Objective To investigate the changes in mitochondrial morphology, structure and function in rats with severe intermittent hypoxia, as well as the effects of intermittent hypoxia and its severity on cognitive function. Methods A total of 18 rats were selected to construct a model of severe intermittent hypoxia, which were divided into a normal control group, an intermittent air control group, and a 5% intermittent hypoxia group for 8 weeks, with 6 rats in each group. The structural and functional changes of mitochondria in the hippocampal CA1 region were observed. A total of 30 rats were randomly divided into 5 groups: a normal control group, an intermittent air control group, a 5% intermittent hypoxia 4-week group, a 5% intermittent hypoxia 6-week group, and a 5% intermittent hypoxia 8-week group, with 6 rats in each group. The cognitive function of the rats in each group was evaluated by Morris water maze experiment. Results In the mitochondria of the hippocampal CA1 region of severely intermittent hypoxic rats, bilayer membranes or multilayer membranes were visible, the mitochondria were swollen, cristae were broken and vacuolated, and their respiratory function was significantly weakened, the membrane permeability was increased, and the membrane potential was reduced. In the Morris water maze, there was no significant difference in swimming speed between the rats. With the prolongation of intermittent hypoxia action time, the latency of finding the hidden platform in each group of rats increased significantly, and the residence time of the target quadrant decreased significantly. Conclusions Mitochondrial structure in the hippocampal CA1 region of the rat brain is destroyed during severe intermittent hypoxia, and dysfunction and cognitive impairment occur. With the prolongation of intermittent hypoxic injury, the degree of cognitive impairment worsens.
