Experimental MRI study of targeting Rho-associated protein kinase 1 to detect plaques in atherosclerosis
Objective:To observe the expression of Rho-kinase(ROCK)1 in atherosclerotic plaques,to synthesize a ROCK1-targeted probe and characterize it,then explore its ability to visualize atherosclerotic plaques.Materials and Methods:The ROCK1 antibody was coupled with ultra-small superparamagnetic iron oxide nanoparticles to prepare the targeting probe(Fe3O4@PEG-ROCK1),which was characterized and analyzed.Apolipoprotein E knockout(ApoE-/-)mice were fed with high-fat diet and five mice were selected randomly at 10,16,22,28,and 34 weeks,respectively,to measure weight.The expression and activity of ROCK1 were observed by ROCK1 immunostaining and western blot.ApoE-/-mice fed for 34 weeks were divided into two groups,one group(n=10)was injected with Fe3O4@PEG,the other group(n=10)was injected with Fe3O4@PEG-ROCK1.Magnetic resonance imaging was performed before and 8 h and 16 h after injection of the nanoprobe,and the signal intensity of plaques was calculated by Image J software.Abdominal aortic specimens were analyzed by pathology.Results:Fe3O4@PEG and Fe3O4@PEG-ROCK1 were uniformly dispersed in aqueous solution,and the hydrated particle sizes were(27.06±1.52)nm and(30.52±2.95)nm,respectively.The Zeta potential was(-35.18±0.31)mV and(-16.60±3.26)mV,respectively.Fe3O4@PEG-ROCK1 could reduce the phagocytosis and clearance of macrophages,was non-toxic within a certain concentration range,and maintains immune activity.The saturation magnetization(0.0868 T)and T2 relaxation rate(162.3 mM-1s-1)indicated that Fe3O4@PEG-ROCK1 had good magnetic sensitivity.With advancing atherosclerosis,the expression of ROCK1 increased(r=0.959,P<0.001).The activity of ROCK1 in abdominal aorta of ApoE-/-mice was higher than that of C57BL/6 mice(0.30±0.02 vs.0.24±0.02,P<0.01).The results of magnetic resonance imaging showed that compared with plain scan(the plaque signal of Fe3O4@PEG group and Fe3O4@PEG-ROCK1 group were 8.25±1.39 and 7.81±3.22,respectively).After the injection of the probe,the plaque signal of the two groups decreased.Compared with the Fe3O4@PEG group,the plaque signal of the target probe Fe3O4@PEG-ROCK1 group decreased more significantly(8 h,5.37±1.79 vs.3.91±2.26,P=0.001;16 h,6.68±2.39 vs.4.61±2.80,P=0.001).Prussian blue staining revealed the deposition of nanoprobes within the plaques,corresponding to the positive areas of immunohistochemistry.Conclusions:ROCK1 is highly expressed and active in atherosclerotic plaques.Fe3O4@PEG-ROCK1 may be used as an effective magnetic resonance contrast-enhancing agent for the non-invasive detection of atherosclerotic plaques to promote the visual detection of plaques.
国家科技期刊平台
NSTL
万方数据
维普
