Comparison Between Flurbiprofen and Its Nitric Oxide-releasing Derivatives HCT-1026 and NCX-2216 on Abeta(1-42)-induced Brain Inflammation and Neuronal Damage in the Rat

Brain inflammation is an underlying factor in the pathogenesis of Alzheimers disease (AD). We investigated, in vivo, whether differences exist in the anti-inflammatory and neuroprotective actions of flurbiprofen and its two nitric oxide-donor derivatives, HCT-1026 and NCX-2216, and the ability of these two derivatives to release nitric oxide in the brain. In adult rats injected into the nucleus basalis with preaggregated Abeta(1-42) we investigated glia reaction, the induction of inducible nitric oxide synthase (iNOS), the activation of p38 mitogen-activated protein kinase (p38MAPK) pathway and the number of choline acetyltransferase (ChAT)-positive neurons and, in naive rats we investigated, by microdialysis, cortical extracellular levels of nitrite. Injection of Abeta(1-42) induced iNOS and activation of p38MAPK 7 days after injection and an intense microglia and astrocyte reaction along with a marked reduction in the number ChAT-positive neurons, persisting up to at least 21 days. Flurbiprofen, HCT-1026 and NCX-2216 (15 mg/kg) significantly attenuated the Abeta(1-42)-induced glia reaction, iNOS induction and p38MAPK activation 7 days after treatment and astrocytes reaction 21 days after treatment. On an equimolar basis, HCT-1026 resulted the most active agent in reducing the Abeta(1-42)-induced microglia reaction. The cholinergic cell loss was also significantly reduced by 21 days of HCT-1026 treatment. No differences in body weight were found between the animals treated for 21 days with 15 mg/kg of either HCT-1026 or NCX-2216 and the controls. Oral administration of HCT-1026 (15 mg/kg) or NCX-2216 (100 mg/kg) to naive rats was followed by significant and long lasting increases in cortical nitrite levels. These findings indicate that the addition of a nitric oxide donor potentiates the anti-inflammatory activity of flurbiprofen in a model of brain inflammation.