An Investigation on the Therapeutic Effect of Thymosin β4 and Its Expression Levels in Streptozotocin-Induced Diabetic Mice.

Thymosin 4 (T4) treatment was known to show the potential therapeutic effects on diabetic complications. This study was performed to determine if T4 expression is changed in both serum and tissues under diabetic conditions and can be a serum biomarker. Type 1 diabetic mice were induced in C57/BL6J mice by intraperitoneal injection of streptozotocin (STZ) at a dose of 50 mg/kg body weight. The mice were sacrificed at 16 weeks after STZ injection. Tissues and plasmas were obtained to determine the expression levels of T4 using ELISA, real time RT-PCR, and immunohistochemistry. The average serum glucose level was increased to approximately 400 mg/dL beginning 2 weeks after the five injections of STZ and lasting for at least 13 weeks until sacrifice. The plasma and tissue levels of T4 in the age-matched control mice were not significantly different from those of the diabetic mice. In conclusion, the T4 expression level in the plasmas and tissues of diabetic mice was not affected by diabetic conditions. It indirectly suggests that the therapeutic effect of T4 on diabetic complications is due to its regenerative effects on damaged tissue but not to the changed expression level of T4 in plasma and tissues of diabetes.