Irradiation effects on wound contraction using a connective tissue model.

To analyze irradiation effects on wound contraction, fibroblasts harvested from human oral mucosa were irradiated (single 2-, 4-, 6-, 8-, and 10-Gy exposures of x-rays). The irradiated fibroblasts were examined for growth ability, and they were cultured three-dimensionally in hydrated collagen gels. The irradiation inhibited growth of fibroblasts and contraction of collagen gels in a dose-dependent manner. In addition, inhibition depended on the duration after exposure. The organization of actin filaments of fibroblasts in this model was examined with fluorescent dye-conjugated phalloidin. Many elongated cell projections were formed in cells of the control group, but the cell projections were almost disrupted in the irradiated cells. X-ray irradiation is thus shown to inhibit wound contraction by affecting the organization of actin filaments in fibroblasts.