This study aims to evaluate if the treatment of placental explants with hydrogen peroxide (H2O2) is able to induce inflammasome complexes in placentas from normotensive pregnant women and then increase inflammatory cytokines expression.
Placental explants were obtained from normotensive pregnant women undergoing elective cesarean section at 39 gestational weeks (N = 10). Placental explants were cultured in different concentrations of H2O2 (10, 100, 1000, 2000 and 10,000 μM) for 4 h. Explant controls were cultured only supplemented medium. Gene expression for cytokines (IL-1β, IL-10 and TNF-α) and Caspase-1 were determined by RT-qPCR. Differences between groups were analyzed by non-parametric tests with significance level set at 5%.
Explants cultured with 1000, 2000 and 10,000 μM of H2O2 showed lower IL-10 mRNA expression than controls. On the contrary, higher gene expression of TNF-α was observed in the same concentrations. Interestingly, IL-1β mRNA expression was higher in the presence of 10 and 100 μM H2O2 concentrations than in 10,000 μM. IL-1β mRNA expression was also higher in cultures with 100 μM H2O2 concentration than in 1000 and 2000 μM. Gene expression of Caspase-1 was increased in cultures with 100 μM of H2O2 concentration.
These results suggest that the oxidative stress caused by H2O2 can activate caspase-1 wich participates in inflammasomes pathway and consequently increases the release of pro-inflammatory cytokines, such as IL-1β and TNF-α. In addition, different responses among different concentrations of H2O2 raise the importance of the oxidative stress intensity for pathological process. Financial support – FAPESP 2014/25611-5.