RESUMEN
Purpose: Wolfiporia cocos is frequently used in traditional Chinese medicine to treat depression. However, antidepressant-like effects of the main active ingredients of Wolfiporia cocos, total triterpenes of Wolfiporia cocos (TTWC), are not well studied. This study aimed to investigate those effects and explore their specific mechanisms of action in depth. Methods: Chemical components of TTWC were analyzed using LC-MS. Depression-like behavior in rats were induced by chronic unpredictable mild stress (CUMS). The suppressive effects of TTWC (60, 120, 240 mg/kg) against CUMS-induced depression-like behavior were evaluated using the forced swimming test (FST), open field test (OFT) and sucrose preference test (SPT). Levels of 5-hydroxytryptamine (5-HT), glutamate (GLU), corticotropin-releasing hormone (CRH), interleukin-1 beta (IL-1beta), interleukin-18 (IL-18), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in different groups were determined by ELISA. Western blotting (WB) was used to detect the expression of NLRP3, ASC, pro-caspase-1, caspase-1, pro-IL-1beta, IL-1beta, pro-IL-18, and IL-18 in the prefrontal cortex. Additionally, the mRNA levels of NLRP3, ASC, caspase-1, IL-1beta and IL-18 were detected by RT-PCR. Results: A total of 69 lanostane-type triterpene acids of TTWC were identified. The results showed that TTWC exhibited an antidepressant-like effect in CUMS rats, reversed the decreased sugar preference in the SPT, reduction of immobility time in the FST, reduced the rest time, increased the total moving distance in the OFT. TTWC increased 5-HT levels and decreased GLU levels in the hippocampus. Moreover, TTWC decreased CRH levels in serum, indicating the regulation of over-activation of the hypothalamic-pituitary-adrenal (HPA) axis. In addition, reduced serum levels of IL-1beta, IL-18, IL-6, and TNF-alpha. The WB results implied that TTWC inhibited the expression of NLRP3, ASC, caspase-1, IL-1beta, and IL-18 in the prefrontal cortex and enhanced the expression of pro-caspase-1, pro-IL-1beta, and pro-IL-18. Although most of the results were not significant, PCR results showed that TTWC inhibited the expression of NLRP3, ASC, caspase-1, IL-1beta, and IL-18 in the prefrontal cortex. Conclusion: TTWC treatment exerted an antidepressant-like effect and regulates neurotransmitters, HPA axis and NLRP3 signaling pathway. These results indicated the potential of TTWC in preventing the development of depression.
RESUMEN
The rats were exposed to chronic unpredictable mild stress(CUMS) and kept in separate cages for inducing depressive disorder, which was judged by behavioral indicators. The number and morphology of neurons in hippocampal CA3 area and prefrontal cortex were observed by hematoxylin-eosin(HE) staining. The levels of brain-derived neurotrophic factor(BDNF), 5-hydroxytryptamine(5-HT), 5-hydroxyindoleacetic acid(5-HIAA), dopamine(DA), norepinephrine(NE), glutamic acid(GLU), interleukin-1ß(IL-1ß), interleukin-18(IL-18), and tumor necrosis factor-α(TNF-α) were detected by enzyme-linked immunosorbent assay(ELISA). Real-time polymerase chain reaction(RT-PCR) and Western blot were conducted to determine the mRNA and protein expression levels of related molecules in NLRP3 pathway. The results showed that compared with the model group, acidic polysaccharides from Poria at the low-, medium-, and high-doses(0.1, 0.3 and 0.5 g·kg~(-1)·d~(-1)) all improved the depression-like behavior of rats, increased the number of neurons and the levels of BDNF, 5-HT, 5-HIAA, DA, and NE in the hippocampus, and reduced GLU and serum IL-1ß, IL-18, and TNF-α levels. The mRNA expression levels of ASC, caspase-1, IL-1ß, and IL-18 and the protein expression levels of NLRP3, ASC, caspase-1, IL-1ß, and IL-18 in each medication group were down-regulated, whereas the protein expression levels of pro-caspase-1, pro-IL-1ß, and pro-IL-18 were up-regulated. All these have indicated that acidic polysaccharides from Poria exerted the antidepressant effect possibly by regulating neurotransmitters and NLRP3 inflammasome signaling pathway.
