Neuroprotective effects of nerolidol against Alzheimer's disease in Wistar rats

Alzheimer's disease (AD) is the most common type of cognitive disorder in an elderly population associated with the accumulation of amyloid plaques and neurofibrillary tangles. Nerolidol is assumed to have neuroprotection effects. This study aimed to investigate the therapeutic effects of nerolidol on the Aβ-induced model of AD in rats. Hippocampal injection of Aβ was used to induce AD. Animals were randomly divided into control, sham (received PBS as Aβ solvent), AD, DNPZ (AD + donepezil, 4 weeks); NRD-50 (AD + nerolidol, 50 mg/kg, 4 weeks), NRD-100 (AD + nerolidol, 100 mg/kg, 4 weeks; Prot (rats which received 100 mg/kg nerolidol for two weeks before Aβ administration), and Solv (AD + sunflower oil as nerolidol solvent, 4 weeks) groups. All rats were subjected to a memory behavioral passive avoidance test by shuttle box. Thioflavin-S staining was performed to confirm Aβ plaque formation and measured using ImageJ analyzing program. BDNF and CREB-1 expressions were analyzed by immunohistochemistry assay. Aβ induced AD by Aβ plaques formation and increasing step-through latency time. It reduced the expression of BDNF and CREB-1 protein. Administration of nerolidol or donepezil improved these features by decreasing Aβ and increasing BDNF and CREB-1 expression and latency time. Nerolidol is likely to provide protection against AD. It may prevent dementia through the mediation of BDNF-CREB-1 expression and cholinergic nerve cells restoring. It seems that the administration of nerolidol before the onset of the disease will be more effective than after.