Morphological aspects in phase-contrast and transmission electron microscopy of senescent cultures of bovine aortic endothelial cells.
Some cultures of bovine aortic endothelial cells underwent an early senescence process, which may have been favoured by a special differential attachment trypsinization procedure. In order to better characterize this phenomenon, the cultures were observed at phase-contrast and electron microscopy at various passages. In phase-contrast microscopy, senescent cells were always larger than "younger" cells, and giant cells were very frequent. A great heterogeneity both of shape and size was present and the cells appeared shrunken, rigid and unable to cover the whole surface of the flask. In many senescent cells long fibres, running from one to the other side of the cytoplasm and often bridging over the nucleus were found. At transmission electron microscopy, together with a great abundance of rough endoplasmic reticulum, mitochondria and lysosomes, and the occasional presence of Weibel-Palade bodies, peripheric bundles of filaments, probably referable to actin or acto-myosin were found. These fibres may be interpreted as "stress fibres" and, as they are expression of a tension not accompanied by an effective cell motility, it seems of interest that they appear in senescent cells, which are often unable to cover the whole surface of flasks by migrating and subsequently proliferating in empty areas.
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology*; D002417:Cattle; D002470:Cell Survival; D004727:Endothelium / Q000648:ultrastructure*; D008854:Microscopy, Electron