Chronic cerebral hypoperfusion induces memory deficits and facilitates Aβ generation in C57BL/6J mice

- We developed a new mouse model of CCH by narrowing bilateral common carotid arteries. It is simple to operate in mice.
- Our study found that the destruction of neuronal-glial-vascular units may play a critical role in the pathogenesis of AD.
- This study suggests that if CCH existed before the clinical symptoms of AD, which will promote the further development.
- The intracellular Aβ deposition and neuronal-glial-vascular units provide novel insights in the pathogenesis of AD.
- The model may be used in studies on transgenic mice to provide novel strategies and insights for the intervention of AD.

Alzheimer's disease (AD) is the most common type of dementia frequently responsible for cognitive decline in the elderly. The etiology and molecular mechanism of AD pathogenesis remain inconclusive. Aging and vascular factors are important independent causes and contributors to sporadic AD. Clinical imaging studies showed that cerebral blood flow decreases before cognitive impairment in patients with AD. To investigate the effect of chronic cerebral hypoperfusion (CCH) on cognitive impairment and morphological features, we developed a new manner of CCH mouse model by narrowing bilateral common carotid arteries. Mice started to manifest spatial memory deficits 1 month after the surgery and exhibited behavioral changes in a time-dependent manner. Mice also presented memory deficits accompanied with morphological changes at the neuronal and synaptic levels. CCH damaged the normal neuronal morphology and significantly reduced the expression level of PSD95. CCH activated astrocytes, increased the co-expression of GFAP and AQP4, and destroyed the blood-brain barrier (BBB). Furthermore, CCH facilitated intracellular and extracellular Aβ deposition by up-regulating γ-secretase and β-secretase levels. Our results showed good reproducibility of post-CCH pathological processes, which are characterized by neuronal apoptosis, axonal abnormalities, glial activation, BBB damage, amyloid deposition, and cognitive dysfunction; these processes may be used to decipher the complex interplay and pathological process between CCH and AD. This study provides laboratory evidence for the prevention and treatment of cognitive malfunction and AD.