Abstract
Background. Human mucosal biopsies are established in ecogenotoxicological studies, but up until now they have demanded immediate processing after harvesting. We report our experience with the preservation of specimens either for 24 h at 4degreesC or for longer periods at -80degreesC and compare the results with fresh specimens using the alkaline single cell microgel electrophoresis assay. ...
Abstract
Background. Human mucosal biopsies are established in ecogenotoxicological studies, but up until now they have demanded immediate processing after harvesting. We report our experience with the preservation of specimens either for 24 h at 4degreesC or for longer periods at -80degreesC and compare the results with fresh specimens using the alkaline single cell microgel electrophoresis assay. Patients and methods. Nasal mucosa was harvested from ten patients, transferred to the laboratory and divided into groups for immediate processing, 24 h preservation at 4degreesC and cryopreservation at -80degreesC. Alkaline single cell microgel electrophoresis assays were performed after separating the specimens into single cells and after exposure to benzo[a]pyrene, benzo[a]pyrene-diolepoxide, N-nitrosodiethylamine, or sodium dichromate. The trypan blue exclusion test was used to assess cytotoxicity. Results. Despite of the fact that cell viability remained stable, after cryopreservation DNA-migration increased significantly for the negative control and benzo[a]pyrene. Although an increase was also seen for sodium dichromate, this was not significant. For benzo[a]pyrene-diolepoxide, N-nitrosodiethylamine and N-methyl-N'-nitro-N-nitrosoguanicline there were no significant changes in DNA-migration. After 24 h in cell medium at 4degreesC, DNA-migration did not rise compared to the samples which were immediately processed. Conclusions. Preservation of mucosal specimens at 4degreesC for 24 h may be legitimate in order to facilitate laboratory practice. However, cryopreservation should not be applied because it leads to higher rates of DNA migration in some tested substances in the alkaline single cell microgel electrophoresis assay.
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