Abnormal regional brain activity in patients with first-episode medication-naïve depressive disorder: A longitudinal fNIRS study.

The potential relationship between abnormal brain activity and clinical symptoms in patients with major depressive disorder (MDD) is important for auxiliary diagnosis and prediction of the curative effect of treatments for MDD. Before antidepressant treatment (T1), 4 weeks after treatment (T2), and 8 weeks after treatment (T3), 33 patients with first-episode medication-naïve MDD and 30 healthy controls (HCs) were examined using functional near-infrared spectroscopy (fNIRS) to evaluate the cerebral hemodynamic response in the frontal and temporal cortex during the Verbal Fluency Task (VFT). Compared with HCs, VFT scores and activation levels of the frontal pole, inferior frontal gyrus, and dorsolateral prefrontal cortex were significantly decreased in the first-episode medication-naïve depressive disorder patients (FMD).

Down-regulation of MKP-1 in hippocampus protects against stress-induced depression-like behaviors and neuroinflammation.

Chronic stress is the primary environmental risk factor for major depressive disorder (MDD), and there is compelling evidence that neuroinflammation is the major pathomechanism linking chronic stress to MDD. Mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) is a negative regulator of MAPK signaling pathways involved in cellular stress responses, survival, and neuroinflammation. We examined the possible contributions of MKP-1 to stress-induced MDD by comparing depression-like behaviors (anhedonia, motor retardation, behavioral despair), neuroinflammatory marker expression, and MAPK signaling pathways among rats exposed to chronic unpredictable mild stress (CUMS), overexpressing MKP-1 in the hippocampus, and CUMS-exposed rats underexpressing MKP-1 in the hippocampus.

Enriched environment combined with fluoxetine ameliorates depression-like behaviors and hippocampal SYP expression in a rat CUS model.

Effects of enriched environment (EE) combined with fluoxetine in a chronic unpredictable stress (CUS) rat model were examined in our study. Thirty male Sprague-Dawley rats were randomly divided into control group, CUS group, CUS+EE group, CUS+fluoxetine group, and CUS+EE+fluoxetine group (n=six per group). Rats in the CUS group were bred under conditions of CUS and separation for 6 weeks; Control group animals were bred in group cages (three rats per cage) under standard laboratory conditions for 6 weeks; Rats in CUS+EE group, CUS+fluoxetine group, and CUS+EE+fluoxetine groups were bred under the conditions of CUS and separation for 6 weeks and had an intervention of EE, an oral gavage of fluoxetine, and an intervention of EE+oral gavage of fluoxetine, respectively, every day for the final 3 weeks.