Virgin Coconut Oil-Induced Neuroprotection in Lipopolysaccharide-Challenged Rats is Mediated, in Part, Through Cholinergic, Anti-Oxidative and Anti-Inflammatory Pathways
Nur Syafiqah Rahim, Siong Meng Lim, Vasudevan Mani, Nurul Aqmar Mohamad Nor Hazalin, Abu Bakar Abdul Majeed, Kalavathy Ramasamy
Abstract
Neuroinflammation is associated with neuronal cell death and could lead to chronic neurodegeneration. This study investigated the neuroprotective potential of virgin coconut oil (VCO) against lipopolysaccharide (LPS)-induced cytotoxicity of neuroblastoma SK-N-SH cells. The findings were validated using Wistar rats, which were fed with 1-10 g/kg VCO for 31 days, exposed to LPS (0.25 mg/kg) and subjected to the Morris Water Maze Test. Brain homogenate was subjected to biochemical analyses and gene expression studies. α-Tocopherol (α-T; 150 mg/kg) served as the positive control. VCO (100 µg/mL) significantly (p < 0.01) improved SK-N-SH viability (+57%) and inhibited reactive oxygen species (-31%) in the presence of LPS. VCO (especially 10 g/kg) also significantly (p < 0.05) enhanced spatial memory of LPS-challenged rats. Brain homogenate of VCO-fed rats was presented with increased acetylcholine (+33%) and reduced acetylcholinesterase (-43%). The upregulated antioxidants may have reduced neuroinflammation [malondialdehyde (−51%), nitric oxide (−49%), Cox-2 (−64%) and iNos (−63%)] through upregulation of IL-10 (+30%) and downregulation of IL-1β (-65%) and Interferon-γ (−25%). There was also reduced expression of Bace-1 (-77%). VCO-induced neuroprotection, which was comparable to α-T, could be mediated, in part, through inflammatory, cholinergic and amyloidogenic pathways.