Department of Biomedical Engineering, The City College of the City University of New York, 138th Street at Convent Avenue, New York, NY 10031, USA.
Ann Biomed Eng. 2010 Apr;38(4):1463-72. doi: 10.1007/s10439-010-9920-x. Epub 2010 Jan 20.
Charge carried by the surface glycocalyx layer (SGL) of the cerebral endothelium has been shown to significantly modulate the permeability of the blood-brain barrier (BBB) to charged solutes in vivo. The cultured monolayer of bEnd3, an immortalized mouse cerebral endothelial cell line, is becoming a popular in vitro BBB model due to its easy growth and maintenance of many BBB characteristics over repeated passages. To test whether the SGL of bEnd3 monolayer carries similar charge as that in the intact BBB and quantify this charge, which can be characterized by the SGL thickness (L(f)) and charge density (C(mf)), we measured the solute permeability of bEnd3 monolayer to neutral solutes and to solutes with similar size but opposite charges: negatively charged alpha-lactalbumin (-11) and positively charged ribonuclease (+3). Combining the measured permeability data with a transport model across the cell monolayer, we predicted the L(f) and the C(mf) of bEnd3 monolayer, which is approximately 160 nm and approximately 25 mEq/L, respectively. We also investigated whether orosomucoid, a plasma glycoprotein modulating the charge of the intact BBB, alters the charge of bEnd3 monolayer. We found that 1 mg/mL orosomucoid would increase SGL charge density of bEnd3 monolayer to approximately 2-fold of its control value.
脑内皮细胞表面糖萼层 (SGL) 所携带的电荷已被证明可显著调节血脑屏障 (BBB) 对体内带电荷溶质的通透性。bEnd3 是一种永生化的小鼠脑内皮细胞系，其培养的单层正在成为一种流行的体外 BBB 模型，因为它易于生长并且在多次传代过程中保持许多 BBB 特性。为了测试 bEnd3 单层的 SGL 是否携带与完整 BBB 相似的电荷，并量化这种电荷，可以用 SGL 厚度 (L(f)) 和电荷密度 (C(mf)) 来表示，我们测量了 bEnd3 单层对中性溶质和大小相似但带相反电荷的溶质的溶质通透性：带负电荷的乳白蛋白 (-11) 和带正电荷的核糖核酸酶 (+3)。将测量的渗透数据与跨细胞单层的转运模型相结合，我们预测了 bEnd3 单层的 L(f) 和 C(mf)，分别约为 160nm 和 25mEq/L。我们还研究了是否存在一种调节完整 BBB 电荷的血浆糖蛋白——粘蛋白，会改变 bEnd3 单层的电荷。我们发现，1mg/mL 的粘蛋白可将 bEnd3 单层的 SGL 电荷密度增加到对照值的约 2 倍。
