about the permeability assay using caco-2 - (May/01/2006 )

Hi, I am trying to do permeability experiment using caco-2 cell. The pH of the medium people used are different in the papers. Some people use 7.4, others use 6.8. So, do anyone know which pH is better and why? I am still confuse about the drug transport assay using caco-2. Drug and nutrient are usually absorbed by small intestine, but caco-2 is from the colon (large intestine), so why most of papers use caco-2 for the transport experiment, not use small intestine cell line.
thanks

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As good as I know pH differences on apical and basal side can be used to simulate natural pH gradient in small intestine.

Caco-2 are colon by origin but as I heard - are enough similar to small intestine to use as model.

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Thank your for your reply.
But usually, people use the same pH on the apical and basal side. If use different pH on different sides, which side use the higher pH and what pH was used? Also, most paper used DMEM for caco-2, but ATCC recommend to use MEM. So, do anybody know what is the different effect of these two medium on the Caco-2 cells? I grow caco-2 on the 24-well insert, after 20 days, the cell resistance reach about 1500 ohm, is it too high?
thanks

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I'm not sure, never done that. Basic knowledge and logic would suggest to use lower pH on apical side.

Try rather to compare formulation of ATCC MEM and DMEM used by the others - maybe it's same thing with different name.

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