Expression changes of indoleamine 2,3-dioxy-genase in the hippocampus of rat with post-traumatic stress disorder / 中华行为医学与脑科学杂志

ABSTRACT

Objective To observe the expression of indoleamine 2,3-dioxy-genase(IDO) in hippocampus of rats with posttraumatic stress disorder (PTSD) and the protective effect of IDO inhibitor on neurons,and to explore the role of IDO in the pathogenesis of PTSD.Methods Adult male Wistar rats were randomly divided into the normal control group,PTSD model group and IDO inhibitor treatment group.The expression of IDO was detected by immunohistochemistry,RT-PCR and Western-blot.The apoptosis of rat hippocampal neurons was assayed by Tunel staining.Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected by ELISA.Moreover behavioral evaluation was performed,including central residence time,percentage of open arm residence time and stage latency.Results Comparing with the control group,PTSD rats showed decreased central residence time ((22.65± 1.54)s),decreased percentage of open arm residence time((10.55± 1.96) ％),prolonged stage latency ((56.38±4.21) s) (P＜0.05),increased TNF-α ((8.58±0.6) pg/ml),IL-6 ((15.72±1.42) pg/ml) and IDO mRNA (0.8278±0.0796),increased IDO protein (1.2329±0.1148) expression and apoptosis rate ((81.47± 6.86) ％) in hippocampus (P＜ 0.05) (P＜ 0.05).However,rats treated with IDO inhibitor showed increased central residence time((30.78±3.20) s),increased percentage of open arm residence time ((10.55± 1.96)％),shortened stage latency ((56.38 4.21) s),meanwhile reduced expression of TNF-α((3.69±0.41) pg/ml),IL-6((7.45±0.58) pg/ml),IDO mRNA(0.2236 ±0.0387) and IDO protein(0.4235±0.0411) was detected in hippocampus(P＜0.05).Apoptosis rate ((42.54± 3.98)％) was also decreased in hippocampus(P＜0.05).Conclusion The content of TNF-α,IL-6 and IDO are increased significantly in the hippocampus of PTSD rats.IDO may participate in the pathogenesis of PTSD,and the IDO inhibitor may play a neuroprotective role in hippocampus of PTSD.