Mutations at HPRT loci and micronuclei induced by late fission products in peripheral blood lymphocytes of rats

Objective: The probability of mutations at HPRT loci used as a biological dosimeter was studied. Methods: With the technique of multinuclear cell and cytokinesis-block micronucleus (CBMN) method, the relationships between mutations at HPRT loci, micronucleus and accumulative doses and dose-rates were studied. Results: On the first day after intravenous injection of late fission products (accumulative dose 1.73 cSv), by comparison with the control group, the HPRT variant frequencies, micro-nucleate cell frequencies and micronucleus frequencies increased significantly (P < 0.01). There existed relationships between variant frequencies at HPRT locus, micro-nuclear cell frequencies, micronucleus frequencies and accumulative doses, which could be described by the following regression equation: Y = a + blnX, respectively. At the same accumulative dose, both the relationships between HPRT variant frequencies, micronucleus frequencies and dose-rates could be expressed by the logarithmic regression equation: Y = a + blnX. A good linear relationship between HPRT variant frequencies and micronucleus frequencies was observed. Conclusion: HPRT gene locus is an endpoint very sensitive to injurious effects resulting from late fission products and has a good dose-response relationship