Effect And Mechanism Of Nano-alumina On The Permeability Of Blood-Brain-Barrier Model In Vitro

[Objective] To evaluate the effect of nano-alumina on the permeability of blood brain barrier (BBB) and discuss the possible transport way of nano-alumina.[Methods]1. Investigation of the dispersion of50nm nano-alumina.(1) The diameter and electric charge of nano-alumina was measured by Nano-ZS90particle size analyzer.(2) The characterization of alumina nanoparticles was performed by electron microscopy.2. Building BBB model in vitro.(1) Brain capillary endothelial cells (BCECs) and astrocytes were isolated from brain of newborn (1-3days) Wistar rats and immunocytochemically stained separately.(2) The model of BBB in vitro was built with co-culture of BCECs and astrocytes on Transwell, and its efficiency was tested.3. The measument of effect of nano-alumina on the permeability of blood brain barrier (BBB):(1) BBB were exposed to50nm nano-alumina at the concentrationes of0.0125mg/ml,0.025mg/ml and0.05mg/ml. Comparison of the permeabilities to rutin of BBB before nano-alumina exposure and after exposure was performed.(2) BBB were exposed to50nm nano-alumina at the concentration of0.05mg/ml and cultured for0h,2h,4h,6h and8h respectively, comparison of the permeabilities to rutin of BBB among these groups for different cultivation time was performed.4. The measurement of possible transport way of nano-alumina:(1) BBB were exposed to50nm cy5.5-marked nano-alumina and cultured for0h,2h,4h,6h,8h and12h respectively, the numbers of cy5.5-marked nano-alumina were compared each other among these groups for different cultivation time.(2) BBB were exposed to50nm cy5.5-marked nano-alumina at the concentrationes of0.025mg/ml,0.05mg/ml. The numbers of cy5.5-marked nano-alumina were compared each other between two groups.(3) BBB were exposed to50nm cy5.5-marked nano-alumina and incubated at4℃and37℃. The numbers of cy5.5-marked nano-alumina were compared each other between two groups incubated at different temperature.[Results]1. The characterization of50nm-alumina.(1) The distribution of nano-alumina was even, and the mean diameter of particles was149.2nm, and its electric charge was47.6mV.(2) The appearance of nano-alumina was spherical.2. The establishment of BBB model in vitro:the purity of brain capillary endothelial cells (BCECs) and astrocytes were greater than90%, and the BBB model functioned well.3. The effect of nano-alumina on the permeability of blood brain barrier (BBB):(1) The absorbance of rutin suggest that compared with0mg/ml nano-alumina, there was no significant difference between the group of0.0125mg/ml and0mg/ml, the permeability of BBB at the group of0.025mg/ml and0.05mg/ml increased significantly (P<0.05).(2) A significant increase was found in all groups for different cultivation time compared with the group cultivated at0h (P<0.05).4. The possible transport way of nano-alumina:(1) The absorbance of cy5.5-marked nano-alumina suggest that compared with0h, the number of nano-alumina at the group of6h,8h and12h increased significantly (P<0.05).(2) The significant increase was found in0.05mg/ml group compared with the0.025mg/ml (P<0.05).(3) The number of nano-alumina at the group of37℃increased significantly compared with4℃group (P<0.05).[Conclusion]1.There is a dose-effect and time-effect on the permeability of BBB induced by nano-alumina exposure.2. The possible transport ways of nano-alumina in BBB are both active transport and inactive transport.