Hydrogen sulfide in paraventricular nucleus attenuates blood pressure by regulating oxidative stress and inflammatory cytokines in high salt-induced hypertension

Hydrogen sulfide (H₂S) is an important gaseous signaling molecule in neuro-modulation, anti-inflammatory, anti-oxidant and anti-hypertensive effects. The paraventricular nucleus (PVN) is a major integrative nucleus in regulating BP and SNA. The aim of this study is to explore whether endogenous or exogenous H₂S changed by hydroxylamine hydrochloride (HA) or GYY4137 infused in the PVN affects RSNA and MAP by regulating oxidative stress or the balance between pro-inflammatory cytokines (PICs) and anti-inflammatory cytokines in high salt-induced hypertensive rats. Male Dahl rats were fed by high-salt or normal-salt diet. At the end of the 4th week, GYY4137, HA or vehicle was microinjected into bilateral PVN for 6 weeks. The levels of MAP, HR, plasma norepinephrine (NE), reactive oxygen species (ROS), NOX2, NOX4 and IL-1β were increased significantly in high salt-induced hypertensive rats. Higher levels of these parameters were detected in the group treated by HA, but lower levels in the GYY4137 group. The trends of H₂S, CBS, IL-10 and Cu/Zn SOD were opposite to the parameters described above. These findings suggest that endogenous or exogenous H₂S in the PVN attenuates sympathetic activity and hypertensive response, which are partly due to decrease of ROS and PICs within the PVN in high salt-induced hypertension.