Kinetics of macrophage subpopulations and expression of monocyte chemoattractant protein-1 (MCP-1) in bleomycin-induced lung injury of rats studied by a novel monoclonal antibody against rat MCP-1.
We investigated the kinetics of macrophage subpopulations and the expression of monocyte chemoattractant protein 1 (MCP-1) in a rat model of bleomycin-induced lung injury. Rat macrophage subpopulations were examined by immunohistochemistry using various anti-rat macrophage monoclonal antibodies (mAbs) and their proliferative capacity by [3H]thymidine (3HTdR) autoradiography. To detect the localization of expressed MCP-1, we generated an mAb against rat MCP-1 for immunohistochemical staining. Expression of MCP-1 messenger RNA (mRNA) was detected by Northern blot hybridization. Shortly after intratracheal instillation of bleomycin, the number of exudate macrophages recognized by mAb TRPM-3 increased in the injured lungs, peaked 3 days later, and decreased thereafter, whereas tissue macrophages identified by mAb ED2 increased slowly and peaked 2 weeks after instillation. Northern blot analysis disclosed that the expression of MCP-1 mRNA in the lung was most prominent 1 day after instillation and declined thereafter, preceding the numerical change of the TRPM-3-positive exudate macrophages. Immunohistochemistry with anti-rat MCP-1 revealed that the main sources of MCP-1 production were alveolar and interstitial macrophages and polymorphonuclear leukocytes. Based on these results, MCP-1 produced by polymorphonuclear leukocytes and by alveolar and interstitial macrophages is thought to induce the infiltration of blood monocytes, and infiltrated exudate macrophages produce MCP-1 to enhance subsequent accumulation of macrophages. In contrast, the expression of MCP-1 did not correlate with the numerical changes of the ED2-positive macrophages.
Sakanashi
Y
Y
Second Department of Pathology, Kumamoto University School of Medicine, Japan.
Takeya
M
M
Yoshimura
T
T
Feng
L
L
Morioka
T
T
Takahashi
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis; D001345:Autoradiography; D001483:Base Sequence; D001761:Bleomycin / Q000633:toxicity*; D015152:Blotting, Northern; D002453:Cell Cycle; D002455:Cell Division; D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D004195:Disease Models, Animal; D005355:Fibrosis; D007150:Immunohistochemistry; D008168:Lung / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D008171:Lung Diseases / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D008264:Macrophages / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D000911:Antibodies, Monoclonal; D018932:Chemokine CCL2; D002630:Chemotactic Factors; D012333:RNA, Messenger; D014316:Tritium; D001761:Bleomycin; D013936:Thymidine