Serum NLRP3 Inflammasome and BDNF: Potential Biomarkers Differentiating Reactive and Endogenous Depression.

Background: The highly heterogeneous pathogenesis of depression and limited response to current antidepressants call for more objective evidence for depression subtypes. Reactive and endogenous depression are two etiologically distinct subtypes associated with different treatment responses. This study aims to explore the potential biomarkers that differentiate reactive and endogenous depressions. Methods: The clinical manifestations and biological indicators of 64 unmedicated mild-to-moderate depression patients (32 reactive depression patients and 32 endogenous depression patients) and 21 healthy subjects were observed. The 24-item Hamilton rating scale for depression (HAMD-24) was used to evaluate the severity of depression. Serum levels of depression-related biological indicators were measured by using the enzyme-linked immunosorbent assay. Results: The NLRP3 level of reactive depression was significantly lower than those of endogenous depression and healthy controls. There was a significant negative correlation between the BDNF level and the HAMD-24 total scores for patients with reactive depression. Conclusion: Our findings suggested the serum NLRP3 and BDNF levels could be potential biomarkers for detecting and evaluating the severity of reactive depression.

[Effect of Acupuncture Intervention on Depression Behavior and Expression of ERK 1/2 and BDNF in Prefrontal Cortex in Chronic Unpredictable Mild Stress Induced Depression Rats].

OBJECTIVE: To investigate the effect of acupuncture intervention on the depression behavior and expression of extracellular signal-regulated protein kinases (ERK 1/2), p-ERK 1/2 and brain-derived neurotrophic factor (BDNF) in the prefrontal cortex of chronic unpredictable mild stress (CUMS) induced depression rats, so as to explore its antidepressant mechanism. METHODS: Sixty-four male SD rats were randomly divided into control, model, acupuncture, Fluoxetine, model ＋ Dimethyl sulfoxide (DMSO), model ＋ PD 98059(an ERK pathway inhibitor), acupuncture ＋ PD 98059 and Fluoxetine ＋ PD 98059 groups (n＝8 rats in each). The CUMS depression model was established by using chronic mild and unpredictable stress methods for 21 days. Manual acupuncture stimulation was applied to "Baihui" (GV 20) and "Yintang" (GV 29) for 10 min before modeling, once daily for 21 days. Fluoxetine hydrochloride suspension (1.8 mg•kg－1•d－1) was given to rats of the Fluoxetine group and Fluo-xetine ＋ PD 98059 group by gavage 30 min before CUMS. PD 98059 (dissolved in DMSO, 10 µL) was administered to rats of model ＋ PD 98059 group, acupuncture ＋ PD 98059 and Fluoxetine ＋ PD 98059 group, and DMSO (10 µL) to rats of model ＋ DMSO group by intracerebroventricular injection 1 h before CUMS. Sucrose consumption test was carried out to evaluate the depressive behavior. Western blot was performed to detect the expression of ERK 1/2, p-ERK 1/2 and BDNF of prefrontal cortex. RESULTS: Compared with the control group, the sucrose consumption and the expression levels of p-ERK 1/2 and BDNF protein in the prefrontal cortex were significantly reduced in the model and model＋DMSO group (P<0. 01). After the intervention, modeling induced decrease of the sucrose consumption, and p-ERK 1/2 and BDNF expression was significantly up-regulated in both acupuncture and Fluoxetine groups (P<0.01, P<0.05), but not in the model＋PD 98059, Fluoxetine ＋PD 98059 and acupuncture＋PD 98059 groups (P>0.05). No significant differences were found among the model＋PD 98059, Fluoxetine ＋PD 98059 and acupuncture＋PD 98059 groups in the sucrose consumption, and ERK 1/2, p-ERK 1/2 and BDNF expression levels (P>0.05), and in the expression levels of ERK 1/2 protein among the 8 groups (P>0.05). CONCLUSION: Acupuncture intervention has an anti-depressive role in CUMS induced depression rats, which may be related to its effects in up-regulating the expression of p-ERK 1/2 and BDNF in the prefrontal cortex tissue.