Induction of heme oxygenase-1 and major histocompatibility complex antigens in transient forebrain ischemia.
Recent studies strongly suggest that oxidative stresses participate in ischemia/reperfusion-induced neurodegeneration. In addition, heme oxygenase (HO) and major histocompatibility complex (MHC) antigens serve as functional molecules against oxidative stress and as self-recognition markers in the immune system, respectively. In this study, we examined the induction of HO and MHC antigens in the rat hippocampus after transient forebrain ischemia. The protein level of HO-1 was significantly enhanced after an episode of ischemia. After ischemia, HO-1 expression was observed early but transiently in the CA1 pyramidal neurons and later but continuously in glial cells. Glial cells expressing HO-1 were predominantly ameboid microglia, but not astrocytes. Ameboid microglia expressing HO-1 were predominantly localized with MHC class II antigens. These results indicate that (1) HO-1 expression in CA1 pyramidal neurons may be harmful, and (2) ischemia induces HO-1 in ameboid microglia that express MHC class II antigens, indicating a very specific microglial stress protein response.
Department of Neurobiology, Kyoto Pharmaceutical University, Yamashina, Japan.
Y
Y
Matsuoka
Y
Y
Kitamura
M
M
Okazaki
M
M
Sakata
T
T
Tsukahara
T
T
Taniguchi
D000818:Animals; D001253:Astrocytes / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D005786:Gene Expression Regulation; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051547:Heme Oxygenase-1; D006624:Hippocampus / Q000201:enzymology* / Q000276:immunology* / Q000473:pathology; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis; D002546:Ischemic Attack, Transient / Q000201:enzymology* / Q000276:immunology* / Q000473:pathology; D008285:Major Histocompatibility Complex; D008297:Male; D017628:Microglia / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D016548:Prosencephalon / Q000098:blood supply; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000949:Histocompatibility Antigens Class II; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1