Study On The Intestinal Carotenoids Uptake In Vitro

This article aimed to further explore the absorption mechanism of the carotenoids. An in vitro cell primary culture systerm was established. Under conditions simulating the intestinal environment of bovine and chicken, carotenoids uptake characterization of two kinds of intestinal epithelial cells were explored.In the first experiment, Isolation of the epithelial cells and preservation of perfect intestinal villus and crypt cell clumps were achieved using a mixture of tripsin and EDTA. Cutures were used for experiments between 11-14 days postconfluency, because cultures of intestinal epithelial cells exhibit maximum differentiation at this stage by alkaline Phosphatase staining. This experiment provided a feasible method for primary culture of intestinal epithelial cells, and the cells abtained in this way can be used for relative experiment research.In the second experiment, the celluar uptake ofβ-carotene and lutein were time-dependent, saturable process. Celluar accumulation of micellesβ-carotene and lutein were proportional to the media content of carotenoids at≤2.5 umol/L. Cellularβ-carotene and lutein content increased in a curvilinear manner when cultures were incubated in micellar medium containing 3 to 27 umol/L. Cellular carotenoids content were maximum when micellar carotenoids were≥18 umol/L.The third experiment's result showed: Bovine and chicken IEC show specific selective uptake ofβC and lutein.β-carotene and lutein uptake in chicken IEC were significantly higher than that in bovine IEC (p<0.01); The preferential accumulation ofβC in both bovine and chicken IEC compared with lutein from micellar medium were found.βC content of bovine and chicken IEC was significantly higher than that of lutein when carotenoids concentration were 1uM, 1.6uM and 2.2uM (p<0.01), and in the same concentration (0.5-27uM), uptake amount of 3 C was 1.3-2 time higher than that of lutein; Under linear concentration conditions at 16 h incubation, The uptake rate ofβC and lutein in bovine IEC were 10.1±1.8% and 7.1±0.5%, but the extent of uptake of the two carotenoids in chicken IEC were 12.2±1.1% and 8.9±0.6%.In the last experiment, there was no indication that high levels ofβC (or lutein) in medium negatively affect lutein (orβC) accumulation. Along with the raising concentration ofβC (or lutein) in micellar medium, the celluar content of LUT (orβC) in bovine and chicken IEC gradually elevated. The cellular LUT (orβC) content was significantly increased (p<0.01) in cultures incubated in medium containing 24umol/LβC (or LUT). Additionally, cellular accumulation of micellar LUT (orβC) was not affected (p>0.05) by high levels of intracellularβC (or LUT).