气管滴注^(99m)Tc-C_(60)(OH)_x大鼠的SPECT显像观察

SPECT observation of biodistribution of ^(99m)Tc labeled C_(60)(OH)_x in rats after

为了解C_(60)(OH)_x经呼吸道进入体内后的分布情况,用放射性标记技术和单光子发射计算机断层(Single photon emission computed tomography,SPECT)成像技术,研究了^(99m)Tc-C_(60)(OH)_x经气管滴注后在SD大鼠体内分布、吸收和代谢的情况,及其与纳米颗粒粒径的依赖关系。用^(99m)Tc标记了富勒烯多羟基衍生物C_(60)(OH)_x(x=22,24),标记率为93%。标记物在体外和体内都有良好的稳定性。比较了^(99m)Tc-C_(60)(OH)_x和Na^(99m)TcO_4经气管滴注后在SD大鼠体内的SPECT成像。结果表明,与水溶性的小分子Na^(99m)TcO_4不同,纳米尺度的^(99m)Tc-C_(60)(OH)_x标记物大多滞留于肺中,且清除缓慢;少部分^(99m)Tc-C_(60)(OH)_x能迅速通过肺泡-毛细管屏障进入血液,主要分布于肝、骨和脾中,并通过肾代谢排泄,显示了纳米颗粒生物分布的主要特征。由此可见,纳米颗粒穿越气血屏障的能力与颗粒物的粒径相关。研究结果为纳米颗粒的呼吸毒性研究提供了重要基础资料。

Biodistribution of nanomaterials after lung exposure will be helpful to gaining an insight into the pulmonary toxicity. To observe distribution of C60（OH）x after lung exposure, radiolabel technique and single photon emission computed tomography （SPECT） imaging was used in this experiment. The biodistribution of ^99mTc-C60（OH）x in Sprague-Dawley （SD） rats after intratracheal instillation was studied. C60（OH）x （x=-22,24） were labeled with ^99mTc and the radiolabeling yield of ^99mTc-C60（OH）x was greater than 93%. The ^99mTc-C60（OH）x showed a high stability both in vivo and in vitro. Biodistributions of Na^99mTcO4 or ^99mTc-C60（OH）x in SD rats after intratracheal instillation were observed by SPECT imaging. Unlike the distribution of Na^99mTcO4, a large proportion of the ^99mTc-C60（OH）x was retained in lung, while a small amount of ^99mFc-C60（OH）x penetrated the alveolar-capillary barrier, diffusing into circulation promptly after I.T. and distributing mainly in the liver, bone and spleen, a significant character of biodistribution of nanomaterials. It seems that the ability of crossing over the alveolar-capillary barrier is dependent on size of the nanomaterials. The results provide valuable data for pulmonary toxicological study of nanomaterials.