Chronic cerebral hypoperfusion independently exacerbates cognitive impairment within the pathopoiesis of Parkinson's disease via microvascular pathologys.

To date, the role of microvascular pathology and chronic cerebral hypoperfusion (CHH) in the development of mild cognitive impairment in Parkinson's disease (PD-MCI) is unclear. Here, we investigated how the combined injury through interaction of CHH and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity act as an exacerbating element to damagae cognitive fuction in a mouse model. In the present study, C57BL/6 mice underwent MPTP injection. Subjects were classified into a PD with normal cognitive performance (PDCN) group or a PD-MCI group using the Morris Water Maze test. Further, CHH was induced by stenosis of the bilateral common carotid arteries (BCCAs). Consequently, the animals were divided into 7 groups: they are control, sham, BCCAs, PDCN, PD-MCI, PDCN+BCCAs and PD-MCI+BCCAs. The Morris Water Maze test, open field test, histological investigation and western blotting were performed to analyze cerebral microvascular impairment in each group. The results showed that CHH and MPTP injection caused spatial memory and behavioral impairment, accompanied by microvascular impairment and down-regulation of ZO-1 and Occludin at the protein level compared to the control group. The above injuries were synergistically exacerbated in the PDCN+BCCAs group and the PD-MCI+BCCAs group, which paralleled the elevated expression of p-MAPK and p-Akt. In short, our data demonstrate that CHH and MPTP caused cognitive and microvascular impairment separately. Moreover, CHH may exacerbate cognitive impairment in a mouse model of PD. The study provides a new opportunity for understanding the pathogenesis of PD-MCI.