INVIVO STUDIES ON CHEMICALLY-INDUCED ANEUPLOIDY IN MOUSE SOMATIC AND GERMINAL CELLS

Within the context of a coordinated program to study aneuploidy induct ion sponsored by the European Community, nine chemicals were tested in mouse bone marrow and spermatocytes after intraperitoneal injection. In somatic cells, cell progression delay, hyperploidy, polyploidy indu ction and induction ot micronucleated polychromatic erythrocyte (MnPCE ) were studied. In germ cells hyperploidy induction was evaluated. The chemicals selected were: colchicine (COL), econazole (EZ), hydroquino ne (HQ), thiabendazole (TB), diazepam (DZ), chloral hydrate (CH), cadm ium chloride (CD). pyrimethamine (PY) and thimerosal (TM). Using liter ature data on c-mitotic effects in bone marrow as a reference, the sam e doses were tested in somatic and germ cells in order to compare the effects induced. Bone marrow cells were sampled 18 or 24 h after treat ment. Germ cells were sampled 6, 8 or 18 h after treatment. Effects of COL and HQ in bone marrow have been reported elsewhere. Somatic effec ts were induced by CH (hyperploidy and cell cycle lengthening), TB (Mn PCEs and cell cycle lengthening) and by PY (MnPCEs). EZ, DZ, CD and TM did not induce any kind of somatic effects. An increase in the incide nce of hyperploid spermatocytes was induced by COL, at three dose leve ls, and by one dose of HQ and TB. All the other chemicals did not indu ce germinal aneuploidy at any dose or time tested. The hyperploidy con trol frequency ranged between 0.4 and 1.0% in somatic cells and from 0 .3 to 0.9% in germ cells. In both somatic and germ cells, the maximum yield of induced hyperploidy did not exceed 3.5%. The time period of t arget cell sensitivity is probably restricted and this, associated wit h the heterogeneity and the asynchrony of cellular maturation processe s, may account for our data. Under these circumstances, the negative d ata should be interpreted with some caution, particularly in germ cell s, where additional indicators of chemical-cell interaction and cell c ycle effects were not provided by standardized approaches. The possibi lity of increasing the size of analyzed cell samples could be consider ed in the light of automatic scoring procedures.