Changes Bran - fedin the Number and Apoptosis of Epithelial Cells in the Rats

We iRvestigated the effbct of dietary vvheat bran (Wb) on colonic turnorigenesis soon after a singie administration of 1,2-dimethylhydrazine (DMH). Rats that had been fed on either a fiber-free diet or a 20% Wb diet were injected with 1,2-dimethyihydrazine (20mgfkg bedy weight). At 6h, l2h, 1 d, 3d, or 7 d after the injeetion, the colorectum was excised for histological analyses. The numbeT of crypt cells more rapidly recovered in the 20% Wb group than in the fiber-free group after its temporary reduction by injection of DMH. At 6h after the DMH treatment, the apoptotic cells were significantly greater in number in the fiber-free gret]p than in the 20% Wb gToup. In centrast, those in distal colon were significantly fewer in the fibeT-free group than in the 20'Y6 Wb group at 7d after the treatment. These results suggest that the ingestion of VV'b affected the turnover ef colonic epithelial cells and wou}d thereby bring abeut a protective effeet again$t DMH-finduced tumorigenesis.