A Novel Potent Radical Scavenger, 8-(4-Fluorophenyl)-2-((2E)-3-phenyl-2-propenoyl)-1,2,3,4-tetrahydropyrazolo[5,1-c] [1,2,4]triazine (FR210575), Prevents Neuronal Cell Death in Cultured Primary Neurons and Attenuates Brain Injury after Focal Ischemia in Rats

Abstract

Reactive oxygen species (ROS) play a vital role in brain damage after cerebral ischemia-reperfusion injury, and ROS scavengers have been shown to exert neuroprotective effects against ischemic brain injury. We have recently identified 8-(4-fluorophenyl)-2-((2E)-3-phenyl-2-propenoyl)-1,2,3,4-tetrahydropyrazolo[5,1-c][1,2,4]triazine (FR210575) as a novel, powerful freeradical scavenger. In the present study, the neuroprotective efficacy of FR210575 was evaluated in two neuronal death models in vitro as well as rat focal cerebral ischemia models in vivo. In the first model, primary cortical cultures were exposed to a high oxygen atmosphere (50% O 2 ) for 48 h to induce cell death with apoptotic features. Treatment with FR210575 (10 Ϫ7 -10 Ϫ5 M) significantly inhibited neuronal death. The second model used a growth-factor withdrawal paradigm. Withdrawal of TIP (transferrin, insulin, putrescine and progesterone)-supplemented medium induced apoptotic cell death after 2 days, but treatment with FR210575 exhibited dramatic protection against neuronal death. In two models of cerebral ischemia [photothrombotic occlusion of middle cerebral artery (MCA) for transient model and by permanent MCA occlusion for permanent model], rats received 3-h intravenous infusion (1-10 mg/kg/3 h) of FR210575, with brain damage determined 24 h later. FR210575 (3.2 mg/kg/3 h) significantly reduced the volume of focal damage in the cortex by 36% in the transient model and also reduced the size of ischemic brain damage in the permanent model. These findings indicate that the powerful radical scavenger FR210575 has potent neuroprotective activity and that FR210575 could be an attractive candidate for the treatment of stroke or other neurodegenerative disorders.Oxidative stress is important in neuronal degeneration, including in cerebrovascular injuries such as stroke, neuropathology such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis, as well as in a normal aging (Facchinetti et al., 1998). Reactive oxygen species (ROS) are critical factors for inducing neuronal damage in vitro and in vivo. For example, deprivation of survival factors results in an increase in the cellular levels of ROS (Lieberthal et al., 1998) and subsequent cellular apoptosis, both of which can be blocked by antioxidants or ROS scavengers (Atabay et al., 1996). It has been shown that normal mammalian cells are dependent upon the presence of specific growth factors for maintenance of viability. In the absence of those survival factors, these cells die by apoptosis (Raff, 1992). High-oxygen-induced neuronal death of embryonic neurons is a useful in vitro model of apoptosis (Enokido and Hatanaka, 1993;Ratan et al., 1994). Increases in ROS levels occur in this model, and specific nitric oxide radical scavengers block apoptosis (Satoh et al., 1998;Ishikawa et al., 1999). The brain is particularly susceptible to radical-mediated neuronal damage because of high levels of oxygen consumption unsaturated fatty acids and iron stores, combined with...

Pathophysiology, treatment, and animal and cellular models of human ischemic stroke

“…Administration of uric acid resulted in a large and significant reduction in ischemic damage and improved behavioral outcome [146]. Edaravone, tetramethylpyrazine, alpha-phenyl-N-tert-butyl-nitrone, FR210575 and NXY-59 are some of other free radical inhibitors that have been shown to be effective against experimental stroke injury [147,148]. Completed clinical trials with free radical scavengers, however, have had limited success after acute ischemic stroke.…”

The Potential of Tetrandrine as a Protective Agent for Ischemic Stroke

“…Because ROS are involved in stroke-induced brain injury, thus, agents either blocking ROS production or inhibiting their activation are considered beneficial for the prevention or treatment of stroke. Although various antioxidants have been shown to be effective against experimental stroke injury [ 54 , 55 ]; clinically they have only limited success for the treatment of acute ischemic stroke [ 56 , 57 ].…”

Brain Poster Session: Neuroprotection

“…Many synthetic anti-oxidants have shown neuroprotective effect in ischemia and reperfusion-induced cerebral injury. 6,7 Naturally occurring plant contents such as phenolic compounds, carotenoids, ascorbic acid, thiols, and tocopherols have also shown anti-oxidant activity. 8,9 Objective: The present study has been designed to investigate the neuroprotective effect of extracts of two plants possessing antioxidant activity viz Allium cepa and Ocimum basilicum on Ischemia and Reperfusion induced cerebral ischemia in Swiss albino mice.…”