Neuroprotective efficacy and mechanisms of novel pyrrolopyrimidine lipid peroxidation inhibitors in the gerbil forebrain ischemia model.
A brief period of bilateral carotid occlusion (BCO)-induced forebrain ischemia in gerbils triggers neuronal degeneration and the subsequent expression of amyloid precursor protein (APP), b-amyloid protein (b-AP), and apolipoprotein E (APO-E) in the selectively vulnerable CA1 region of the hippocampus. The increase in immunoreactivity is secondary to the postischemic degeneration of the CA1 neurons and is largely astrocyte-derived as evidenced by a simultaneous increase in glial fibrillary acidic protein (GFAP) staining. Oxygen radical-induced lipid peroxidation has been strongly suggested to play a role in postischemic neuronal damage and Alzheimer's disease. Recent literature suggests a possible link between early oxidative stress and APP overexpression. Therefore, the present investigation examined the effect of two novel brain-penetrating pyrrolopyrimidine lipid peroxidation inhibitors (PNU-101033E and PNU-104067F) on CA1 neurodegeneration and the subsequent increase in APP, b-AP, APO-E, and GFAP immunostaining at 4 days after a 5-minute episode of forebrain ischemia. Using an antibody for lipid peroxidation-derived malondialdehyde (MDA)-modified proteins, the authors also examined the effects of PNU-104067F on MDA immunostaining 2 days after ischemia, before completion of the neuronal loss. At 2 days, the authors also evaluated microglial activation using an antibody to surface major histocompatibility complex class II antigen expressed by activated microglia. Gerbils were treated at 30 mg/kg orally 30 minutes before the BCO and 2 hours after ischemia, followed by daily dosing for the next day (microglia and MDA) and the successive 3 days for APP, b-AP, APO-E, and GFAP immunostaining. APP and APO-E staining was significantly suppressed by 50% and 66%, respectively, with either compound. b-AP immunoreactivity was decreased 56% with both compounds, and GFAP expression was significantly decreased 53% (PNU-101033E) and 60.5% (PNU-104067F). There was a concomitant partial sparing of the CA1 hippocampal neurons by both PNU-101033E and PNU-104067F (P < .01) as determined by cresyl violet histochemistry. PNU-104067F significantly inhibited lipid peroxidation-derived MDA immunostaining and microglia activation (P < .05) at 48 hours after ischemia. Brain-penetrable lipid peroxidation inhibitors may provide attenuation of various glial response proteins after ischemic injury, probably secondary to neuronal protection.
Oostveen
J A
JA
Central Nervous System Diseases Research, Pharmacia & Upjohn, Inc., Kalamazoo, Michigan, USA.
Dunn
E
E
Carter
D B
DB
Hall
E D
ED
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism* / Q000517:prevention & control*; D016923:Cell Death / Q000187:drug effects; D005849:Gerbillinae; D007150:Immunohistochemistry; D050356:Lipid Metabolism; D015227:Lipid Peroxidation / Q000187:drug effects*; D008297:Male; D016548:Prosencephalon / Q000098:blood supply* / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology*
C112281:PNU 101033E; C112280:PNU 104067F; D011743:Pyrimidines; D011758:Pyrroles