BuyangHuanwu decoction (BYHWD), a traditional Chinese medicine (TCM) prescription, has long been used clinically to aid neuroprotective effects after stroke. According to experimental reports, BHD improves blood circulation, controls pain, regenerates neuronal cells10-12.And protects against the neuronal damage caused by ischemic and oxidative stress13,14.BYHWT have been traditionally used to treat cognitive deficits and other brain disorders in TCM owing to the virtues of neuroprotection, anti-oxidative stress anti-apoptosis, anti-inflammation and neurotrophic actions5,14-17.Our research it is, or at least partially, helpful to better comprehend the effective underlying mechanisms of classical prescription.
In the present research, we found that BYHWD was effectively to inhibit LPS induced inflammatory responses in BV2 microglia cells. We noted that BYHWD under 9 mg/ml showed no toxicity to BV2 microglial cells. It could significantly reduce LPS-induced morphological changes and inhibit the production of pro-inflammatory cytokines and free radical. LPS is the most widely used inflammatory mediator, which can activate microglia and trigger the pro-inflammatory signaling cascade
In the present research, we found that BYHWT was effectively to inhibit LPS induced inflammatory responses in BV2 microglia cells. We noted that BYHWT showed no toxicity to BV2 microlial cells. It could significantly reduce LPS-induced morphorlogical changes and inhibit the production of pro-inflammtory cytokines and free radical. LPS is the most widely used inflammatory mediator, which can activate microglia and trigger the pro-inflammatory signaling cascade 18. In normal states, microglia surveils the microenvironment whilst maintains the homeostasis in the brain. While in disease states, in response to injury, harmful toxins, infection or inflammation, microglial cells secret pro-inflammatory mediators, which are regulated by the transcription factor nuclear factor kappa B (NF-κB), to amplify neuroinflammation and result in pathological changes. NF-κB is the central regulator of inlammation that controls the gene transcription of chemokines, cytokines, proinflammatory enzymes, adhesion molecules and proinflammatory transcription factors 19,20. Consistently, we observed that NF-κB was activated in BV2 microglia cells and resulted in the generation of proinflammatory cytokines (IL-6 and IL-1β) and inducible enzymes (iNOS), as well as nitric oxide (NO). In resting cells, the inhibitors of κB (IκB) family sequesters NF-κB in the cytoplasm. LPS activates a complex of IκB kinases (IKK) and results in the phosphorylation of IκB protein, which is rapidly ubiquitinated and degraded 21. This alteration leads to the phosphorylation of NF-κB p65 at Ser536 and the release of NF- κB from IκB. Liberated NF- κB then translocates to the nucleus and binds to specific gene promoter elements to initiate transcription 22. Therefore, the regulation of NF-κB is crucial in neuroinflammation-relatted diseases control 23. Our data displayed that SYG was effective in regulating the activity of NF- κB.
Moreover, activated NF-κB enhances the transcriptional level of cytosolic innate immune signaling receptor NOD-, LRR- and pyrin domain-containing 3 (NLRP3), a pivotal mediator of IL-6-associated neuroinflammation24,25.Targeting NLRP3 pathway is also a promising strategy to develop pharmacotherapy for inflammation-associated diseases. Our finding indicated that BYHWT could inhibit local synthesis of IL-6 by suppressing the formation of NLRP3 inflammasome and overexpression.
In conclusion, our results demonstrated that BYHWD is a potential candidate for treating neuroinflammation-related diseases via directly regulating NF-κB activity and inflammasome assembly. Certainly, more comprehensive researches on the precise mechanism of action of BYHWD in cerebrovascular disease is required in future vivo studies.