Effect of taurine on GFAP and TauT expressions in rat retinal Müller cells in high glucose culture

Objective： To detect the expression of glial fibrillary acid protein （GFAP） and taurine transporter （TauT） in the retinal Müller cells in high glucose culture with taurine and to explore the influence of glucose on the taurine transporting, and the possible protective effects of taurine on MUller cells in early diabetic retinopathy. Methods： The Müller cells from the rat retina were cultured in high glucose, and GFAP and Taut expressions were detected in the cells treated with different doses of taurine by immuocytochemical fluorescein staining and Western blotting. Results： High glucose enhanced the expression of GFAP and decreased the expression of TauT in Müller cells. Taurine decreased the up-regulation of GFAP in the cells which was induced by high glucose; 0. 1-10 mmol/L taurine increased the expression of TauT in Müller cells. Conclusion： Taurine can inhibit the changes in Müller cell resulted from high glucose.

DYSFUNCTION OF MYOCARDIAL AND VASCULAR TAURINE TRANSPORT IN L-N~ω-NITRO-ARGININE-INDUCED HYPERTENSIVE RATS

Objective.To study the change of taurine transport,and taurine transporter(TAUT)and cysteine sulfinate decarboxylase(CSD)mRNA contents in hypertension and hypertensive cardiomegaly.Methods.Taurine content was determined with a amino acid analyser.Taurine uptakes were deter-mined by( 3 H)-taurine incubation.The content of TAUT and CSD mRNA levels were measured by com-petitive quantitative RT-PCR in myocardial and vascular tissues of L-N ω -nitro-arginine(L-NNA)-in-duced hypertensive rats.Results.After the treatment of rats with L-NNA for28days,myocardial and vascular taurine con-tents decreased by11%and15%(P<0.05),respectively,and plasma taurine level increased by13%(P<0.05).Myocardial and vascular Vmax of taurine uptake reduced by30%and19%(P<0.05),respec-tively.Their Km of taurine uptake increased by36%and17%(P<0.05).Myocardial and vascular TAUT mRNA content decreased by22%and19%(P<0.05),respectively,but CSD mRNA content increased by22%(P<0.05)and30%(P<0.01),respectively.Conclusions.This study suggests that there is a decreased taurine content in myocardial and vascu-lar tissues of L-NNA-induced hypertension rats.The decreased taurine content may result from the de-creased number of TAUT on the cell membrane mainly due to the down-regulation of TAUT gene and TAUT affinity caused by hypertension and hypertensive cardiomegaly.