ADAPTIVE RESPONSES OF PULMONARY MACROPHAGIC SYSTEM TO CARBON .2. MORPHOLOGIC STUDIES

  • 1 January 1978
    • journal article
    • research article
    • Vol. 38  (4) , 430-438
Abstract
The increased output of alveolar macrophages in response to a heavy load of particulate material is well known but the relationship of this cellular outpouring to the precise location of the particles is not clear. An overload situation was utilized in which 4 mg of C were instilled into the lungs of mice; the sequential cellular events were correlated with the patterns of C transport over a 28-day period using light microscopy and EM. At 12 hours some free C crossed the type 1 cells to reach the interstitium; later it was observed in peribronchial and perivascular interstitial cells. In the alveoli, free macrophages were loaded with C but passage of these cells from airways to interstitium was never observed. The early increase in macrophagic output was related to monocytic migration from small pulmonary vessels. This initial cellular efflux may be a nonspecific inflammatory response that is possibly due to release of a chemotactic factor by the interaction of C with the type 1 cells. Maintenance of the large number of free macrophages appeared to be related to increased mitotic activity of the interstitial macrophagic population. The proliferative burst of these cells may be triggered by the arrival of free particles in the interstitium.

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