Background Alzheimer's disease (AD) is the core cause of dementia in elderly populations.
One of the main hallmarks of AD is extracellular amyloid beta (A beta) accumulation
(APP-pathology) associated with glial-mediated neuroinflammation. Whole-Body Vibration
(WBV) is a passive form of exercise, but its effects on AD pathology are still unknown.
Methods Five months old male J20 mice (n = 26) and their wild type (WT) littermates
(n = 24) were used to investigate the effect of WBV on amyloid pathology and the healthy
brain. Both J20 and WT mice underwent WBV on a vibration platform or pseudo vibration
treatment. The vibration intervention consisted of 2 WBV sessions of 10 min per day,
five days per week for five consecutive weeks. After five weeks of WBV, the balance
beam test was used to assess motor performance. Brain tissue was collected to quantify
A beta deposition and immunomarkers of astrocytes and microglia. Results J20 mice
have a limited number of plaques at this relatively young age. Amyloid plaque load
was not affected by WBV. Microglia activation based on IBA1-immunostaining was significantly
increased in the J20 animals compared to the WT littermates, whereas CD68 expression
was not significantly altered. WBV treatment was effective to ameliorate microglia
activation based on morphology in both J20 and WT animals in the Dentate Gyrus, but
not so in the other subregions. Furthermore, GFAP expression based on coverage was
reduced in J20 pseudo-treated mice compared to the WT littermates and it was significantly
reserved in the J20 WBV vs. pseudo-treated animals. Further, only for the WT animals
a tendency of improved motor performance was observed in the WBV group compared to
the pseudo vibration group. Conclusion In accordance with the literature, we detected
an early plaque load, reduced GFAP expression and increased microglia activity in
J20 mice at the age of similar to 6 months. Our findings indicate that WBV has beneficial
effects on the early progression of brain pathology. WBV restored, above all, the
morphology of GFAP positive astrocytes to the WT level that could be considered the
non-pathological and hence "healthy" level. Next experiments need to be performed
to determine whether WBV is also affective in J20 mice of older age or other AD mouse
models.
