Cytotoxic Effects of Two Parabens Determined in Surface Waters and Sewage Sludge on Normal (Senescent) Human Dermal Fibroblasts

Katarzyna Miranowicz-Dzierżawska
Central Institute for Labour Protection – National Research Institute (CIOP-PIB), Poland
corresponding author’s e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract
The aim of the study was to compare the cytotoxic effects of (methyl and propyl) parabens likely to be environ-mental contaminants on early and late passage fibroblasts isolated from human skin. The study was carried out on senes-cent diploid cell lines, namely normal (senescent) dermal fibroblasts CCD-1136Sk (ATCCCRL-2697TM). In order to assess the cytotoxic effect, the MTT test which determines the cells’ metabolic activity and the neutral red uptake assay which assesses the cell membrane integrity (NRU test) were applied. Propyl paraben (PrPB) appeared to be more cytotox-ic to the analysed dermal fibroblasts (since it reached lower IC50 values); however, none of the tests found a consistent trend for a change in the cells’ sensitivity to the analysed parabens as they age, that would be reflected in the determined IC50 values. On the other hand, having analysed the course of the curves of relationships between the cell viability and the preservative concentration, it was found that at the exposure of CCD-1136Sk fibroblasts to propyl paraben, none of the two tests observed different sensitivity of late and early cell passages; however, the exposure of dermal fibroblasts to methyl paraben, determined using the NRU test, indicated a stronger effect of the preservative at a concentration of 50 and 200 µg/ml on the earliest cells passage (no. 8), compared to the subsequent passages of these cells. At the same time, the compound with a concentration of 50 and 800 µg/ml was the least toxic to the latest cells passage (no. 20). The pre-sented results indicate that the analysed parabens used in the cosmetic and pharmaceutical industries may be toxic to skin cells; moreover, it is not excluded that with consecutive passaging, differences in the susceptibility to cytotoxic effects may occur. It therefore appears necessary to take into account the possibility of different later and earlier passag-es cells’ reactivity when interpreting the results of studies into the effects of preservatives on the living body. Further-more, it should be borne in mind that humans may be exposed to preservatives due to environmental contamination.

Keywords 
preservatives, methylparaben, propylparaben, cytotoxicity, senescent cells, in vitro

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