Morinda officinalis oligosaccharides alleviate depressive-like behaviors in post-stroke rats. - GreenMedInfo Summary
Morinda officinalis oligosaccharides alleviate depressive-like behaviors in post-stroke rats via suppressing NLRP3 inflammasome to inhibit hippocampal inflammation.
CNS Neurosci Ther. 2021 Sep 24. Epub 2021 Sep 24. PMID: 34559953
Zhifang Li
AIMS: Morinda officinalis oligosaccharides (MOOs), a traditional Chinese medicine, have been used to treat mild and moderate depressive episodes. In this study, we investigated whether MOOs can ameliorate depressive-like behaviors in post-stroke depression (PSD) rats and further explored its mechanism by suppressing microglial NLRP3 inflammasome activation to inhibit hippocampal inflammation.
METHODS: Behavioral tests were performed to evaluate the effect of MOOs on depressive-like behaviors in PSD rats. The effects of MOOs on the expression of IL-18, IL-1β, and nucleotide-binding domain leucine-rich repeat (NLR) family pyrin domain containing 3 (NLRP3) inflammasome were measured in both PSD rats and lipopolysaccharide (LPS) and adenosine triphosphate (ATP) stimulated primary rat microglia by reverse transcription polymerase chain reaction (RT-PCR),immunofluorescence and Western blot analysis. Adeno-associated virus (AAV) was injected into the hippocampus to regulate NLRP3 inflammasome expression. The detailed molecular mechanism underlying the effects of MOOs was analyzed by Western blot and immunofluorescence.
RESULTS: MOOs can alleviate depressive-like behaviors in PSD rats. PSD rats showed increased expression of IL-18, IL-1β, and NLRP3 inflammasome in the ischemic hippocampus, while MOOs reversed the elevation. NLRP3 downregulation ameliorated depressive-like behaviors and hippocampal inflammation response in PSD rats, while NLRP3 upregulation inhibited the effect of MOOs on depressive-like behaviors and hippocampalinflammation response in PSD rats. Moreover, we found that NLRP3 was mainly expressed on microglia. In vitro, MOOs effectively inhibited the expression of IL-18, IL-1β, and NLRP3 inflammasome in LPS + ATP treated primary rat microglia. We also showed that modulation of NLRP3 inflammasome by MOOs was associated with the IκB/NF-κB p65 signaling pathway.
CONCLUSION: Overall, our study reveals the antidepressive effect of MOOs on PSD rats through modulation of microglial NLRP3 inflammasome. We also provide a novel insight into hippocampal inflammation response in PSD pathology and put forward NLRP3 inflammasome as a potential therapeutic target for PSD.