Fig. 4

Procyanidins suppressed morphine-induced NLRP3 inflammasome activation in microglia. BV-2 cells were stimulated by LPS (1 μg/ml) or morphine (200 μM) with or without 100 μM of procyanidins for 12 h, and then, the inflammasome was activated with 5 mM of ATP for 1 h. a Procyanidins (100 μM) inhibited both LPS-induced and morphine-induced expression of pro-IL-1β and NLRP3 in BV-2 cells. The western blot samples for BV-2 cells (n = 4) were collected and analyzed 12 h after the last morphine exposure. b Procyanidins (100 μM) inhibited the morphine-induced and LPS-induced increase of caspase-1 and IL-1β in the supernatant of BV-2 cells. The western blot samples (n = 4) came from the supernatant of BV-2 cells. c ELISA of IL-1β in supernatants from LPS- and morphine-primed BV-2 cells and then stimulated with ATP. *p < 0.05, **p < 0.01, ***p < 0.001 vs. baseline; ^# p < 0.05, ^## p < 0.01, ^### p < 0.001 vs. morphine-treated group