Neutrophil involvement in the retention and clearance of dust intratracheally instilled into the lungs of F344/N rats.
This study evaluated polymorphonuclear leukocyte (PMN) involvement in translocation of dust to bronchial lymph nodes after deposition of dust in the lungs of control and neutropenic F344/N rats. Rats were rendered neutropenic with an intraperitoneal (IP) injection of anti-rat PMN antiserum (APA); control rats were injected IP with 0.9% saline solution. Eighteen hours after IP injections, control and APA-treated rats were instilled intratracheally with 5 x 10(8) microspheres suspended in 0.9% saline solution, which caused an influx of PMNs into the pulmonary airspaces of control rats, but not of APA-treated rats. One day postinstillation (PI), 77.2% of the microspheres recovered in bronchoalveolar lavage fluid (BALF) from control rats were associated with pulmonary alveolar macrophages (PAMs) and 18.8% with PMNs; 4.0% were free. In BALF from the APA-treated rats, 66.3% of the microspheres were associated with PAMs and 0.3% with PMNs; 36.3% were free. Two days PI, about 95% of the microspheres in BALF from control and APA-treated rats were associated with PAMs; by 4 and 7 days PI, essentially 100% were with PAMs. Amounts of microspheres translocated to bronchial lymph nodes of control rats were four fold less than in the APA-treated rats on days 2, 4, and 7 PI (p < .05). The results suggest that PMNs in pulmonary airspaces of F344/N rats phagocytize dust and thereby interfere with the mechanism(s) involved in dust penetration into the pulmonary interstitium.
Snipes
M B
MB
Inhalation Toxicology Research Institute, Albuquerque, New Mexico 87185, USA.
Harkema
J R
JR
Hotchkiss
J A
JA
Bice
D E
DE
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D004391:Dust; D004906:Erythrocyte Count / Q000187:drug effects; D007106:Immune Sera / Q000097:blood / Q000494:pharmacology; D007958:Leukocyte Count / Q000187:drug effects; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008198:Lymph Nodes / Q000378:metabolism; D008297:Male; D008863:Microspheres; D009503:Neutropenia / Q000139:chemically induced / Q000378:metabolism*; D009504:Neutrophils / Q000378:metabolism*; D011137:Polystyrenes / Q000493:pharmacokinetics; D051381:Rats; D011916:Rats, Inbred F344
D004391:Dust; D007106:Immune Sera; D011137:Polystyrenes; C024075:styrofoam