Abstract: Objective To investigate the effect of grape seed proanthocyanidin extract (GSPE) on ultrastructure injury in hippocampous and cognition impairment in rat model of obstructive sleep apnea hypoxia. Methods 80 male Sprague-Dawley rats were randomly divided into control group, model group, high and low dose GSPE groups. The control group was exposed in air, while the model group was suffered from intermittent hypoxia conditions (50 ml/L, 8 h everyday, for 2 or 6 weeks), and the GSPE groups accepted GSPE 200 mg/kg or 100 mg/kg 2 weeks respectively before hypoxia. Pathology in hippocampal region was observed under electromicroscope. Malondialdehyde (MDA) contents and superoxide dismutase (SOD) activity were detected with colorimetry, and apoptotic cells were measured with TUNEL. The cognition function of rats was assessed with the Morris water maze (MWM). Results The ultrastructure in hippocampous was significantly injured,with the increase of MDA and decrease of SOD (P<0.001) in the model group. The apoptotic cells increased (P<0.001). The escaping latency prolonged (P<0.001) and the frequency of crossing the platform decreased (P<0.001) in MWM test in the model group. Compared with the model group, the GSPE groups decreased in MDA content, increased in SOD level, decreased in apoptotic cells and ultrastructure damages, shortened the escaping latency, and increased the frequency of crossing the platform (P<0.001), especially in the high dose group (P<0.05). Conclusion GSPE can relieve the damage of ultrastructure and improve cognition function after obstructive sleep apnea hypoxia in rats.

Key words: sleep apnea, learning, memory, hippocampus, malondialdehyde, superoxide dismutase, apoptosis, rats