from one of the three group;all the other rabbits were fed with high lipid diet and examed using MR imaging and histology after 15 weeks.Results Epcs labeling efficiency was more than 95% by Prussian blue stain, 4 days after transplantation of EPCs,only in group A,the injured endothelium of carotid artery had signal intensity loss in T_2 * WI,which were correlated well with the area where the most Prussian blue staining positive cells were found in histopathology analyses.The rabbits of group A and B which received EPCs transplantation exhibited fewer plaques formation than those of the group C(P