Figure 5. Vectorial 3H-cholesterol transport in primary bovine mammary epithelial (MeBo) cells. A: Time-dependence of the trans-epithelial electrical resistance of MeBo cells grown as monolayer in Transwell® tissue culture plates. MeBo cells were exposed to DMEM-F12 medium supplemented with 10% fetal calf serum and 1% antibiotics/antimycotics that was added to the apical and basal chambers.
Resistance was measured according to the manufacturer’s instructions in quadruplicates of >12 wells. Trans-epithelial electrical resistance was calculated according to [41]. B: Vectorial apoA-I mediated 3H-cholesterol efflux in MeBo cells. The experiment was performed according to the optimized protocol (loading 1h, equilibration 1h, efflux 1h). All other details of the procedure were as described in Figure 4B. ApoA-I was added either to the apical (A) or to the basal (B), or to both chambers (A’, B’). ApoA-I mediated cholesterol efflux was calculated separately for the apical and the basal chamber by subtracting the background efflux. All data are expressed as means ± SD of triplicates measurements.