The effects of Mycoplasma mobile 163 K on the ciliary epithelium of tracheal organ cultures.

Mycoplasma (M.) mobile 163 K, isolated from the gills of a tench (Tinca tinca L.), was examined for cytotoxic capacities using tracheal organ cultures from gnotobiotic rats and gnotobiotic piglets in pH-controlled experiments (pH 7.2-7.6). The mycoplasmas caused an inhibition of the ciliary activity at incubation temperatures of 20, 25 and 30 degrees C. The strongest cilia stopping effect was observed at an incubation temperature of 25 degrees C, the optimal growth temperature of the mycoplasmas. No ciliostasis occurred at 37 degrees C. The number of the organisms did clearly affect the severity of ciliostasis in the range from 4.0 x 10(4) to 7.7 x 10(8) c.f.u. in rat as well as in porcine tracheal organ cultures. Toxic substances, secreted by the mycoplasmas into the culture medium, could not be detected. In histological investigations cytopathological changes were observed in the epithelial cells, apparent in the destruction and loss of cilia, cytoplasmatic vacuolization, swelling of mitochondria, peripheral orientation of the nuclear chromatin and detachment of epithelial cells from each other and the basal membrane. The final stage of the infection was characterized by complete exfoliation of the epithelial cells and the complete destruction of the multi-layer epithelium. The localization of the mycoplasmas attached to the ciliary epithelium was shown by scanning and transmission electron microscopy.