Aloin attenuates cognitive impairment and inflammation induced by d-galactose via down-regulating ERK, p38 and NF-κB signaling pathway.

Oxidative stress is considered as major culprit for neurodegenerative diseases and triggers cognitive and memory impairments. The present study mainly aimed to study the protective effects and underlying mechanisms of aloin on d-galactose (d-gal) induced ageing mice. Our results demonstrated that chronic administration of d-gal (150 mg kg) in mice caused spontaneous and cognitive impairments, as determined by open-field test and Morris water-maze test. Aloin treatment significantly ameliorated histopathological damage, attenuated the microglia activation and reduced levels of inflammatory mediators, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in the hippocampus. Moreover, it effectively suppressed the level of reactive oxygen species (ROS) and increased antioxidant enzymes activities. Further data showed that these protective effects were accompanied by inhibition of the activation of nuclear factor kappa B and the phosphorylation of p38 and ERK. In conclusion, the present study suggests that aloin can ameliorate d-gal induced oxidative stress, cognitive impairment and inflammation, possibly via mediating the ERK, p38 and NF-κB signaling pathways.