Construction And Targeted Imaging Experimention Of Lipid Microbubbles Ultrasound Contrast Agent Binding With Sialyl Lewis~x

PARTⅠCONSTRUCTION OF ULTRASOUND CONTRASTAGENT BINDING WITH SIALYL LEWISXANDTARGETING STUDY IN VITROObjective To prepare a kind of targeted lipid microbubblesultrasound contrast agent binding with sialyl lewis~xand to investigate itsaffinity in vitro.Method The lipid ultrasound microbubbles carried with sialyl lewis~xwere prepared using “biotin-avidin” bridging method.The physicalcharacteristic of targeted microbubbles and the combination were valued bylight microscopy and confocal laser scanning microscopy. To build a modelof human umbilical vein vascular endothelial cel（lHUVEC） inflammationstimulated by tumor necrosis factor（TNF-α） and to detect the p-selectinexpression of HUVEC by immunofluorescent assay. The targetedeffectiveness of microbubbles with HUVEC were observed using light microscopy.Results Antibody with microbubbles have an efficient connectionand the rate was93.93%. The targeted microbubbles size distribution wasuniform and the average particle size was1.63±0.23μm.There were nosignificant adhesion and aggregation for two types microbubbles.Comparewith non-targeted microbubbles,the appearance had no significantdifference.Mass of p-selectin expressed on the surface of cell and in thecytoplasm for stimulated HUVEC.There were no lipid microbubbles bindto HUVEC in the three control groups，and plenty of microbubbles carriedwith sialyl lewis~xstick to stimulated HUVEC surface.Conclusions microbubbles carried with sialyl lewis~xwere preparedsuccessfully and can bind to stimulated HUVEC surface in vitro.Combination was efficiency and specific.This is animal vascular ultrasoundmolecular imaging basis for early inflammatory lesions. PART Ⅱ ANIMAL EXPERIMENT OF ULTRASOUNDCONTRAST AGENT WITH SIALYL LEWISXFORTARGETED CONTRAST-ENHANCEMENT IMAGING INVIVOObjective To evaluate the contrast-enhancement effect of theprepared targeting ultrasound contrast agent with sialyl lewisx(MBs) forvascular intima inflammation.Methods Two types of ultrasound contrast agents, one withbiotinylated lipid microbubbles（MBb）, the other with sialyl lewisxtargeting microbubbles(MBs), were prepared using mechanical oscillationmethod, and the connection was observed by confocal laser fluorescencemicroscope. Models of rats with abdominal aortic intima inflammationinjury were created by balloon mechanical strain surgery in the rats’femoral arteries, and P-selectin expression on the injured vascular intimawas detected immunohistochemically. Sixteen SD rats weighting between350g to400g were randomly divided into two groups. Before and after thesurgeries, the two groups of rats were injected respectively via tail veinswith MBb and MBs contrast agents for comparison under ultrasoundinspection, the characteristics and contrast-enhancement effects of the twotypes of contrast agents were compared using DFY quantitative diagnosis.Results The targeting ultrasound contrast agent with sialyl lewisxand models of rats with abdominal aortic intima inflammation injury weresuccessfully prepared. Mass of P-selectin expression on the injuredvascular intima was detected immunohistochemically. Before modeling,there was no distinct difference in contrast-enhancement effect between the two types of contrast agents. After modeling, the targeting contrast agent,as compared with the ordinary type, however, produced more significantlyenhanced video intensity and longer time of imaging (P<0.05).Conclusions ultrasound contrast agent with sialyl lewisxcanspecifically bind to P-selectin expressed in vascular endothelial cell surface.It is expected to be used as tool for detection of early inflammation causedby artery atherosclerotic disease for its good ability of targeted-adhesionand contrast-enhancement.