title: Interleukin (IL)-8 immunoreactivity of injured axons and surrounding oligodendrocytes in traumatic head injury.
abstract: Interleukin (IL)-8 has been suggested to be a positive regulator of myelination in the central nervous system, in addition to its principal role as a chemokine for neutrophils. Immunostaining for beta-amyloid precursor protein (AβPP) is an effective tool for detecting traumatic axonal injury, although AβPP immunoreactivity can also indicate axonal injury due to hypoxic causes. In this study, we examined IL-8 and AβPP immunoreactivity in sections of corpus callosum obtained from deceased patients with blunt head injury and from equivalent control tissue. AβPP immunoreactivity was detected in injured axons, such as axonal bulbs and varicose axons, in 24 of 44 head injury cases. These AβPP immunoreactive cases had survived for more than 3h. The AβPP immunostaining pattern can be classified into two types: traumatic (Pattern 1) and non-traumatic (Pattern 2) axonal injuries, which we described previously [Hayashi et al. Int. J. Legal Med. 129 (2015) 1085-1090]. Three of 44 control cases also showed AβPP immunoreactive injured axons as Pattern 2. In contrast, IL-8 immunoreactivity was detected in 7 AβPP immunoreactive and in 2 non-AβPP immunoreactive head injury cases, but was not detected in any of the 44 control cases, including the 3 AβPP immunoreactive control cases. The IL-8 immunoreactive cases had survived from 3 to 24 days, whereas those cases who survived less than 3 days (n=29) and who survived 90 days (n=1) were not IL-8 immunoreactive. Moreover, IL-8 was detected as Pattern 1 axons only. In addition, double immunofluorescence analysis showed that IL-8 is expressed by oligodendrocytes surrounding injured axons. In conclusion, our results suggest that immunohistochemical detection of IL-8 may be useful as a complementary diagnostic marker of traumatic axonal injury.
authors.affiliation: Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan. Electronic address: takahito@m2.kufm.kagoshima-u.ac.jp.
authors.forename: Takahito
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Ago
authors.affiliation: Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Nakamae
authors.affiliation: Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Higo
authors.affiliation: Department of Legal Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan. Electronic address: ogatam@m.kufm.kagoshima-u.ac.jp.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ogata
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016564:Amyloid beta-Protein Precursor / Q000032:analysis; D001369:Axons / Q000276:immunology / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D003337:Corpus Callosum / Q000276:immunology / Q000378:metabolism; D005260:Female; D049429:Forensic Pathology; D016489:Head Injuries, Closed / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D016209:Interleukin-8 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009836:Oligodendroglia / Q000276:immunology / Q000378:metabolism*; D055815:Young Adult
chemical_list: D016564:Amyloid beta-Protein Precursor; D015415:Biomarkers; C508606:CXCL8 protein, human; D016209:Interleukin-8
keywords: Beta-amyloid precursor protein (AβPP); Immunohistochemistry; Interleukin (IL)-8; Postmortem diagnosis; Remyelination; Traumatic axonal injury