Postconditioning with inhaled hydrogen attenuates skin ischemia/reperfusion injury through the RIP-MLKL-PGAM5/Drp1 necrotic pathway.

This study explored the flap-protective effects of high concentrations of hydrogen (HCH) inhalation in a rat flap ischemia/reperfusion (I/R) injury model and the potential mechanism of necroptosis. Forty-five male Sprague-Dawley rats were randomly divided into three groups: SH, IR and HCH groups. After undergoing 3 h of I/R management, the surgery groups were treated with ambient air (SH and IR) and high concentrations of hydrogen (HCH). On the third postoperative day, blood perfusion in the flap was measured using Laser Doppler flowmeters. RIP1, RIP3, MLKL, PGAM5 and Drp1 were examined by immunological detection and RT-qPCR. Compared to the IR group, larger areas of the skin flaps from the SH and HCH groups survived and displayed more blood perfusion. RIP1, RIP3, MLKL, PGAM5 and Drp1 were expressed at high levels in the IR group, and their expression was significantly decreased in the HCH group. In the SH and HCH groups, the necrotic factors measured here showed similar expression levels, which were significantly lower than the levels in the IR group, indicating that HCH-mediated protective effects on rat skin I/R necrosis may be associated with the necrotic pathway.