RESUMEN
Survival of cochlear sensory epithelial cells may be regulated by inhibitor of differentiation-1 (Id1) and the N-methyl-D-aspartic acid (NMDA) receptor. However, it is unclear whether Id1 and the NMDA receptor are involved in the radiation-mediated survival of rat cochlear sensory epithelial cells. Here, we show that the percentage of apoptotic cells increased, the percentage of cells in the S phase decreased, Id1 mRNA and protein expression decreased and the NMDA receptor subtype 2B (NR2B) mRNA and protein level increased in OC1 cells after radiation. Cells infected with the Id1 gene exhibited higher Id1 mRNA and protein levels and lower NR2B mRNA and protein levels than the control cells. In contrast, after transfection of the Id1 siRNA into OC1 cells, Id1 mRNA and protein expression decreased and NR2B mRNA and protein expression increased relative to that of the control group. Additionally, treatment with ifenprodil for 24 h before radiation reduced apoptosis and increased the percentage of cells in the S phase. Our results suggest that Id1 and NR2B might regulate the survival of OC1 cells following radiation.
Asunto(s)
Células Epiteliales/efectos de la radiación , Proteína 1 Inhibidora de la Diferenciación/efectos de la radiación , Órgano Espiral/efectos de la radiación , ARN Mensajero/efectos de la radiación , Receptores de N-Metil-D-Aspartato/efectos de la radiación , Animales , Apoptosis/efectos de los fármacos , Apoptosis/efectos de la radiación , Línea Celular , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/efectos de la radiación , Cóclea/metabolismo , Células Epiteliales/efectos de los fármacos , Células Epiteliales/metabolismo , Antagonistas de Aminoácidos Excitadores/farmacología , Proteína 1 Inhibidora de la Diferenciación/genética , Proteína 1 Inhibidora de la Diferenciación/metabolismo , Órgano Espiral/citología , Órgano Espiral/efectos de los fármacos , Órgano Espiral/metabolismo , Piperidinas/farmacología , ARN Mensajero/metabolismo , ARN Interferente Pequeño , Ratas , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Fase S/efectos de los fármacos , Fase S/efectos de la radiación , TransfecciónRESUMEN
OBJECTIVE: To observe the expression of corticotropin-releasing factor-1 receptor in hippocampus of rats model of salicylate induced tinnitus. METHOD: Twenty-four rats were randomly divided into three groups, eight for each group. For Group A and Group B, 10% salicylic sodium solution was intraperitoneal injected each day at the dose of 350 mg/kg for 21 days in Group A and 14 days in Group B. Group C received intraperitoneal injection with the same amount of saline solution each day for 14 days. ABR were tested 2 days before, and 2 hours after the first administration and after the last injection. Immunohistochemical test and Western Blot were utilized to detect the expression of CRF1R in hippocampus for each group. RESULT: ABR thresholds tested 2 days before the first administration of the 3 groups showed no statistically significant difference (P > 0.05). At the time point of 2 hours after the first injection, the ABR thresholds of Group A and Group B rose by 25.90 dB SPL and 25.03 dB SPL compared with that before the administration, respectively (P < 0. 01). After the last administration, the ABR thresholds of Group A and Group B rose 34.91 dB SPL and 32.62 dB SPI. compared with that before the administration, respectively (P < 0.01). The ABR thresholds of Group C showed no significant statistical difference at all the tested time points (P > 0.05). Immunohistochemical test and Western Blot revealed that the expression level of CRF1R in the hippocampus was A > B > C (P < 0.05). CONCLUSION: The expression of CRF1R in the hippocampus of salicylate induced tinnitus rat increased with the injection time, illustrating that CRF1R may participate in the mechanism of tinnitus involving the limbic system.
