DNA adducts related to oxidative stress and advanced glycation in diabetic rats.

Author(s)

Fabiana Almeida dos Santos

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2014-10-17

Examining board members

Ana Paula de Melo Loureiro; Fernando Salvador Moreno; Suzana Maria de Souza Vieira

• Advisor: Ana Paula de Melo Loureiro

Abstract

Diabetes mellitus is generally considered one of the most challenging health problems of the 21st century. According to recent estimates from the International Diabetes Federation - IDF, about 382 million people have diabetes and this number is expected to increase beyond 592 million in less than 25 years. For a better understanding of diabetes mellitus and its complications becomes necessary to search for new biomarkers for the disease. The DM promotes oxidative stress, inflammation and the formation of advanced glycation end products (AGEs), which leads to tissue damage in the diabetic patient. Markers of oxidative damage to proteins and lipids in the presence of DM have been widely discussed in literature, however the study of DNA lesions in vivo models still requires more attention. This study aimed to evaluate the oxidative damage and advanced glycation in the kidney, liver, cerebellum, blood and urine of diabetic animals, as well as damage modulation for different periods of insulin treatment in order to verify that the glycaemic control in diabetic animals protects against induction of biomolecules damage. For induction of diabetes in Sprague-Dawley rats were administered 40 mg STZ per kg body weight intravenously. MDA and 5-metildC were evaluated by HPLC-DAD. The quantification of HbA1c and adducts 1,N2-εdGuo, 1,N6-εdAdo, 8-oxodG and CEdG was performed by HPLC-ESI-MS / MS system. The serum nitrite was determined by reading the absorbance in a spectrophotometer and the plasma creatinine concentration was determined by biochemical analyzer. The results showed that metabolic changes triggered by the condition of persistent hyperglycemia are not readily reversed after glycemic control. Blood glucose and HbA1c levels are significantly different between the groups of hyperglycemic and healthy animals, and was observed a fall in HbA1c only from insulin treatment for 6 weeks. In plasma, kidney and liver concentrations follow the profile of MDA concentration of glycated hemoglobin (HbA1c), indicating that the events of glycation and oxidative stress may be related. Glycemic control also showed beneficial effect for urine excretion of CEdG and 1,N6-εdAdo despite could be seen from 8-oxodG levels that the hyperinsulinaemia leads to a frame of oxidative stress. The three lesions are generated by distinct pathways: advanced glycation, lipid peroxidation and ROS. Therefore, beyond glycaemic control, it is important to develop intervention strategies in biochemical pathways altered by the condition of hyperglycemia in order to reduce the complications risk of diabetes mellitus. (AU)

• FAPESP's process: 11/16225-6 - Advanced Glycation products and DNA adducts related to oxidative stress and inflammation in a model of diabetic rats
• Grantee: Fabiana Almeida dos Santos
• Support Opportunities: Scholarships in Brazil - Master