Transient induction of heme oxygenase after cortical stab wound injury.
Heme oxygenase (HO) exists as two isoenzymes designated heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2). HO-1 has been identified as a heat shock or stress protein and is inducible whereas HO-2 is largely refractory to induction. HO-2 is the predominant isoenzyme in normal brain and appears to have a predominantly neuronal distribution in cerebral cortex. Cortical stab wound injury resulted in HO-1 induction as determined by Western blot analysis. Immunohistochemical analysis suggested that induced HO-1 was largely restricted to reactive astrocytes and macrophage-like cells. Enhanced HO-1 immunoreactivity was observed in hypertrophied, GFAP+ reactive astrocytes near the wound margin as early as 12 h after injury. Very rarely were HO-1+ neurons observed and then only up to 6 h after stabbing. Maximal numbers of HO-1+ astrocytes were found 3 days after stabbing. Their numbers declined thereafter. By 5 days after stab injury few HO-1+ reactive astrocytes were observed although GFAP+ reactive astrocytes were still prominent near the wound margin. HO-1+ macrophage-like cells were initially observed between 1 and 3 days after injury and they persisted in the margin of the wound for at least 14 days. The proximity of HO-1+ cells to the wound margin suggests that factors associated with injury contribute to the regulation of HO-1 in injured cortex.
Dwyer
B E
BE
Molecular Neurobiology Laboratory, Department of Veterans Affairs Medical Center, Sepulveda, CA 91343, USA.
Nishimura
R N
RN
Lu
S Y
SY
Alcaraz
A
A
D000818:Animals; D001253:Astrocytes / Q000201:enzymology; D002540:Cerebral Cortex / Q000293:injuries*; D004790:Enzyme Induction; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D007527:Isoenzymes / Q000096:biosynthesis*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D014951:Wounds, Stab
D007527:Isoenzymes; D006419:Heme Oxygenase (Decyclizing)