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.
Department of Pathology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey 17033, USA.
J
J
Towfighi
N
N
Zec
J
J
Yager
C
C
Housman
R C
RC
Vannucci
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