Slow regulated release of H2S inhibits oxidative stress induced cell death by influencing certain key signaling molecules.

Hydrogen sulphide (H2S) is one of three gaseous signaling molecules after nitric oxide and carbon monoxide. Various H2S donor compounds have been synthesized to study its physiological function. Among these compounds sodium hydrosulphide (NaHS), a donor of releasing H2S rapidly have shown to be protective in certain neuronal cell line but several in vivo studies have generated conflicting data. Furthermore several slow releasing H2S donors have been shown to have positive effects on cells in culture. The intracellular concentration of H2S and hence its rate of production may be a factor in keeping the balance between its neuroprotective and toxic effects. The present study was undertaken to deduce how a rapid releasing H2S donor (NaHS) as opposed to a slow releasing donor (ADTOH), affect oxidative stress related intracellular components and survival of RGC-5 cells. It was concluded that when RGC-5 cells are exposed to the toxic effects of glutamate in combination with buthionine sulfoxime (Glu/BSO), ADTOH was more efficacious in inhibiting apoptosis, scavenging reactive oxygen species (ROS), stimulation of glutathione (GSH) and gluthathione-S-transferase (GST). Western blot and qPCR analysis showed ADTOH increased the levels of Nrf2, HO-1, PKCα, p-Akt, Bcl-2 and XIAP but caused a decrease of Nfκβ and xCT greater than NaHS. This study is first to compare the efficacy of two H2S donor drugs as potential neuroprotectants and demonstrate that slow regulated release of H2S to cell culture can be more beneficial in inhibiting oxidative stress induced cell death.