AN IMPROVED CHEMICAL SUBSTITUTE FOR FETAL CALF SERUM FOR THE MICRONUCLEUS TEST

The routine use of the micronucleus test in the mutagenicity evaluatio n of xenobiotics is limited by high cost and limited availability of f etal calf serum. On the other hand, there are disadvantages, such as h ypotonic damage and clumping of cells, associated with the use of mine ral medium substitutes for fetal calf serum. Alternatively, we recomme nd a chemical medium containing Hanks' buffered salt solution, 1% (w/v ) bovine serum albumin, and 0.15% (w/v) ethylenediaminetetraacetic aci d, final pH 7.4, to preserve morphology, density and homogeneity of bo ne marrow cells. Mast cell granules are efficiently removed from rat b one marrow preparations by washing twice with this medium. The morphol ogical preservation of cells is further enhanced by fixation with 70% (v/v) ethanol for 5 min. The proposed medium provides a cost-effective and convenient substitute for fetal calf serum with substantially imp roved quality of bone marrow preparations for the micronucleus test.