title: The importance of infiltrating neutrophils in SDF-1 production leading to regeneration of the thymus after whole-body X-irradiation.
abstract: Our previous study demonstrated that neutrophils transiently infiltrated into a site where apoptosis had been induced. However, the role of infiltrating neutrophils has not been fully elucidated. In this study, we examined their role in regeneration of the thymus after whole-body X-irradiation by focusing on SDF-1 production. After X-irradiation, the thymus became severely atrophied presumably due to phagocytosis of apoptotic thymocytes. At that time, a significant number of neutrophils were detected in the thymus. The thymus was then partially regenerated on day 7, whereas the level of SDF-1 in it was significantly increased on days 3 and 5. Depletion of neutrophils greatly impaired SDF-1 production and the thymus regeneration. Moreover, administration of a CXCR4 antagonist also greatly suppressed the thymus regeneration. Furthermore, coculturing of a stromal cell line with infiltrating neutrophils increased SDF-1 production. These results suggest that infiltrating neutrophils play an auxiliary role in regeneration of the thymus after whole-body X-irradiation through augmentation of SDF-1 production.
authors.affiliation: Division of Molecular Medicine, Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Nakayama
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Shiratsuchi
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kisaburo
authors.initials: K
authors.lastname: Nagata
mesh_terms: D000818:Animals; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000378:metabolism*; D018920:Coculture Techniques; D005434:Flow Cytometry; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D020556:Neutrophil Infiltration / Q000276:immunology / Q000502:physiology*; D009504:Neutrophils / Q000276:immunology*; D009929:Organ Size; D012038:Regeneration; D013950:Thymus Gland / Q000502:physiology* / Q000528:radiation effects; D014916:Whole-Body Irradiation
chemical_list: D054377:Chemokine CXCL12