The expression of P-gp in the interstitial cells was related to the distance of the cells from the capillary wall. The nearer the cell was to the capillary wall, the stronger the expression of P-gp (Fig 1c). Table 3 Expression of the 5 multidrug resistance proteins in the interstitial cells Multidrug resistance protein n – + ++ +++ Strongly positive rate(%) P-gp 30 3 13 10 4 46.67 Topo II 30 21 3 2 4 20.00 GST-π 30 13 14 2 1 10.00 MRP 30 24 4 1 1 6.67 LRP 30 buy Bafilomycin A1 22 6 1 1 6.67 The expression of resistance proteins in interstitial cells are similar to the tumor cells. The positive expression of P-gp is highest, the Combretastatin A4 difference was statistically significant (Rank sum test, P < 0.05) Expression of
the 5 multidrug resistance proteins in different grade tumors In tumor cells and interstitial cells, there was no significant difference between the expression of the 5 multidrug resistance proteins (Fisher definite probability methods, P > 0.05) between high grade
and low grade tumors (Tab 4). In the capillary vessels, the strong find more positive expression of P-gp was 60% (6/10) in high grade and 10% (2/20) in low grade tumors. This difference was statistically significant (Fisher definite probability methods, P < 0.05) (Tab 4), which shows that the P-gp positive rate in high grade tumors is higher than in low grade tumors and in capillary vessels. Table 4 Positive expression of the 5 multidrug resistance proteins in the different grades of brain tumors Multidrug resistance proteins Tumor cells Capillary vessels Interstitial cells H L P H L P H L P n 10 20 - 10 20 - 10 20 - P-gp 4 3 0.378 6 2 0.027 8 19 0.251 Popo 4 4 0.384 0 0 - 0 0 - GST 3 2 0.3 0 0 - 8 14 0.682 MRP 0 0 - 0 0 - 2 2 0.584 LRP 0 0 - 0 0 - 2 2 0.584 In tumor cells and interstitial cells, there was no significant difference between Alanine-glyoxylate transaminase the expression of the 5 multidrug resistance proteins (Fisher definite probability methods, P > 0.05) between high grade and low grade tumors. In the capillary vessels, the strong positive expression of P-gp was 60% (6/10) in high grade and 10% (2/20) in low grade tumors. This
difference was statistically significant (Fisher definite probability methods, P < 0.05). Double P-gp/caveolin-1 immunolabel On the double P-gp/caveolin-1-immunolabeled samples, observation of sections at higher magnification on serial optical planes of cross-sectioned microvessels confirmed that the expression of P-gp corresponded to the endothelial cells and also revealed that the transporter is localized in the luminal compartment of endothelial cells (Fig 2b and Fig 2f). Unlike P-gp, caveolin-1 stained the entire thickness of the endothelium from the luminal to the abluminal side with a finely punctate pattern in the endothelial luminal compartment and larger fluorescent puncta in the abluminal luminal compartment (Fig 2c and Fig 2g).