Expression of P-glycoprotein/caveolin-1 in blood-brain barrier
AIM:To identify the site of cellular expression of P-gp in human brain in situ and to morphologically determine whether an association may exist between P-gp and caveolin-1. METHODS:The glioma animal models was established, halves of the tumor-free samples were immersed in a fixative mixture consisting of 40 g/L paraformaldehyde. The latter procedure consisted of intraoperative examination of hematoxylin-eosin (H&E) -stained, as well as immunohistocheroical staining was used to prove their biological characteristics. The other halves of the sections were subjected to double labeling for the P-gp (TRITC labeled) and for the caveolin-1 (FITC labeled). The location and characteristics of expression of the two proteins in the BBB was observed by laser scanning microscope. RESULTS :①P-gp labeling appears concentrated in the luminal compartment of the endothelial cells and also marks a foot process of gliocyte. ②Caveolin-1 stains the entire endothelial cytoplasm, with fine puncta in the luminal compartment and larger, intensely immunoreactive puncta in the abluminal compartment. ③The merged images show P-gp and caveolin-1 co-expression (yellowish fluorescence): the two proteins co-localize either in the luminal endothelial compartment or at the border of the luminal/abluminal compartments. CONCLUSION: P-gp marks the BBB that the transporter is localized in the luminal endothelial compartment, where it co-localizes with caveolin-1. The demonstration of this co-localization of P-gp with caveolin-1 contributes a morphological backing to biochemical studies on P-gp/caveolin-1 relationships and leads us to suggest that interactions between these molecules may occur at the BBB endothelia.
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万方数据
维普
