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.

Antidepressant effect of electroacupuncture on modulating the expression of c-Fos/AP-1 through the JNK signaling pathway.

The effectiveness and safety of electroacupuncture (EA) for depression have been identified by abundant clinical trials and experimental findings. The c-Jun-NH(2)-terminal kinase (JNK) signaling pathway is considered to be involved in the antidepressant mechanism of EA. However, the antidepressant effect of EA via modulating the expression of c-Fos/activator protein-1 (AP-1) under the condition of JNK inhibition remains unexplored. In this study, we investigated the antidepressant effect and possible mechanism of EA in regulating the expression of c-Fos/AP-1 under the condition of JNK inhibition by SP600125 in rats exposed to chronic unpredictable mild stress (CUMS). The depression-like behaviors were evaluated by the body weight, sucrose preference test (SPT), and open field test (OFT). The expression levels of c-Jun in the hypothalamus, c-Fos in the pituitary gland, and c-Fos and AP-1 in the serum of CUMS induced rat model of depression were detected by ELISA. The results indicated that treatment with EA and fluoxetine can reverse the CUMS-induced depression-like behaviors in rats and can up-regulate the expression levels of c-Jun in the hypothalamus, c-Fos in the pituitary gland, and c-Fos and AP-1 in the serum. Of note, the data demonstrated that SP600125, the inhibitor of JNK signaling pathway, can exert synergistic effect with EA in regulating CUMS-induced abnormal activation of the JNK signaling pathway. The antidepressant effect of EA might be mediated by modulating the expression of c-Fos/AP-1.

[Acupuncture improved depressive behavior by regulating expression of hippocampal apoptosis-related factors in psychological stress-induced depression rats].

OBJECTIVE: To investigate the effect of acupuncture on behavior changes and the expression of reactive oxygen species (ROS), cytochrome C, cysteine-containing aspartate-specific proteases-3 (caspase-3), apoptosis inducing factor (AIF) in the hippocampus of rats exposed to chronic restraint stress (CRS), so as to provide experimental evidence for the prevention and treatment of depression. METHODS: Thirty two male SD rats were equally randomized into control, model, acupuncture and medication (Fluoxetine) groups according to the random number table. The depression model was established by chronic psychological stress stimulation (fasting, water deprivation, chronic restraint combined with solitary raising for 28 days). Manual acupuncture stimulation (2 circles/s) was applied to "Baihui" (GV20), "Yintang" (GV29) and bilateral "Sanyinjiao" (SP6) for 2 min, followed by retaining the needles for 20 min. Rats in the medication group were treated by gavage of Fluoxetine (0.18 mg/mL, 1 mL/100 g body weight). The treatment was conducted once daily for 28 days. The depression-like behavior was evaluated by using open-field test, sucrose preference test, and body weight. The content of ROS of the right hippocampus tissue was detected by using dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay, and the expression levels of cytochrome C, caspase-3 and AIF proteins of hippocampus were determined by using Western blot. RESULTS: After 28 days' stress procedure, the depression rats in the model group showed a significant decrease in the numbers of crossing and rearing of open-field test, sucrose preference index and the body weight compared to the control group (P<0.01). The content of ROS and expression levels of cytochrome C, caspase-3 and AIF in the hippocampus of the model group were significantly increased relevant to the control group (all P<0.01). After the intervention and compared with the model group, the decreased levels of the numbers of crossing and rearing, body weight and sucrose preference index, and the up-regulated levels of content of ROS and expression of cytochrome C, caspase-3 and AIF proteins were all reversed in both acupuncture and medication groups (P<0.01，P<0.05), displaying an anti-depressant effect. The effect of acupuncture was significantly superior to that of medication in up-regulating the numbers of crossing and rearing (P<0.01, P<0.05), and in down-regulating the expression of caspase-3 (P<0.01). No significant differences were found between the medication and acupuncture groups in increasing the body weight and sucrose preference index, and in down-regulating the expression of cytochrome C and AIF proteins (P>0.05). CONCLUSION: Acupuncture intervention can significantly reduce ROS content and expression level of cytochrome C, caspase-3 and AIF proteins in the hippocampus possibly by inhibiting the chronic psychological stress-hippocampal oxidative stress-mitochondrial apoptotic pathway in psychological stress-induced depression rats, which may contribute to its effect in relieving depression.