The cellular glutathione (GSH) content of two- and three-dimensional cell cultures of V79 hamster lung cells has been studied. As previously described, cells in monolayer cultures show a decrease in GSH when they reach the confluent state. Three-dimensional cell cultures (multicell spheroids) allow a smoother transition from the initial proliferating to the nonproliferating status, and they show a central area of necrosis when a certain diameter is reached. Cellular GSH content in spheroids is variable throughout the culturing period: 1) GSH content (expressed per mg protein) is lower in spheroids with central necrotic areas than in smaller spheroids without necrosis, and 2) results expressed per cell number show a sharp increase around the diameter where necrosis appears. Once a relatively large necrotic area has been established, GSH decreases again to approximately the prenecrotic level. Interestingly, this GSH "peak" is not dependent on the time in culture but on the spheroid size. Acute hypoxia occurs in central areas of spheroids at a much higher size range than those described herein. Thus we suggest a combination of factors, which may include oxidative stress among others, as the explanation for these cellular GSH variations.
In vitro three-dimensional cell cultures for bone sarcomas
