Transient infiltration of neutrophils into the thymus in association with apoptosis induced by whole-body X-irradiation.
Generally, the process of apoptosis does not cause leakage of noxious cytosolic contents and is therefore non-inflammatory. However, as previously shown, macrophages ingesting apoptotic CTLL-2 cells produced pro-inflammatory cytokines, particularly interleukin-8 (IL-8) and macrophage inflammatory protein-2 (MIP-2), a murine IL-8 homolog. This predicted that rapid and massive apoptosis may induce neutrophil accumulation in vivo. In this study, we tested this prediction by inducing apoptosis by whole-body X-irradiation in mice. After exposure to 4 Gy X-ray irradiation, mice exhibited considerable apoptosis of thymic cells, which was associated with transient infiltration of neutrophils as well as MIP-2 mRNA expression. In contrast, in p53-deficient mice in which irradiation-induced apoptosis was suppressed, as has been reported, infiltration of neutrophils into the thymus was less than that found in p53+/+ mice. Taken together, these results suggest that massive and rapid apoptosis can result in infiltration of neutrophils.
Uchimura
E
E
Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Japan.
Watanabe
N
N
Niwa
O
O
Muto
M
M
Kobayashi
Y
Y
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D054426:Chemokine CXCL2; D005260:Female; D008264:Macrophages / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015846:Monokines / Q000235:genetics / Q000276:immunology; D020556:Neutrophil Infiltration / Q000276:immunology / Q000528:radiation effects*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000528:radiation effects*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000276:immunology; D014916:Whole-Body Irradiation
D054426:Chemokine CXCL2; D015846:Monokines; D016159:Tumor Suppressor Protein p53