RESUMEN
BACKGROUND: Diabetic retinopathy is the common complications of diabetes mellitus. Taurine is free aminoacid with the mostly abundant content in retina, and it is the necessary nutrition factor for regeneration and development of retina. Deficiency of taurine will cause structural and functional change of retina.OBJECTIVE: To probe into the effect of taurine on the expression of retinal glial fibrillary acidic protein (GFAP) mRNA DESIGN: A randomized and controlled observation SETTING: Third Military Medical University of Chinese PLA MATERIALS: This experiment was carried out at the Third Military Medical University of Chinese PLA from March 2003 to December 2003.Totally 54 closed group SD rats, with body mass of 250 g, were chosen.The successful diabetic rat model were randomly divided into 6 groups: diabetic group of 1 month, taurine-treated diabetic group of 1 month, diabetic group of 2 months, taurine-treated diabetic group of 2 months, diabetic group of 3 months, taurine-treated diabetic group of 3 months, with 9 rats in each group. Another 15 rats were chosen homeochronously as normal control group.METHODS: The animals were raised in separate cages. They were free to access to food and water, and fasted for 12 hours before experiment. Streptozotocin was used to induce diabetes mellitus .When Tes-Tape showed urine glucose reached more than (+++), and blood glucose concentration of venous blood from tail measured ＞16.7 mmol/L, models were established successfully. Expressions of GFAP mRNA and protein were measured with immunohistochemistry, RT-PCR, Western blotting and other technical methods. The effect of taurine on retinal neurons and glial cells in rats with diabetes mellitus was observed.MAIN OUTCOME MEASURES: Expressions of GFAP mRNA and protein RESULTS: ① Immunohistochemical analysis showed that: When rats suffered from diabetes mellitus for 1 month, taurine can inhibit the immunoreactivity of GFAP. With the elongation of intervention time of taurine, the immunoreactivity of GFAP is weakened. ②RT-PCR detection: Starting from the beginning of 2 months, the expression of GFAPmRNA in diabetic group began to increase; taurine obviously down-regulated the expression of GFAP mRNA. ③ In taurine-treated diabetic group of 3 months,the expression of GFAP was the strongest. When diabetic rats were treated by taurine for 2 months, the expression of GFAP was decreased.CONCLUSION: Taurine can down-regulate the expression of GFAP mR-NA and protein, indicating that it can protect retinal pathological change in rats with diabetes mellitus.