Xue-Jie-San alleviates Crohn's disease through suppressing endothelial cell pyroptosis via the TLR4/NF-κB/NLRP3...

Chinese herbs with the effects of promoting blood circulation and removing stasis play a vital role in CD treatment. However, research on the mechanisms by which they work is rare. Xue-Jie-San (XJS) has exhibited excellent efficacy in ameliorating CD, but how it works is unclearly known.

The present study attempted to investigate whether XJS treating CD by restoring the function of the endothelial barrier through hindering NLRP3 inflammasome-mediated pyroptosis and uncover the potential mechanisms of blood-activating and stasis-removing herbs in treating CD.

Lipopolysaccharide-stimulated human umbilical vein endothelial cells and CD rats were subjected to XJS treatment. Colitis symptoms were recorded and histopathological damages were evaluated by hematoxylin-eosin staining. The function of vascular endothelial barrier was assessed via detecting vascular permeability and the levels of tight junction proteins through immunofluorescence staining and Western blot. Enzyme-linked immunosorbent assay was utilized to detect IL-1β and IL-18 concentrations. Endothelial cell pyroptosis and NLRP3 inflammasome activation mediated by TLR4 signaling were detected through multiple detection techniques.

XJS treatment mitigated the symptoms and histopathological damages of CD-like colitis. The function of vascular endothelial barrier was restored by XJS via reducing its permeability and upregulating the expressions of tight junction protein ZO-1 and OCLN. Pyroptosis-mediated inflammatory response was suppressed as reflected by decreased IL-1β and IL-18 concentrations. Meanwhile, the upregulated expressions of pyroptosis executor GSDMD and GSDMD-N were also precluded by XJS. Additionally, XJS administration inhibited the NLRP3 inflammasome activation via diminishing the expressions of NLRP3, ASC, pro-caspase1 and caspase1. The canonical upstream TLR4/MyD88/NF-κB signal that transcriptionally regulated NLRP3 expression was also blocked. In vitro, overexpressing TLR4 abolished the effect of XJS on inhibiting endothelial cell pyroptosis.

XJS might ameliorate CD-like colitis via restoring vascular endothelial barrier through regulating TLR4 signaling and debilitating the activity of NLRP3 inflammasome. This work disclosed a potential mechanism of blood-activating and stasis-removing herbs in treating CD.