Paeonol increases levels of cortical cytochrome oxidase and vascular actin and improves behavior in a rat model of Alzheimer's disease.

Paeonol(2'-hydroxy-4'-methoxyacetophenone;1-(2-hydroxy-4-methoxyphenyl)ethan-1-one) is a constituent of the bark of the Moutan Cortex (Paeonia suffruticosa). This bark has been used as a traditional Chinese medicine and is reputed to possess a broad range of therapeutic properties probably by virtue of its anti-inflammatory and free radical scavenging properties. The effects of paeonol on a variety of biochemical and behavioral parameters were studied in rat brain in rat brain after experimental animals had been subjected to an intra-hippocampal injection of amyloid peptide, Aβ1-42. Sprague-Dawley rats were randomly divided into groups: saline, sham operated, β-amyloid (Aβ)-injected (intended to model Alzheimer's disease, (AD), and a group receiving both injected amyloid peptide and paeonol. Forty days after intra-hippocampal injection, H&E staining revealed that the lesions in the paeonol-treated group were significantly less than the untreated group. Levels of cytochrome oxidase and α-actin, determined immunohistochemically, were elevated in the paeonol treated group relative to the group receiving amyloid peptide alone. TUNEL staining revealed more apoptotic cells in the walls of the cerebral vascular elements in the AD model group than in the paeonol group. The paeonol-treated group also showed improvement in behavioral indices of learning relative to the group receiving Aβ1-42 alone, as judged using a Y-type electric maze. Treatment with paeonol can protect against many of the alterations resulting from administration of Aβ1-42. in a rat model of AD. These include morphological, biochemical and behavioral changes. Paeonol is a possible therapeutic measure in slowing down the pathogenic processes associated with AD.