Magnetometric estimation of organelle motion in hamster lung macrophages in vitro: the effects of temperature.
Pulmonary macrophages, containing ingested ferrimagnetic particles, were studied in vitro. Magnetic particles (Fe3O4) suspended in saline were repeatedly instilled intratracheally into the lungs of Syrian golden hamsters. Later the animals were sacrificed and pulmonary macrophages were harvested by repeated lung lavage. After monolayer cultures were established, the particles previously phagocytized by the macrophages were magnetized and aligned by applying an external field. After the external field was removed, the particles produced a remanent magnetic field which gradually decreased due to random misalignment of the particles (relaxation). When relaxation was measured at various incubation temperatures, we found that relaxation slowed as the temperature decreased; we believe that this reflects decreased organelle motion. These results provide direct evidence that relaxation measured previously in intact animals is related to intracellular movements. Magnetometry can be used to quantitate the motion of cell organelles and thus the influence of altered cytoplasmic rheology and cytoskeletal activity.
Nemoto
I
I
Tokyo Denki University, School of Science and Engineering, Saitama, Japan.
Toyotama
H
H
Brain
J D
JD
Gehr
P
P
D000818:Animals; D002478:Cells, Cultured; D006224:Cricetinae; D008168:Lung; D008264:Macrophages / Q000502:physiology*; D008280:Magnetics; D008647:Mesocricetus; D015388:Organelles / Q000502:physiology*; D013696:Temperature