[Antioxidative defense and structural changes in the brain of rats with experimental diabetes mellitus]

The state of enzymatic and non-enzymatic components of the antioxidative defense system (ADS) and lipid peroxidation was studied in the homogenates of the brain of rats with diabetes melhtus (DM) on days 30, 60, and 90 after administration of alloxan. There was a decrease in the buffer capacity of ADS: reductions in the activities of superoxide dismutase (on DM days 60 and 90), glutathione peroxidase and antiradical activity (on day 90) and glutathione reductase (in all periods of DM). This was followed by the progressive enhancement of lipid peroxidation processes, achieving the maximum magnitude on day 90 of DM (as estimated by the level of malonic dialdehyde). Concurrent brain tissue ultrastructural analysis revealed slightly pronounced oxidative lesions of all cell elements, which enhanced by day 90 of DM. The most marked changes were found in the neuroglial cells, in astrocytes in particular, as compared with cerebral microvascular neurons and endotheliocytes. Administration of the a-lipoic acid agent espa-lipon to rats with DM produced a significant positive effect on the state of the ADS components, promoted the elimination of active manifestations of abnormal processes in the neuroglial cells and neurons and the development of compensatory and reducing processes.