Molecular stress response in the CNS of mice after systemic exposure to interferon-alpha, ionizing radiation and ketamine.

We previously showed that the expression of troponin T1 (Tnnt 1) was induced in the central nervous system (CNS) of adult mice 30min after treatment with ketamine, a glutamate N-methyl-D-aspartic acid (NMDA) receptor antagonist. We hypothesized that Tnnt 1 expression may be an early molecular biomarker of stress response in the CNS of mice. To further evaluate this hypothesis, we investigated the regional expression of Tnnt 1 in the mouse brain using RNA in situ hybridization 4h after systemic exposure to interferon-alpha (IFN-alpha) and gamma ionizing radiation, both of which have be associated with wide ranges of neuropsychiatric complications. Adult B6C3F1 male mice were treated with either human IFN-alpha (a single i.p. injection at 1 x 10(5)IU/kg) or whole body gamma-radiation (10cGy or 2Gy). Patterns of Tnnt 1 transcript expression were compared in various CNS regions after IFN-alpha, radiation and ketamine treatments (previous study). Tnnt 1 expression was consistently induced in pyramidal neurons of cerebral cortex and hippocampus after all treatment regimens including 10cGy of ionizing radiation. Regional expression of Tnnt 1 was induced in Purkinje cells of cerebellum after ionizing radiation and ketamine treatment; but not after IFN-alpha treatment. None of the three treatments induced Tnnt 1 expression in glial cells. The patterns of Tnnt 1 expression in pyramidal neurons of cerebral cortex and hippocampus, which are both known to play important roles in cognitive function, memory and emotion, suggest that the expression of Tnnt 1 may be an early molecular biomarker of induced CNS stress.