Autoradiographic Study of Friction Blisters: RNA, DNA, and Protein Synthesis

This study examined synthesis and metabolism of nucleic acids and protein of epidermal cells, as well as cell movement, during blister injury and healing by autoradiography. Tritium-labeled precursors of DNA (tritiated thymidine), RNA (tritiated cytidine), and protein (tritiated histidine and tritiated leucine) were injected intradermally in the palm of human volunteers one hour before or at varying times after friction blister formation. The process of injury continued for about four hours; cells in the base continued to synthesize DNA, but fewer cells synthesized RNA and protein. Granular cells stopped synthesizing new RNA and protein, and failed to differentiate further. Recovery began in the blister base at six hours with increase in: (1) cells synthesizing DNA; (2) production of protein; and (3) speed of cell movement. At 48 hours new keratohyalin granules were formed by protein synthesis taking place in these cells and not due to protein produced in lower layers.