1989 Volume 44 Issue 5 Pages 1021-1030
The author conducted an experimental study of the cell differentiation inducibility of some environmental chemical substances which currentry draw attention because of their influences on the human body, using an azaguanine-resistant PCC4 cell line, a clone derived from mouse teratocarcinoma OTT 6050. Cells in monolayer culture or suspension culture were exposed to the test substances and the survival and morphological changes of the cells were determined.
It was extremely rare that embryonal carcinoma cells exposed and cultured in a monolayer showed differentiation in the control group, with the rate of both epithelial cell-like and fibroblast-like morphological changes being less than 1%. Cells cultured in normal medium following exposure and incubation in suspension culture showed various patterns of differentiation according to the type and concentration of the test substance.
In the cell groups exposed to mono, di-methylformamide, fibroblast-like differentiation was observed most frequently, while little or no epithelial differentiation was seen. These findings were in contrast to those observed in the cell groups exposed to mono, di-methylacetamide.
For dimethyl sulfoxide it is considered that there is a relatively limited range of optimal concentration for differentiation induction within the concentration range which is free from cell toxicity. Polybrene and diethylene glycol were proven to have low differentiation inducibility.
As to the differentiation induction potency of extracts (tar) of granules in exhausts from light-duty (4 cylinder) and heavy-duty (6 cylinder) diesel engines, no concentration-response relation was seen for the differentiation inducibility of light-duty tar and no constant tendency was observed for heavy-duty tar. However, for epithelial differentiation both light-duty tar and heavy-duty tar showed dose-response relations.
It is currently difficult to interpret completely the significance of differentiation inducibility. However, from the viewpoint of the effect on genes it is doubtlessly not unrelated to mutation, carcinogenecity and aging. It will be useful therefore, to perform this kind of experiment in the future also on selected environmental chemical substances.
