CELL-CYCLE AND PLOIDY ANALYSIS IN BONE-MARROW AND LIVER-CELLS OF RATSAFTER LONG-TERM CONSUMPTION OF IRRADIATED WHEAT

Rats were fed for 4 or 90 days either with 70% freshly irradiated whea t (0.25, 0.75 or 2.25 kGy) and 30% complementary feed or with a contro l diet. None of the parameters examined (food consumption, body weight , haematological analysis, histopathological inspection of thymus, lun g, liver, spleen and kidney, DNA analysis of bone marrow cells and nuc lei from liver cells by flow cytometry) showed any statistically signi ficant association with the feeding regimen. Minor changes in ploidy o f liver cells and cell cycling of bone marrow cells were detectable (w heat-irradiation dose-dependent increase in G2/M-phase bone marrow cel ls up to 0.6%, decrease of 8C nuclei up to 1.1% in liver cells). From the pattern of alterations observed in our study, radiolytic by-produc ts of wheat irradiation with a spindle poison-like activity can be exc luded. Polyploid cells do not accumulate within the 90-day feeding per iod. The minor effects on cell cycle and ploidy observed are qualitati vely comparable with the effects seen after food restriction in animal studies. It is suggested that an altered composition of fatty acids ( the components of wheat most sensitive to irradiation) is responsible for these marginal effects. Our findings may explain the earlier findi ngs of Bhaskaram and Sadasivan (American Journal of Clinical Nutrition 1975, 28, 130-135) who reported an increase in the number of polyploi d cells in the lymphocytes of malnourished children fed irradiated whe at. The most likely mechanisms for such an effect are adaptive, consti tutively regulated processes, similar to those which respond to food r estriction, It is concluded that the consumption of irradiated wheat d oes not, therefore, pose any health risk to humans.