Effect of Shaoyao Gancao Tang on function and expression of P-glycoprotein in Caco-2 cells
Wang, Y.; Zhao, J.; Zhao, Y.; Li, C.; Yi, Y.; Liang, A.; Odd, G.N.
Zhongguo Zhong Yao Za Zhi 37(7): 991-996
2012
ISSN/ISBN: 1001-5302 PMID: 22792804 Document Number: 663499
To investigate the effect of Shao Yao-Gan Cao-Tang on function and expression of P-glycoprotein (P-gp) in Caco-2 cells. 3H-digoxin (Dig), a substrate of P-glycoprotein, was used as a probe to measure the P-gp-mediated drug efflux transport, which indicated the function of P-gp in Caco-2 cells, while Verapamil (Ver) was used as a positive P-gp inhibitor. P-gp expression in Caco-2 cells was tested by immunohistochemistry staining. Inhibition effect of SGT on P-gp-mediated drug efflux transport and P-gp expression were investigated. Dig was shown a positive absorption mode in Caco-2 cell monolayer, characterized as the ratio of apparent permeabilities (Papp) from basolateral side to apical side Papp (BL-->AP) and from apical side to basolateral side Papp (AP-->BL) of Dig was 27.07. Addition of Ver into Dig transport media significantly inhibited P-gp activity which was indicated by increasing the Papp (AP-->BL) of Dig by 3.82 times, whereas Ver had no significant effect on Papp (BL-->AP). SGT (at the concentrations of 1/25 IC5, 1/5 IC5, IC,) could promote Papp (AP-->BL) of Dig by 159.83%, 217.95% ,160.26%. Papp (AP-->BL) of Dig was mildly increased by 59.16%, 50.73% by SGT at 1/25 IC5, 1/5 IC, respectively. Immunohistochemistry staining showed that SGT inhibited the expression of P-gp of Caco-2 cells. SGT showed the potential inhibition to the function and expression of P-gp, leading to the increase absorption of P-gp's substrates.