Effects of mineral fibres in an in vitro placental syncytiotrophoblast model

It is known that mineral fibres can be found in placental tissues, but their effect is not known on these tissues. BeWo in vitro model of syncytiotrophoblast, the outer layer of maternal-foetal barrier, is necessary to understand if mineral fibres can alter placental cell turnover and consequently to influence the outcome of pregnancy. We performed in vitro experiments using chrysotile UICC (UICC), chrysotile Valmalenco (VM) and erionite (ERI) to investigate the potential cytotoxic effects of these mineral fibres on BeWo cells. We demonstrated that all fibres are toxic while only UICC fibres caused a DNA damage that the cells were not able to repair through RAD51 activity. In addition, we demonstrated that DNA replication is not altered while cyclin D1 showed a significant decrease in VM and UICC suggesting that the cell cycle is altered in G1 phase. Moreover, UICC increased active form of caspase 3 demonstrating that apoptosis can be induced in BeWo cells. We suggest that although morphological changes are not visible in BeWo cells treated with these mineral fibres, DNA damage can lead to altered placenta physiology that can be seen late when the damage at the foetal tissues has already occurred.