Effects Of Glucose On Barrier And Active Transportation Of Human Retinal Pigment Epithelium

ObjectiveRetinal pigment epithelium carry out several functions, such as outer blood-retina barrier, active transportation of fluid and ions, secretion of kinds of cytokines, etc. Among them, Barrier and active transportation has more close relationship with diabetic macular edema although there is possibility that all the functions affect the fluid balance around RPE directly or indirectly. So in this study effects of high glucose on transepithelial resistance(TER), permeability to horseradish peroxidase(HRP), expression of tight junction complex were evaluated.Method1 Confluent ARPE-19 cells cultured in Millicell HA inserts were used as outer blood-retina barrier model.2 After growing in DMEM/F12 medium contains different glucose for 1, 2, 3, 4 weeks, TER and permeability to HRP were mesured.3 Occludin, zo-1, N-cadherin, β-catenin, Cx43, Na-K-ATPase α₁ ,, Na-K-ATPase β₁ P2Y2 were tested by RT-PCR4 Western blot were used to determine the expression of occludin, β-catenin, Cx43 and Na-K-ATPase βResult1 About 2 weeks later ARPE-19 grown on Millicell HA inserts reach a constant level of TER which means a out blood-retina barrier model were established.2 Cells in medium contains different glucose has different TER. TER of cells in medium contains 16mmol/L glucose has no significant difference with control group which has 7mmol/L glucose. But for cells in medium contains 30mmol/L glucose, TER fluctuate obviously. On the first and second week TER reach a high level that has much significant difference compare with control group, P<0.001; after that, TER decrease gradually. On the fourth week, there this no statistic difference between them.3 Permeability of treated cells to HRP changed significantly compare with control group. P<0.05.4 RT-PCR reveal that high glucose modulate the tested factors differently. P2Y2, occludin, N-cadherin, Cx43, Na-K-ATPase α₁ , has similar changes. First the expression were up regulated. Later in medium contains 30mmol/L glucose , the expression of the these factors...