A comparative study of synchronised and conventional culture methods on the micronucleus dose-response curve.

Micronucleus (MN) dose-response curves have been studied in blood samples obtained from a healthy volunteer with both a methotrexate synchronised culture and with a conventional culture method. The curve obtained with the synchronised culture, showed better response at higher doses compared to that obtained with the conventional procedure. Generally, MN frequency obtained at a dose of 4.0 Gy with the conventional procedure is lower, compared to that obtained with dicentric (DC) frequency. The present study also showed that MN frequency obtained at this dose was lower (0.79 +/- 0.09) compared to that obtained with DC frequency (0.91 +/- 0.10). However, DC frequency obtained with the synchronised culture was almost the same as that obtained with the conventional method, whereas acentric frequency showed an increase with the synchronised culture. The study showed that the ratios of MN frequency/total aberration frequency observed with the synchronised (0.63) and that obtained with the conventional culture (0.59) was more or less the same indicating that higher acentric frequency may be the cause for higher MN frequency in the synchronised culture. The present study indicates that methotrexate may not be the cause of higher acentric frequency in synchronised culture. A possible reason for the higher acentric frequency in the synchronised culture, is highlighted.