Improved effect of APP17 peptide on overexpression of phosphorylated Tau protein in brain tissues of mice with diabetes mellitus

Pengwen WANG; Shan LU; Yaping LEI; Zhiwei ZHAO; Zhijuan JI; Shuli SHENG

ABSTRACT

BACKGROUND:

Overexpression of phosphorylated Tau protein is a factor of dementia, and scholars abroad find that APP17 peptide may have effect on it.

OBJECTIVE:

To observe changes of phosphorylated Tau protein Ser202/Thr205 of mice with diabetes mellitus (DM) after injection of APP17 peptide.

DESIGN:

Randomized control study.

SETTING:

Department of Pathology, Capital University of Medical Sciences; Department of Brain Aging, Xuanwu Hospital, Capital University of Medical Sciences.MATERIALS The experiment was carried out in the Pathological Department of Capital University of Medical Sciences and Brain Aging Department of Beijing Xuanwu Hospital. A total of 18 male Kunming mice of 8 weeks old and weighing 28-32 g were randomly divided into control group, DM group and APP17 peptide group with 6 in each group.

METHODS:

DM models were induced by streptozotocin (STZ) through selectively destroying β-islet cells; meanwhile, APP17 peptide was intraperitoneally injected into mice. Four weeks later, brain tissue underwentimmunohistochemical staining with AT-8 (Ser202/Thr205, a special monoclonal antibody).MAIN OUTCOME

MEASURES:

① Morphological observation; ② AT-8 distribution; ③ quantitative analysis of immunohistochemical staining.

RESULTS:

Positive AT-8 cells in DM group were distributed in retrosplenial cortex, hippocampus, thalamus, hypothalamus, etc.; however, those incontrol and APP17 peptide groups were only distributed in retrosplenial cortex and hippocampus, and poorly stained.

CONCLUSION:

Positive AT-8 cells may be widely distributed in neurons of brains of DM mice; however, APP17 peptide may normalize the expression of positive AT-8 cells.