Protection by Taurine and Thiotaurine Against Biochemical and Cellular Alterations Induced by Diabetes in a Rat Model

In this study, the actions of taurine (TAU), a sulfonate, and thiotaurine (TTAU), a thiosulfonate, on diabetes-mediated biochemical alterations in red blood cells (RBCs) and plasma and on the RBC membrane, morphology and spectrin distribution were examined in rats. Diabetes was induced in male Sprague-Dawley rats with streptozotocin (60 mg/kg i.p.) and allowed to progress for 14 days. From days to 56, the rats received a daily, 2.4 mmol/kg, oral dose of TAU or TTAU, 2 mL oral dose of physiological saline or 4 U/kg subcutaneous dose of isophane insulin (INS). Naive rats served as the control group. The rats were sacrificed on day 57 and their blood was collected to measure HbA 1c, to isolate intact RBCs, and to obtain plasma. A 6-weeks treatment with INS effectively lowered the elevations in plasma glucose, cholesterol, triglycerides, and plasma and RBC malondialdehyde and glutathione disulfide while effectively counteracting the decreases in plasma INS, plasma and RBC glutathione redox status, and plasma and RBC activities of antioxidant enzymes caused by diabetes. Also, INS returned the echynocytic appearance and peripheral location of spectrin seen in RBCs from diabetic rats to the normal discocytic shape and uniform distribution. TAU and TTAU were as effective as INS in inhibiting malondialdehyde formation, changes in redox status and oxidative stress in both the plasma and RBC, but were much less effective in controlling hyperglycemia and hypoinsulinemia. Furthermore TTAU was more effective than INS or TAU in lowering the increase in cholesterol to phospholipids ratio in the RBC membrane and, unlike TAU, it was able to normalize the RBC morphology and spectrin distribution.