title: Apoptosis and microglial activation in influenza encephalopathy.
abstract: During influenza epidemics in Japan, the number of children with acute encephalopathies and encephalitis has recently increased. Although the pathophysiologies remain unclear, there is usually brain edema with evidence of damage to the blood-brain-barrier (BBB). We investigated the glial reaction and apoptosis in brains of eight such cases comprising two of acute necrotizing encephalopathy and six of influenza encephalopathy, and compared the results with those in five control brains. Apoptosis, evidenced by chromatin condensation and fragmentation in hematoxylin sections, in situ end labeling of fragmented DNA (TUNEL) and DNA laddering, was observed in neurons and glial cells in four brains with influenza encephalopathy. In the TUNEL-positive brains, the increase in microglia was greater than in the TUNEL-negative brains. Immunoreactivity for active-caspase 3, demonstrated by immunohistochemistry, and the overexpression of a caspase-cleaved fragment of poly(ADP-ribose) polymerase, demonstrated by Western blotting, indicated that activation of caspase 3 is involved in the apoptotic pathway in the brains of influenza encephalopathy cases. Apoptosis or specific pathological processes that cause apoptosis may give rise to aggravated encephalopathy.
authors.affiliation: Department of Mental Retardation and Birth Defect Research, National Institute of Neuroscience, NCNP, Tokyo, Japan. ysuzuki@med.nagoya-u.ac.jp
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nakai
authors.forename: Masayuki
authors.initials: M
authors.lastname: Itoh
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizuguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ozawa
authors.forename: Etsuo
authors.initials: E
authors.lastname: Okazaki
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Takahashi
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Ohtani
authors.forename: Akira
authors.initials: A
authors.lastname: Ogawa
authors.forename: Michihiko
authors.initials: M
authors.lastname: Narita
authors.forename: Takehiro
authors.initials: T
authors.lastname: Togashi
authors.forename: Sachio
authors.initials: S
authors.lastname: Takashima
mesh_terms: D000293:Adolescent; D017209:Apoptosis; D015153:Blotting, Western; D001927:Brain Diseases / Q000209:etiology* / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D020805:Central Nervous System Viral Diseases / Q000150:complications* / Q000473:pathology; D002675:Child, Preschool; D004660:Encephalitis / Q000209:etiology / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007223:Infant; D008297:Male; D017628:Microglia / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D009975:Orthomyxoviridae
chemical_list: C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases