High-dose ascorbic acid prophylaxis in workers occupationally exposed to halogenated ethers

A possible prophylactic effect of ascorbic acid (AA) was studied in a group of 77 workers occupationally exposed to carcinogens bis(chloromethyl) ether and chloromethyl methyl ether. The effect of prophylactic treatment was assessed by cytogenetic analysis of chromosome aberrations, and by determination of blastic transformation and mitotic index in peripheral lymphocytes. Blood samples were taken at the beginning and at the end of 5-month AA prophylaxis. Simultaneously synthetic resin workers and subjects without any occupational exposure were used as controls. Administration of AA in daily doses of 1 g, 5 days per week, significantly decreased the frequency of aberrant cells (AB.C.) from 3.73% to 2.13%, and increased % of blastic transformation (BT) from 59.15 to 67.26 and of mitotic index (MI) value from 1.04 to 1.42. The respective data in synthetic resin workers were 3.65 against 3.52% of AB.C., 55.82 against 63.73% of BT and 0.78 against 1.08 of MI, and in nonexposed subjects 1.64 against 1.88% of AB.C., 52.10 against 55.73% of BT and 1.07 against 1.14 of MI. Smoking habits had no clear-cut effect on detected changes. These study results have confirmed that the risk of genetic injury, if assessed by the frequency of chromosome aberrations in peripheral lymphocytes, was considerably reduced after AA prophylaxis in workers occupationally exposed to halogenated ethers.