Paeonol reduced cerebral infarction involving the superoxide anion and microglia activation in ischemia-reperfusion injured rats.

Both Moutan cortex of Paeonia suffruticosa Andrews (MC) and the root of Paeonia lactiflora Pall (PL) are important Traditional Chinese herbs used commonly to treat inflammatory and pyretic disorders. Paeonol, a common component of MC causes anti-platelet aggregation and scavenges free radicals. Therefore, the aim of the present study is to investigate the effects of Paeonol on cerebral infarct. A total of 60 male Sprague-Dawley (SD) rats were studied. An animal model of cerebral infarct was established by occluding both common carotid arteries and the right middle cerebral artery for 90 min, followed by a 24 h period of reperfusion. The percentage of cerebral infarction area to total brain area in each piece of brain tissue, and neuro-deficit score were measured. Superoxide anion was determined by the number of lucigenin-chemiluminescence (CL) counts. ED1 (mouse anti rat CD68) and interleukin-1beta (IL-1beta) immunostaining in the cerebral infarction region were also investigated for activation of microglia. The results indicated that Paeonol 15 and 20 mg/kg pretreatment and 20 mg posttreatment reduced the cerebral infarction area; Paeonol 15 and 20 mg/kg pretreatment reduced the neuro-deficit score. In addition, Paeonol 20 mg/kg pretreatment reduced the lucigenin-CL counts at 2 h period of reperfusion. The number of ED1 and IL-1beta immunoreactive cells also reduced in the cerebral infarction region; there were no significant changes in blood sugar levels. The results show that Paeonol reduced cerebral infarct and neuro-deficit in rat, suggesting Paeonol might play a similar role in reducing cerebral infarction in humans. Paeonol suppresses and scavenges superoxide anion, and inhibit microglia activation and IL-1beta in ischemia-reperfusion injured rats.