| The diabetic rats model was established by using intraperitoneal injection of streptozotocin(STZ) rapidly, to evaluate the expression of autophagy related factors LC3, Bnip-3 and apoptosis related factors Bcl-2and Bax in brain damage of experimental diabetic rats,the pathological changes,and the ultrastructure of brain cells. So as to clarify the role of autophagy related factor LC3, Bnip-3 and apoptosis related factor Bcl-2and Bax in diabetic brain injury and their relationships.After adaptive feeding a week, 40 male SD rats aged 8 weeks were randomly divided into two groups which were known as diabetic group and control group. Each group had 20 rats. Diabetes group were injected1% streptozotocin(60mg / kg) and the control group were injected citrate buffer. The rats were sacrificed after 12 weeks feeding and the brain tissue was obtained. We used HE staining to observe pathological changes and used three-steps immunohistochemical method to detect the expression of LC3, Bnip-3, Bcl-2 and Bax in the cerebral cortex of the rats. The ultra-structure of cerebral cortex cells were observed by transmission electron microscope(TEM).The expression of LC3, Bnip-3, Bcl-2 and Bax in rat cerebral cortex was detected by western blot method.Compared with the control group,The diabetic rats brain pathology showed that cells arranged more disordered, distributed more unevenly,cell bodies were smaller, cytoplasm stained lighter red, and the number of nerve cells of normal morphology was less. Positive number of LC3,Bnip-3 and Bax in brain tissue of diabetic rats was significantly higher than that in the control group, and the difference was statistically significant(P<0.05); positive number of Bcl-2 was significantly lowerthan that in the control group, and the difference was statistically significant(P<0.05).In diabetic rats, LC3 and Bnip-3 showed a weak positive correlation(P <0.05), and Bcl-2 and Bax irrelevant; Bnip-3 and Bax was positively weak correlation(P <0.05), and Bcl-2 was no correlation; Bcl-2 and Bax irrelevant.Compared with the control group,the ultrastructure of the transmission electron microscope showed that the perinuclear space was wider; the nuclear chromatin was highly condensed, the volume of it decreased, its electron concentration increased, it was on the boundary of the karyotheca,and its thickness was nonuniform. Cytoplasm was also highly concentrated, the volume of it was reduced, and the cellular matrix electron density was increased.There was the a typical formation of double-membrane autophagosome in the cell.The western blot method showed that there was the relatively high expression of LC3, Bnip-3 and Bax, and the relatively low expression of Bcl-2 in the diabetes group. All that indicate that autophagy factors and apoptotic factors involves in the process of brain injury in diabetic rat,which may be one of the mechanisms of diabetic brain injury. |
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