Expression of nucleic acid oxidation metabolites 8-Oxo-GSn and β-amyloid protein in the urine and cerebral tissues of diabetic rats

The aim of the study is to analyze the changes of 8-Oxo GSn expression and to explore the possible mechanism of type 2 diabetes mellitus combined with cognitive disorder using Zucker Diabetic Fatty rats (ZDF). Five-month-old ZDF rats and the wild-type control rats were employed in this study. Immunohistochemical (IHC) staining and isotope dilution high performance liquid chromatography - tandem mass spectrometry (ID - LC - MS/MS) method were used for analyzing 8-Oxo GSn in brain tissues and urine. The biochemical markers (Aβ40 and Aβ42) were also analyzed. In the cerebral cortex and hippocampus of ZDF rats, 8-Oxo GSn level was increased significantly than control rats. Aβ40 and Aβ42 levels were significantly increased in the brain of ZDF rats than control animals (P < 0.05). APP expression level was maximum in ZDF rats than that of control rats (P < 0.05). After eight months of 8-Oxo GSn injection into the brain of ZL rats, Aβ expression was considerably increased in ZL rats than control (P < 0.05). Overexpression of 8-Oxo GSn is one of the main reasons for ZL rats combined cognitive disorder.