Objective: To establish an intermittent hypoxia (IH) animal model by simulating the features of obstructive sleep apnea-hypopnea syndrome and observe the expressions of hypoxia-inducible factor-1 (HIF-1) and survivin and the occurrence of apoptosis in the hippocampal CA1 neuron of rats with early IH.
Methods: Male Wistar rats (n=72) were randomly divided into control group and IH group. In control group, rats were given compressed air and in IH group, rats were exposed to 50 mL/L IH for 7 hours a day, lasting 3, 7, 14 and 21 days, respectively. The expressions of HIF-1 and survivin in hippocampal CA1 were detected by immunohistochemistry and the neuronal apoptosis index was calculated by TUNEL.
Results: Compared with control group, apoptosis index in the third day of 5% IH group had no significant difference, while apoptosis index in IH 7-, 14- and 21-day groups were significantly higher than that in control group, and on the 21st day it reached a peak. The expressions of HIF-1 and survivin protein in 5% IH group significantly increased as compared with control group at each time point, and they peaked on the 14th day, then decreased gradually. There was a positive relationship between the expressions of HIF-1 and survivin.
Conclusion: Early IH can induce HIF-1 and survivin protein expressions in rat hippocampal CA1, and their expressions may play an important role in the regulation of neuronal apoptosis.