OBJECTIVE: To investigate the regulation of different hypoxia on cell survival 
and autophagy.
METHODS: PC12 cells were treated with different hypoxia. The cell survival was 
measured by MTT assay, expressions of LC3 and p62 were marked for autophagy 
detected by Western Blot, and the level of reactive oxygen species (ROS) was 
analyzed by flow cytometry.
RESULTS: The cell viability was different under different hypoxia: moderate 
hypoxia promoted cell viability, and severe hypoxia caused a decrease in cell 
viability; autophagy marker molecules, p62 and LC3-II expressions were 
different: moderate hypoxia increased p62 and LC3-II expressions, in contrast, 
severe hypoxia led to the decrease of p62 and LC3-II expressions; compared to 
normoxia, moderate hypoxia did not change the levels of ROS, while severe 
hypoxia increased the levels; 3-MA, the inhibitor of autophagy, elevated the 
levels of ROS in the three oxygen concentrations, additionally, the increased 
amplitudes in the moderate and severe hypoxia groups were higher than that in 
the normoxia group.
CONCLUSION: Moderate hypoxia promotes cell survival, severe hypoxia causes the 
cell death, and the autophagy activity may mediate the effects of different 
hypoxia.