Extracellular vesicles enhance oxidative stress through P38/NF-kB pathway in ketamine-induced ulcerative cystitis.

Long-term abuse of ketamine causes ketamine-induced cystitis. The functional alterations of bladder epithelial cells in microenvironment during cystitis remain poorly understood. Here, we explored extracellular vesicles (EV) alteration in ketamine-induced toxicity. To simulate the high-concentration ketamine environment in vivo, we established an in vitro model of high ketamine using human uroepithelial cells (SV-HUC-1). Cell viability and proliferation were assessed to evaluate the effects of various concentrations (0, 0.25, 0.5, 1, 2, 4 and 8 mmol/L) of ketamine on SV-HUC-1 cells. The cell supernatant cultured at a concentration (0, 1, 2, 4 mmol/L) of ketamine was selected for EV extraction and identified. Subsequently, we assessed different groups (ketamine, ketamine plus EV blocker, EV, EV plus extracellular vesicles blocker) of oxidative stress and expression of inflammation. Last, luciferase reporter assay was performed to study the transcriptional regulation of EV on the NF-kB and P38 pathway. The results of our study suggested that treatment with 0, 1, 2 or 4 mmol/L ketamine altered the morphology and secretion capacity of extracellular vesicles. As the concentration of ketamine increased, the average particle size of EV decreased, but the crest size, particle concentration and EV protein increased. Moreover, after the addition of EV blocker, EV secreted at different concentrations were blocked outside the cell membrane, and the degree of oxidative stress decreased. Our study provided evidence that ketamine alters the secretion of EV by directly stimulating cells in inflammation microenvironment and EV play significant roles in intercellular signal communication and the formation of KIC.EV.