Acetyl-L-carnitine confers neuroprotection against lipopolysaccharide (LPS) -induced neuroinflammation by targeting TLR4/NFκB, autophagy, inflammation and oxidative stress

Acetyl-L-carnitine has been shown to exert neuroprotection against neurodegenerative diseases. The present study was performed to evaluate neuroprotection effects of acetyl-L-carnitine against lipopolysaccharide (LPS) -induced neuroinflammation and clarify possible mechanisms. A single dose (500 µg/kg) of LPS was intraperitoneally injected to rats to induce model. The animals were intraperitoneally treated with different doses of acetyl-L-carnitine (30, 60, and 100) for 6 days. Y-maze task, single-trial passive avoidance and novel object recognition tests were used to evaluate memory impairments. ELISA assay was used to evaluate the expression of TLR4/NFκB, autophagic and oxidative stress markers. Our result showed that intraperitoneal injection of LPS resulted in initiation of neuroinflammation by activation of TLR4/NFκB, suppression of autophagic markers such as LC3 II/ LC3 I ratio and becline-1, and excessive production of ROS and MDA. Intraperitoneal administration of acetyl-L-carnitine contributed to neuroprotection against LPS -induced neuroinflammation by suppression of TLR4/NFκB pathway, restoring activity of autophagy and inhibition of oxidative stress. Collectively, our findings show that acetyl-L-carnitine attenuated LPS-induced neuroinflammation by targeting TLR4/NFκB pathway, autophagy and oxidative stress.