量子点经嗅觉通道进入中枢神经系统的可视化过程

A visible process of transporting quantum dots to the central nervous system through the olfactory pathway

模拟纳米颗粒呼吸道暴露及鼻腔给药模式,给ICR雌性小鼠鼻腔滴注量子点溶液,用动物活体荧光成像系统和荧光显微技术观察小鼠鼻腔、嗅球及大脑等组织中量子点分布随时间的变化情况.动物活体荧光成像可见,鼻腔滴注量子点30min后,量子点溶液扩散到嗅球,2h后鼻腔荧光强度逐渐变弱,24h仅在嗅球部位仍有可见荧光.荧光显微镜观察组织切片可见,滴注30min时,量子点仅存于嗅球前端边缘,1h后进入嗅球,并向嗅球深层转移,24h后发现嗅球内量子点荧光变弱,并在大脑组织切片内观察到量子点荧光.结果表明,纳米颗粒可以经过鼻黏膜进入脑组织,分布于嗅球、大脑等部位.

To investigate the possibility of transportation of nanoparticles to the central nervous system directly through the olfactory pathway under respiratory exposure condition,ICR female mice were administered with the quantum dot solution using nasal drip simulating the respiratory exposure of nanoparticles.The process for the quantum dots passing through the olfactory pathway and entering into brain tissues was monitored with in vivo fluorescence imaging and fluorescent microscopy after slicing the tissues.In vivo fluorescence imaging shows that quantum dots located in the olfactory bulb after 30 min of exposure.The fluorescence of quantum dots in cavitas-nasi was gradually weakened after 2 h,and disappeared after 24 h,while it was still visible in the bulb.Observation of the tissue slice with fluorescence microscop shows that the quantum dots located in the anterior edge of the olfactory bulb after 30-min exposure,and entered into the interior after 1 h,then transferred into the deep part of the tissue.Quantum dot fluorescence appeared in cerebrum sections after 24 h of exposure,along with a fade-out in the olfactory bulb.The results indicate that quantum dots are transferred along the olfactory pathway to the central nervous system,thereby circumventing the blood-brain barrier,after nasal administration to the mice.