RESUMO
This study was aimed to investigate the changes of the hypothalamic-pituitary-adrenal axis (HPAA) activity and the cytokines system in the hypothalamus of the depressive rats which were exposed to chronic unpredictable mild stressors (CUMS) after middle cerebral artery occlusion (MCAO). By means of qRT-PCR, ELISA and Western blot, mRNA and/or protein expressions of corticotropin releasing factor (CRF), tumor necrosis factors-α (TNF-α), suppressor of cytokines signaling 3 (SOCS3), phosphorylation of signal transducers and activators of transcription 3 (pSTAT3) were measured in the hypothalamus of rats. The results showed that, compared with control group, CUMS+MCAO group exhibited increased mRNA levels of CRF, TNF-α, SOCS3, as well as up-regulated CRF, TNF-α, SOCS3 and pSTAT3 protein expressions. Furthermore, there were correlations between CRF and TNF-α, TNF-α and SOCS3, SOCS3 and pSTAT3, respectively. These observations indicated the CRF system was activated in the post stroke depression (PSD) status. The TNF-α and its signaling pathway, STAT3/SOCS3, were up-regulated in mRNA and protein levels. In conclusion, this study presents the evidence which supports the hypothesis of signaling cross-talk between the CRF system and TNF-α signaling pathway after ischemic stroke and CUMS.