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目的量化CT阳离子型对比剂(CA4+)和阴离子型对比剂(碘可酸)对离体软骨组织中的葡萄糖氨基葡聚糖(GAGs)的亲和力,探讨CA4+和碘可酸在活体兔模型内的扩散动力学。材料与方法所有活体操作已获机构动物保护和使用委员会批准。使用微型CT扫描经每种对比剂进行过一系列平衡稀释的骨软骨块(牛的骨软骨块6块),利用改性结合实验来量化CA4+和碘可酸对GAGs的亲和力。向5只新西兰白兔的膝关节腔内注射对比剂,确定CA4+和碘可酸在活体的扩散动力学和对软骨组织的显示能力。利用非线性混合效应模型,研究对比剂在活体股骨沟软骨组织处的扩散动力学和骨软骨块摄取对比剂的能力。利用Studentt检验比较对比剂的扩散时间常数(τ)。结果软骨组织中被摄取的CA4+其储层浓度稳达100%,但碘可酸只有59%。在活体内,经两种对比剂增强的软骨组织均可获得稳定的CT衰减系数,CA4+和碘可酸在其内的τ值分别为13.8min和6.5min(P=0.04)。经CA4+(12mgI/mL)增强的软骨组织较易与周围组织区分,相对地,即使在较高浓度下(80mgI/mL),经阴离子型对比剂增强的软骨组织显示效果较差。结论鉴于阳离子型对比剂CA4+对GAGs的亲和力,可以获得与活体兔软骨一样的高质量的离体牛、兔软骨块的影像。
Objective To quantify the affinity of CT cationic contrast agent (CA4 +) and anionic contrast agent (Iodoconic acid) for glucosaminoglycans (GAGs) in isolated cartilage tissue and to explore the relationship between CA4 + and Iodoconic acid in vivo rabbit models Diffusion dynamics. Materials and methods All living practices have been approved by the Agency Animal Protection and Use Committee. A series of balanced dilutions of osteochondral (Cattle cartilage blocks 6) were performed on each contrast agent using a mini-CT scan and the binding affinity of CA4 + and Iodoic acid to GAGs was quantified using a modified binding assay. Five New Zealand white rabbits were injected intracavitary contrast agent into the knee joint to determine the diffusion kinetics and cartilage tissue display ability of CA4 + and Iodoic acid. The non-linear mixed-effects model was used to study the diffusion kinetics of contrast media at the living femoral furrow cartilage tissue and the ability of osteochondral cartridges to absorb contrast media. Contrast diffusivity time constant (τ) was compared using Student’s t test. Results The CA4 + uptake in cartilage tissue was 100% stable, but only 59% of iodic acid. In vivo, a stable CT attenuation coefficient was obtained for both cartilage tissue reinforced with both contrast agents with τ values of 13.8 and 6.5 min (P = 0.04) for CA4 + and Iodocoyl respectively. Cartilage tissue enhanced with CA4 + (12 mgI / mL) was more likely to differentiate from surrounding tissues, whereas cartilage tissue enhanced with anionic contrast agent showed poorer performance even at higher concentrations (80 mgI / mL). Conclusion Due to the affinity of cationic contrast agent CA4 + to GAGs, the same high quality images of isolated rabbit and rabbit cartilage can be obtained.