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Effects of intermittent hypoxia stimulation with different frequencies on HT22 cell viability and expression of Hif-1α and p-NF-κB

YANG Sheng-Chang, ZHAO Yang, ZHENG Yu-Ying, LI Wen-Ya, ZHAO Ming, JI En-Sheng^*

Department of Physiology, Hebei University of Chinese Medicine, Shijiazhuang 050200, China

Abstract

Intermittent hypoxia (IH) could induce cognitive impairment through oxidative stress and inflammation. However, the degree of cell damage is closely related to the IH stimulus frequency. IH stimulation with different frequencies also induces opposite results on neuronal cell lines. Therefore, this study was aimed to compare the effects of IH stimulation with three different frequencies on murine hippocampal neuronal HT22 cell activity, and to explore the molecular mechanism of the IH stimulus frequency-related neuron injury. HT22 cells were cultured and divided into control group and three IH stimulation groups with different frequencies. Oxygen concentration in the chamber was circulated between 21% and 1% (IH1 group, 6 cycles/h; IH2 group, 2 cycles/h; IH3 group, 0.6 cycle/h). Cell morphology was observed at 6, 12, 24 and 48 h of IH treatment. Cell viability was determined by the CCK-8 kit, lactate dehydrogenase (LDH) content in cell supernatant was determined by LDH kit, oxidative stress level was detected by the reactive oxygen species (ROS) probe, and protein expression levels of hypoxia inducible factor-1α (Hif-1α) and phosphorylated nuclear factor κB (p-NF-κB) were detected by Western blot. The results showed that, compared with control group, cell number and activity in the three IH groups were decreased, LDH content and ROS levels were increased with the prolongation of IH stimulation time, and the changes were most obvious in the IH1 group among those of the three IH groups. Hif-1α expression and the p-NF-κB/NF-κB ratio were also up-regulated with the prolongation of IH stimulation time, and the changes of IH1 group were the most significant. These results suggest that IH stimulation induces oxidative stress injury in HT22 cells, which is related to increased Hif-1α expression and NF-κB phosphorylation. Moreover, the higher frequency of IH stimulation induces more serious cell injury.

Key words: intermittent hypoxia; oxidative stress; cell activity; hypoxia inducible factor-1α; nuclear factor κB

Received: 2020-03-08　　Accepted: 2020-07-15

Corresponding author: 吉恩生　　E-mail: jesphy@126.com

DOI: 10.13294/j.aps.2021.0003

Citing This Article：

YANG Sheng-Chang, ZHAO Yang, ZHENG Yu-Ying, LI Wen-Ya, ZHAO Ming, JI En-Sheng. Effects of intermittent hypoxia stimulation with different frequencies on HT22 cell viability and expression of Hif-1α and p-NF-κB. Acta Physiol Sin 2021; 73 (1): 26-34 (in Chinese with English abstract).