Multinucleated giant cell appearance after whole body microwave irradiation of rats

Multinucleated giant cells are common for some chronic inflammatory process es in the lung. These cells are formed by fusion of macrophages, but how th e process relates to the kinetics of alveolar macrophage generation is not clear. This study investigated the influence of 2450 MHz microwave irradiat ion on alveolar macrophage kinetics and formation of multinucleated giant c ells after whole body irradiation of rats. The range of electromagnetic rad iation was selected as 2450 MHz microwaves at a power density of 5 - 15 mW/ cm(2). 'A group of experimental animals was divided in four subgroups that received 2, 8, 13 and 22 irradiation treatments of two hours each. The anim als were killed on experimental days 1, 8, 16, and 30. Free lung cell popul ation was obtained by bronchoalveolar lavage. Cell response to the selected irradiation level was followed quantitatively, qualitatively and morpholog ically using standard laboratory methods. Total cell number retrieved by la vage slightly decreased in treated animals showing time and dose-dependence . Cell viability did not significantly change in the irradiated animal grou p (G2) as compared with the control group (GI). Multinucleated cells signif icantly increased (p < 0.01) in treated animals. The elevation of the numbe r of nuclei per cell was time- and dose-dependent. Macrophages with two nuc leoli were more common in animals treated twice or eight times. Polynucleat ion, that is three and more nucleoli in a single cell, was frequently obser ved after 13 or 22 treatments. Binucleation and multinucleation of alveolar macrophages were sensitive time- and dose-dependent morphological indicato rs of pulmonary stress.