An improved chemical substitute for fetal calf serum for the micronucleus test.

The routine use of the micronucleus test in the mutagenicity evaluation of xenobiotics is limited by high cost and limited availability of fetal calf serum. On the other hand, there are disadvantages, such as hypotonic damage and clumping of cells, associated with the use of mineral medium substitutes for fetal calf serum. Alternatively, we recommend a chemical medium containing Hanks' buffered salt solution, 1% (w/v) bovine serum albumin, and 0.15% (w/v) ethylenediaminetetraacetic acid, final pH 7.4, to preserve morphology, density and homogeneity of bone marrow cells. Mast cell granules are efficiently removed from rat bone marrow preparations by washing twice with this medium. The morphological 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 improved quality of bone marrow preparations for the micronucleus test.