固体脂质纳米粒在上皮单层细胞上的转运机制

Transport properties of solid lipid nanoparticles across MDCK cell monolayers

目的:探讨固体脂质纳米粒(SLN)在犬肾上皮单层细胞(MDCK)上的转运机制。方法:以硬脂胺-异硫氰基荧光素为标记物,以单硬脂酸甘油酯为脂质材料,用溶剂扩散法制备荧光标记SLN,考察各因素对SLN跨MDCK单层转运的影响。结果:当SLN脂质浓度从50 mg.L-1增加到400 mg.L-1,表观渗透系数Papp值从最高点的56.1×10-6 cm.s-1逐渐下降并维持在20×10-6 cm.s-1左右,同时SLN从单层细胞顶侧向基底侧的转运能力基本高于相反方向。pH的降低和无荧光空白SLN的加入,使Papp减小了30%～50%;而低温及秋水仙素的干扰更使Papp降低至对照的30%。结论:SLN在MDCK细胞单层上的跨膜渗透并不是单一的主动或被动模式,而是细胞内吞的主动转运和细胞层脂质通道被动扩散相结合,顶侧向基底侧转运时主动方式占主导,相反方向时被动方式占主导。

OBJECTIVE To investigate the transport properties of solid lipid nanoparticles （SLN） across MDCK monolayers. METHODS SLN was prepared by aqueous solvent diffusion method, and otcadecylamine-fluorescein isothiocyanate was synthesized and used as a fluorescence marker to be incorporated into SLN. The transport of SLN was carried out under various conditions. RESULTS The apparent permeability coefficient （Papp） of SLN declined from 56. 1 ×10^-6cm·s^-1 to 20 ×10^-6 cm ·s^-1 when the lipid concentration of SLN increased from 50 mg·L^-1 to 400 mg·L^-1 , and the permeability of SLN from apical to basolateral side was higher than that from basolateral to apical side. Meanwhile,Papp was reduced by the change of pH and the addition of blank SLN obviously,and a lower temperature or colchicines could also decrease Papp of SLN, about 30% of control. CONCLUSION SLN could cross MDCK monolayers by the combined action of active transfer with cellular endocytosis and passive diffusion channels for lipid. Active transfer predominated when SLN transport from apical to basolateral side,and passive diffusion was the main path from the other side.