Phytic acid in wheat bran affects colon morphology, cell differentiation and apoptosis

Wheat bran (WB) and its component phytic acid (PA) have both been shown to decrease early biomarkers of colon carcinogenesis, i.e. the PCNA labeling i ndex of cell proliferation and certain aberrant crypt foci parameters. Howe ver, it is not known how WE and PA alter other biomarkers of colon cancer r isk, such as rate of apoptosis and degree of differentiation, or how they a ffect colon morphology, Thus, the objectives of this study were to determin e the effects of WB on these parameters, to see if PA contributes to these effects and whether there is a difference between endogenous and exogenousl y added PA. Five groups of azoxymethane-treated male Fischer 344 rats were fed a basal control diet (BD) or ED supplemented with either 25% wheat bran , 25% dephytinized wheat bran (DWB), 25% DWB plus 1.0% PA or 1.0% PA for 10 0 days. The WE, DWB and PA diets significantly increased the rate of apopto sis and cell differentiation in the whole crypt and the top 40% of the cryp t, The WE, DWB and PA diets also significantly increased cell apoptosis in the bottom 60% of the crypt, while all the treatment groups significantly i ncreased cell differentiation versus the ED group in the bottom 60% of the crypt, In addition, the WE, DWB and PA diets decreased the number of crypts per millimeter of colon, while the DWB and PA diets also decreased crypt h eight measured as number of cells. It is concluded that WE, partly due to i ts dietary fiber and endogenous PA, and exogenous PA when added to a low fi ber diet can increase cell apoptosis and differentiation and favorably affe ct colon morphology.