Protective effects of cimetidine on radiation-induced micronuclei and apoptosis in human peripheral blood lymphocytes.

The radioprotective effects of cimetidine, which has been used clinically as an antagonist of H2 receptor, on radiation-induced micronuclei and apoptosis in human peripheral blood lymphocytes (PBL) prepared from healthy donors were studied. Cells were treated with cimetidine before or after X-irradiation, and then cytokinesis-blocked micronucleus assay and flow cytometry for measurement of phosphatidylserine externalization were utilized to evaluate the radiation-induced cytogenetic damage and apoptosis. The protective effect of preirradiation treatment of cimetidine on radiation-induced micronuclei was dependent on the concentration.