ACCELERATED REPOPULATION OF INTESTINE POSTIRRADIATION FOLLOWING INTRALUMINAL INJECTION OF A MUCOSAL CELL-SUSPENSION OR ITS SUPERNATANT

The injection of (1-7) x 10(5) mucosal cells into the intestinal lumen at 4 h after 14 or 18 Gy increased the number of intestinal microcolonies (greater-than-or-equal-to 10 cell foci) and microclusters (4-9 cell foci) when assayed at day 3. The effects were less when (a) the interval between irradiation and injection was increased to 20 h, (b) the assay time was increased to 4 days or more, (c) a cell supernatant was injected instead. The data indicate that the injections stimulated earlier regeneration. The effect of the supernatant suggests that the stimulation is mediated through a humoral factor.