Lactobacilli-fermented cow's milk attenuated lipopolysaccharide-induced neuroinflammation and memory impairment in vitro and in vivo

Nutritional interventions are now recommended as strategies to delay Alzheimer's disease (AD) progression. The present study evaluated the neuroprotective effect (anti-inflammation) of lactic acid bacteria (either Lactobacillus fermentum LAB9 or L. casei LABPC) fermented cow's milk (CM) against lipopolysaccharide (LPS)-activated microglial BV2 cells in vitro. The ability of CM-LAB in attenuating memory deficit in LPS-induced mice was also investigated. ICR mice were orally administered with CM-LAB for 28 d before induction of neuroinflammation by LPS. Learning and memory behaviour were assessed using the Morris Water Maze Test. Brain tissues were homogenised for measurement of acetylcholinesterase (AChE), antioxidative, lipid peroxidation (malondialdehyde (MDA)) and nitrosative stress (NO) parameters. Serum was collected for cytokine analysis. CM-LAB9 and CM-LABPC significantly (P < 0·05) decreased NO level but did not affect CD40 expression in vitro. CM-LAB attenuated LPS-induced memory deficit in mice. This was accompanied by significant (P < 0·05) increment of antioxidants (SOD, GSH, GPx) and reduction of MDA, AChE and also pro-inflammatory cytokines. Unfermented cow's milk (UCM) yielded greater cytokine lowering effect than CM-LAB. The present findings suggest that attenuation of LPS-induced neuroinflamation and memory deficit by CM-LAB could be mediated via anti-inflammation through inhibition of AChE and antioxidative activities.