Photoinitiators enhanced 1,2-dichloropropane-induced cytotoxicity in human normal embryonic lung fibroblasts cells in vitro

Dichloromethane (DCM) and 1,2-dichloropsropane (DCP) have various uses, including being solvents for paint removers. Photoinitiators are also used in a wide range of commercial applications such as printing. These chemicals have been shown to induce cytotoxic effects. In the present study, we evaluated the combined effects of DCM or DCP from paint removers and photoinitiators used in printing on normal human embryonic lung fibroblasts with the aim of preventing occupational injuries. We showed that DCP, 2,2-dimethoxy-2-phenylacetophenone (2,2-DMPAP), 2-ethylhexyl-4-(dimethylamino) benzoate (2-EHDAB), 1-hydroxycyclohexyl phenyl ketone (1-HCHPK), and methyl 2-benzoylbenzoate (MBB) induced cytotoxicity, whereas DCM and 2-isopropylthioxanthone (2-ITX) did not. In addition, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (MTMP) caused a slight increase in cytotoxicity. The combination of DCP and the four photoinitiators (2,2-DMPAP, 2-EHDAB, MBB, and MTMP) significantly induced cytotoxicity and also led to apoptosis. In conclusion, the combination of DCP and photoinitiators may increase the risk of respiratory diseases.