Growth inhibition and morphological changes caused by indomethacin in fibroblasts in vitro.

In a definite range of concentrations indomethacin inhibits the multiplication of fibroblasts in vitro without influencing their viability. The effect of lethal doses of indomethacin on the fine structure of normal and transformed fibroblasts was investigated by light and electron microscopy. The cells grown in flat monolayers became roundish and, varying in sequence, small zeiotic blebs were bulging at the external cell membrane. Beside coarse vesicular transformation of the endoplasmatic reticulum and extension of the perinuclear spaces ballooning of the mitochondria occurred. After breaking up of the vesicles of the endoplasmatic reticulum loosening of the cytoplasmic ground substance associated with enlargement of the hyaline plasma margins was observed in further progress of the experiment. The internal structures of the mitochondria were completely disorganized. In the ultrastructure of the fibroblasts altered by lethal doses of indomethacin no specific sites of drug action could be identified.