Studies on hypoxia V. Effects of anoxia on developing connective tissue cells in rats

The effect of anoxia on protein synthesis of developing connective tissue cells was studied by radioautography. Neonatal rats were subjected to anoxia for 20 minutes and were immediately injected with 3 μc/gm body weight of leucine‐H 3 intraperitoneally. They were sacrificed at different intervals after injection. Control animals were handled identically, except that atmospheric air was made available. The heads of the animals were prepared for radioautography in the standard manner. The number of grains was counted over individual fibrobalsts, osteoblasts and chondrocytes of histologically comparable regions, and the data were statistically evaluated. The number of grains per cell was significantly lower in experimental animals sacrificed at one hour after the anoxic treatment and leucine‐H 3 administration. At this time, the average grain number per cell in the experimental animal was less than 50% of the control. The difference was about 20% by four hours and was negligible after 24 hours. The result is interpreted to indicate that the overall protein synthesis in connective tissues is immediately but temporarily suppressed by anoxia and that such suppression might lead to a later functional disturbance among these cells.