Effects of ovariectomy on autophagy and senile plaques in the brain of adult APP/PS1 double transgenic mice

Objective To investigate the effect of ovarian estrogen on autophagy and senile plaques (SP) in the brain of adult APP/PS1 double transgenic mice, and inquire into the mechanism of Alzheimer disease (AD) neuropathogenesis due to estrogen deficiency. Methods APP/PS1 AD mice (3-month old) were divided into ovariectomy group (OVX-AD) and sham group (sham-AD). Two months after operation, transmission electron microscopy (TEM) was employed to observe the morphological structures of the brains of AD model mice, and immunohistochemical staining was performed to examine the changes in SP and autophagy-related proteins LC3 and Beclin-1 in the brain of AD model mice. Results Immunohistochemical staining showed that the number of SP in the brain of OVX-AD mice incrcased significantly compared with that in sham-AD mice, and distribution of SP was observed more extensively, including the cortex and hippocampus. The autophagy related proteins LC3 and Beclin-1 positive neurons were decreased greatly in the OVX-AD mice brain