In vivo regulation of rat neutrophil apoptosis occurring spontaneously or induced with TNF-alpha or cycloheximide.
We previously demonstrated that human TNF-alpha induces rapid apoptosis of human neutrophils. To understand better the in vivo significance of neutrophil apoptosis, we examined spontaneous, recombinant human and mouse TNF-alpha- or cycloheximide-induced apoptosis of normal peripheral blood neutrophils (PBN), PBN from rats injected i.p. with proteose peptone or a streptococcus preparation, OK-432 (inflammatory PBN), peritoneally exudated neutrophils (PEN) obtained after a proteose peptone injection, and normal bone marrow neutrophils. The following observations were made. 1) Normal PBN responded to TNF-alpha, but PEN, normal bone marrow neutrophils, and inflammatory PBN at 12 h after stimulation did not. 2) The sensitivity to TNF-alpha of the inflammatory PBN started to decrease at 3 h, was lowest at 12 h, and was almost restored at 52 h after stimulation. 3) Spontaneous apoptosis of normal and inflammatory PBN reached 25% at 12 h after in vitro incubation, but that of PEN and normal bone marrow neutrophils was very low over this period. 4) The sensitivity to cycloheximide (6 h incubation) was high for normal PBN and bone marrow neutrophils, but low for PEN and inflammatory PBN after 12 h. 5) 125I-rhTNF-alpha binding of bone marrow neutrophils was significantly lower than that of normal and inflammatory PBN and PEN. 6) TNF-alpha-induced apoptosis of normal or inflammatory PBN and bone marrow neutrophils was enhanced by treatment with low doses of cycloheximide that alone were barely able to induce neutrophil apoptosis; however, apoptosis of PEN was not. The mechanisms and in vivo significance of these phenomena are discussed.
Tsuchida
H
H
Department of Immunology and Parasitology, Yamagata University School of Medicine, Japan.
Takeda
Y
Y
Takei
H
H
Shinzawa
H
H
Takahashi
T
T
Sendo
F
F
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001854:Bone Marrow Cells; D002364:Caseins / Q000633:toxicity; D003513:Cycloheximide / Q000494:pharmacology*; D006801:Humans; D007249:Inflammation / Q000209:etiology / Q000276:immunology / Q000473:pathology; D008297:Male; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects* / Q000276:immunology; D010446:Peptide Fragments / Q000633:toxicity; D010529:Peritoneal Cavity / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D002364:Caseins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C018135:proteose-peptone; D003513:Cycloheximide