RESUMO
The murine local lymph node assay (LLNA) is an immunologically based test of the sensitizing potential of immunotoxicants, but also evaluates immunosuppressive potential with good sensitivity and specificity. We conducted the LLNA with calcineurin inhibitors (tacrolimus and cyclosporin A), antimetabolites (methotrexate and azathioprine), steroids (dexamethasone and prednisolone), and an alkylator (cyclophosphamide). We performed a comprehensive analysis of results of gene expression in lymph nodes obtained in the LLNA using a highly sensitive DNA chip, 3D-Gene™, and the quantitative reverse transcription-polymerase chain reaction (qPCR). Zfp459 expression increased in all animals treated with immunosuppressive chemicals. Ltf, Cbll1 and Lias expression changed specifically in response to the calcineurin inhibitors, Fmo2 and 9630033F20Rik in response to the antimetabolites, Krt8, Gjb1, Hmha1 and Sfrs7 in response to the steroids, and Gbp1 and Mup5 in response to the alkylator. Therefore, these genes were considered novel markers for immunosuppression and their expression could be used to evaluate the mechanism of action of immunosuppressive chemicals.
Assuntos
Imunossupressores/farmacologia , Ensaio Local de Linfonodo , Alquilantes/farmacologia , Animais , Antimetabólitos/farmacologia , Peso Corporal/efeitos dos fármacos , Inibidores de Calcineurina , Feminino , Expressão Gênica/efeitos dos fármacos , Marcadores Genéticos , Linfonodos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Análise de Sequência com Séries de Oligonucleotídeos , Tamanho do Órgão/efeitos dos fármacos , RNA/biossíntese , RNA/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Dodecilsulfato de Sódio/toxicidade , Esteroides/farmacologiaRESUMO
Sodium dehydroacetate (DHA-S) is used as a food additive, preservative and antimicrobial agent. Repeated oral administration of DHA-S in rats induced severe hemorrhage in multiple organs and prolongation of blood coagulation factors. To determine the mechanism of hemorrhage, the protective effect of vitamin K (VK) was investigated. Increased VK-dependent blood coagulation parameters, a prolonged prothrombin time (PT) and an activated partial thromboplastin time (APTT) were observed in rats when DHA-S alone was administered, while only a slight change was observed in animals that received a single injection of vitamin K2 following the DHA-S dosing. These results suggest that DHA-S-induced hemorrhage is caused by a deficiency of vitamin K. In addition, the inhibitory effect of DHA-S on vitamin K1 epoxide reductase (VKOR) activity was measured with an in vitro system using liver microsomes of normal male rats. DHA-S concentration-dependently inhibited VKOR activity similar to warfarin, but the inhibitory concentration was high. Therefore, it was concluded that the DHA-S-induced hemorrhage was caused by a depletion of blood VK, associated with any factors including VKOR inhibition.