Dietary Taurine Supplementation Prevents Glial Alterations in Retina of Diabetic Rats

The preventive effect of dietary taurine supplementation on glial alterations in retina of streptozotocin-induced diabetic rats was examined in this study. Blood glucose content, content of taurine, glutamate and < gamma >-amino butyric acid (GABA) and expression of glial fibrillary acid protein (GFAP), vascular endothelial growth factor (VEGF), glutamate transporter (GLAST), glutamine synthetase (GS) and glutamate decarboxylase (GAD) in retina were determined in diabetic rats fed without or with 5% taurine in a controlled trial lasting 12 weeks, with normal rats fed without or with 5% taurine served as controls. Dietary taurine supplementation could not lower glucose concentration in blood (P > 0.05), but caused an elevation of taurine content and a decline in levels of glutamate and GABA in retina of diabetic rats (P < 0.05). The content of GABA in normal control group was not altered by taurine supplementation. With supplementation of taurine in diet, lower expression of GFAP and VEGF while higher expression of GLAST, GS and GAD in retina of diabetic rats were determinated by RT-PCR, Western-blotting and immunofluorescence (P < 0.05). GFAP, VEGF, GLAST, GS and GAD expressions in normal controls were not altered by taurine treatment. This may have prospective implications of using taurine to treat complications in diabetic retinopathy.