Thiosalicylate decreases the expression of MT-1 mRNA in mouse cerebellar microglia cell line, C8-B4

Complete text of publication follows. Thimerosal is used worldwide as a vaccine preservative. In the body, thimerosal splits into two compounds, thiosalicylate (TSA) and ethyl mercury. We observed the effect of thimerosal and its metabolites on the expression of metallothionein (MT) mRNA using mouse cerebellar microglia cell line, C8-B4 cells, as MT-1 and MT-2 are known to be acute-phase proteins and are induced simultaneously in the brain in response to various stimuli including metals. TSA was observed to decrease the expression of MT-1 mRNA but not MT-2 mRNA. Furthermore, the effect of TSA on MT-1 mRNA was observed in C8-B4 cells, but not in NG108-15 neuroblastoma cells. It is thought that the same transcriptional factors act on MT-1 and MT-2 genes. In addition, it is known that the levels of MT-1 and MT-2 are reduced in several carcinomas including the primary human hepatocellular carcinoma. When TSA was added to C8-B4 cells, cell viability increased. Silencing of the MT-1 gene, not the MT-2 gene, may be related to cell proliferation and carcinogenesis. In conclusion, TSA clearly has a different action to the expression of MT-1 mRNA and MT-2 mRNA in C8-B4 cells.