Temporal evolution of neuropathologic changes in an immature rat model of cerebral hypoxia: a light microscopic study.
The sequential evolution of neuropathologic changes was studied in an immature model of cerebral hypoxia-ischemia. According, 7-day postnatal rats were subjected to unilateral common carotid artery ligation combined with 2 h of hypoxia (breathing in 8% oxygen) and their brains were examined by light microscopy at recovery intervals ranging from 0 to 3 weeks. Immediately following hypoxia, a large area with a pale staining border was noted occupying most of the cerebral hemisphere ipsilateral (IL) to the occluded common carotid artery; in approximately half of the brains the dorsomedial cortex of the contralateral (CL) hemisphere was also involved. Most neurons in the pale area had nuclei containing a coarse granular condensation of chromatin. Within a few hours, the majority of neurons in the IL hemisphere had developed pyknotic nuclei and clear or eosinophilic perikarya. After 24 h these changes had evolved in the majority of brains into coagulation necrosis (infarction) in the IL hemisphere and foci of selective neuronal necrosis in the CL cortex. Within a few days infarcts became partially cavitated, and by 3 weeks a smooth-walled cystic infarct had developed. Activated microglia/macrophages and reactive astrocytes were first seen at 4 and 24 h, respectively. No parenchymal neutrophilic infiltrate was seen at any time point.
Towfighi
J
J
Department of Pathology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey 17033, USA.
Zec
N
N
Yager
J
J
Housman
C
C
Vannucci
R C
RC
D000818:Animals; D001253:Astrocytes / Q000502:physiology / Q000648:ultrastructure; D001921:Brain / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology; D002544:Cerebral Infarction / Q000473:pathology; D006098:Granulocytes / Q000502:physiology / Q000648:ultrastructure; D006735:Horseradish Peroxidase; D002534:Hypoxia, Brain / Q000473:pathology*; D017628:Microglia / Q000502:physiology / Q000648:ultrastructure; D009131:Muscle, Smooth, Vascular / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure; D009504:Neutrophils / Q000648:ultrastructure; D016612:Paraffin Embedding; D016613:Plastic Embedding; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D006735:Horseradish Peroxidase