Abstract: ObjectiveTo investigate the effects of lipopolysaccharide (LPS) on the expression of ten-eleven translocation enzyme 1 (Tet1) and ten-eleven translocation enzyme 2 (Tet2) in astrocytes. MethodsAstrocytes were stimulated with LPS and/or ketamine. Their total RNA was extracted by Trizol method to detect the levels of Tet1 and Tet2 mRNA. The cells were divided into five groups: a control group, 1 mg/L and 10 mg/L LPS groups (Groups L1 and L10), a ketamine group (Group K), and a LPS plus ketamine group (Group L1+K). ResultsCompared with the control group, the level of Tet1 mRNA in cells exposed to LPS was significantly decreased, especially Group L1. No significant difference was found in Tet2 mRNA expression. In contrast, the amount of Tet1 mRNA was significantly increased in Group L1+K and Group L1. ConclusionLPS can induce the down-regulation of Tet1 mRNA expression in human astrocytoma cells which can be reversed by ketamine.