Protective effect of Aster tataricus extract on NLRP3-mediated pyroptosis of bladder urothelial cells

Aster tataricus L.f. is a traditional Eastern Asian herbal medicine used for the relief of uroschesis-related illnesses and has been demonstrated clinically to exert satisfied effects. However, the mechanism of its therapeutic action remains unclear. The present study aimed to evaluate the protective mechanism of Aster tataricus extract (ATE) on CYP or LPS + ATP-induced interstitial cystitis (IC), we successfully constructed the induced IC Sprague-Dawley (SD) rat model and IC human urothelium cell (SV-HUC-1) model. The main compounds of ATE were determined by LC-MS. After intervention, the changes on the bladder wall morphology and inflammation were observed in each group. SV-HUC1 cell viability was measured by MTT and double stained with Hoechst 33342 and propidium iodide (PI). The expression levels of NLRP3, Pro-caspase-1, Caspsae-1 p20, GSDMD, GSDMD-N and Cleave-IL-1β in vivo and in vitro in different groups were detected by Western blotting. ATE significantly alleviated oedema and haemorrhage and reduced the inflammation index and histopathological score in SD rat bladder. The results of cell revealed that ATE could improve cell viability and decrease pyroptosis ratio. The expression of NLRP3 and other pyroptosis-related protein was remarkably decreased by ATE both in vivo and in vitro. ATE may be used as an inhibitor of NLRP3 in treating IC. The discovery of NLRP3/Caspase-1/GSDMD-N as a new protective pathway provides a new direction for protecting cell against IC.

Keywords: ATE; NLRP3 inflammasome; interstitial cystitis; pyroptosis; urothelial cell.