Investigation of the mechanisms involved in the high-dose and long-term acetyl salicylic acid therapy of type I diabetic rats.

Diabetes mellitus has been classified as a conformational disease because of changes induced in the structure and function of proteins due to hyperglycemia. In this study, we investigated the effect of high-dose and long-term use of acetyl salicylic acid (ASA) on the streptozotocin-induced diabetic rats as a model of type I diabetes, with consideration on the structure and/or function of proteins. The N-[methylnitrosocarbamoyl]-d-glucosamine (streptozotocin)-induced diabetic rats together with the normal rats were studied for 5 months with and without receiving 100 mg/kg ASA in drinking water. All rats were investigated from different aspects such as heat shock protein (HSP) 70 level, serum glucose and insulin concentration, advanced glycated end product (AGE) and glycated hemoglobin (HbA1c) formation, lipid profile, high-density lipoprotein (HDL) functionality (paraoxonase1 and lecithin cholesterol acyltransferase activities), and the antioxidant system. In addition, the in vitro effect of ASA on the structure of albumin as a model protein was studied in the presence of glucose by spectroscopic techniques such as fluorometry and circular dichroism. The results show that ASA therapy causes a decrease in the glucose level and AGE and HbA1c formation, improves the lipid profile, HDL functionality, and the antioxidant capacity, induces serum HSP70, and overall decreases mortality of diabetic rats in comparison with the group without treatment. The conformation of glycated bovine serum albumin is different from the native form, and ASA retains the conformation of this protein similar to the native. The improving effect of ASA on diabetic rats is mostly due to its role as a chemopreventive agent in the structural conservation and protection of proteins involved in diabetes pathogenesis.