Hydrogen sulfide regulates autophagy in nucleus pulposus cells under hypoxia

OBJECTIVE: Hydrogen sulfide (H(2)S) has been found to act as an important gasotransmitter to regulate cell activities. This study aimed to investigate the effect of H(2)S on autophagy of nucleus pulposus (NP) cells under hypoxia and possible mechanism. MATERIALS AND METHODS: NP cells were isolated from rat caudal discs. Cobalt chloride was used to mimic hypoxia, sodium hydrosulfide was used to emulate exogenous H(2)S and 3‐methyladenine was used to block cell autophagy. Cell viability was assessed by phase contrast microscope and Cell Counting Kit‐8 method. Moreover, expression of key autophagic proteins was analyzed via western blotting, and transmission electron microscopy was performed to detect autophagosomes. RESULTS: Hypoxia markedly impaired NP cell proliferation compared with control. Whereas H(2)S provided pro‐proliferation and pro‐autophagy effects on hypoxic NP cells. However, these beneficial impact of H(2)S on hypoxic NP cells were reversed by autophagy inhibitor. CONCLUSIONS: Our results showed that H(2)S played a cytoprotective role in NP cells exposed to hypoxia in an autophagy‐dependent manner.