Neuroprotective effect of salidroside against central nervous system inflammation‐induced cognitive deficits: A pivotal role of sirtuin 1‐dependent N rf‐2/ HO ‐1/ NF ‐κ B pathway

Central nervous system (CNS) inflammation occurs in cognitive dysfunctions, but the underlying mechanisms remain unclear. Here, we investigated the role of sirtuin 1 (SIRT1) and salidroside in CNS inflammation‐induced cognitive deficits model. In vivo, CNS inflammation was initiated by a single intracerebroventricular injection of lipopolysaccharide (LPS). The levels of inflammatory cytokines and the capability of free radial scavenging were determined after the LPS challenge. In vivo, salidroside and nicotinamide, a SIRT1 inhibitor, were used in PC12 cell. Of note, with the treatment of salidroside, LPS‐induced learning and memory impairments were effectively improved. Salidroside also remarkably inhibited the inflammatory cytokines, up‐regulated the concentration of superoxide dismutase and inhibited the vitalities of malondialdehyde in serum, hippocampus, and cell supernatant. Besides, the expression of Sirt1, Nrf‐2, HO‐1, Bax, Bcl‐2, caspase‐9, and caspase‐3 and the phosphorylation of AMPK, NF‐κBp65, and IκBα were increased accompanying with the LPS‐induced cognitive impairments, which were significantly suppressed by salidroside treatment. In PC12 cell model, nicotinamide significantly abrogated the beneficial effects of salidroside, as indicated by the antioxidant, anti‐inflammatory, and antiapoptosis signaling. Together, our results showed that salidroside may be a novel therapy drug in neurodegenerative diseases, and the protective effect was involved in SIRT1‐dependent Nrf‐2/HO‐1/NF‐κB pathway.