Hydrogen suppresses oxidative stress by inhibiting the p38 MAPK signaling pathway in preeclampsia

Hypertensive disorders complicating pregnancy (HDCP) are one of the most serious medical disorders during pregnancy.

To investigate the effects of hydrogen on the mitogen-activated protein kinase (MAPK) signaling pathway in preeclampsia (PE).

The N(omega)-nitro-L-arginine methyl ester (L-NAME)-induced PE model with Sprague Dawley (SD) rats was employed. An inhibitor of MAPK signaling pathways (SB203580) was used as a p38 MAPK inhibitor. The SD rats were randomized into 5 groups: non-pregnant (NP); normal pregnancy (P); pregnancy + L-NAME (L); pregnancy + L-NAME + hydrogen-rich saline (LH); and pregnancy + L-NAME + hydrogen-rich saline + SB203580 (LHS). The pregnancies were terminated on day 22 of gestation, and the placentas and kidneys were microscopically inspected. Tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and malondialdehyde (MDA) levels were assessed. The mean systolic blood pressure (SBP) and level of proteinuria were recorded. The p38 MAPK mRNA expression and p-p38 MAPK protein levels were measured using real-time polymerase chain reaction (RT-PCR) and western blot, respectively.

It was found that hydrogen-rich saline (LH group) decreased placental MDA, proteinuria, TNF-α, and IL-1β levels in the placental tissues compared with the L group (all p < 0.05). Additionally, hydrogen-rich saline (LH group) treatment significantly decreased the p38 MAPK mRNA expression and p-p38 MAPK protein levels compared with the L group (p < 0.05). The p38 MAPK inhibitor SB203580 (LHS group) further decreased the p38 MAPK mRNA expression and p-p38 MAPK protein levels compared with the LH group (p < 0.05).

Hydrogen can decrease the reactive oxygen species (ROS) content and inhibit the MAPK pathway. The protective effect of hydrogen may be associated with the inhibition of the p38 MAPK signaling pathway.