Effect of acute exposure to hypobaric hypoxia on learning and memory in adult Sprague-Dawley rats

Zhu, Minxia; Xu, Mengkang; Zhang, Kexin; Li, Juanni; Ma, Hua; Xia, Guanhua; Li, Xuchang; Zhang, Bin; Shi, Honglei

doi:10.1016/j.bbr.2019.03.047

Cited by 14 publications

(11 citation statements)

References 13 publications

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“…In female rats, although CHH exposure had a downward trend in the mRNA expression of NR2B in the hippocampus, it had hardly any effect on the mRNA expression of NR2A. We observed that the relative expressions of NR2A and NR2B were down-regulated in male CHH rats compared to the male control rats, which was similar to the findings of prior studies ( Zhu et al, 2019 ). In light of this, we suggest that there are sex differences involved in the down-regulation of NR2A and NR2B subunits in CHH-exposed animals.…”

Section: Discussionsupporting

confidence: 90%

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

Zhu

Zhang²,

He³

et al. 2022

Front. Neurosci.

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PurposeThis study aims to investigate the role of sex and ovarian hormones in hippocampal damage and cognitive deficits and behavioral dysfunction in rats induced by chronic exposure to hypobaric hypoxia.MethodsSix-week-old male and female SD rats were housed for 3 months either in a real altitude (4,250 m) environment as the model of chronic hypobaric-hypoxia (CHH) or in a plain as controls. The animal behavioral and hippocampal neurons at subcellular, molecular, and ultrastructural levels were characterized after CHH exposure.ResultsAfter 3 months of CHH exposure, (1) male CHH rats’ serum testosterone level was lower than male controls’ whereas female CHH rats’ serum estradiol level was higher than female controls’; (2) Morris water maze test finds that male rats showed more learning and spatial memory deficits than female rats; (3) male rats showed more severe hippocampal damage, hippocampal inflammation, oxidative stress and decreased hippocampal integrity (neurogenesis and dendritic spine density) than female rats; (4) Western blot analysis shows that, compared with the male control group, in male CHH group’s hippocampus, expression of nNOS, HO-1, and Bax protein increased whereas that of Bcl-2 protein decreased; (5) Expression of PON2 protein in male rats (CHH and controls) was lower than female rats (CHH and controls). In addition, CHH exposure decreased the expression of PON2 protein in both male and female rats; (6) qPCR analysis reveals that CHH exposure reduced the gene expression of N-methyl-D-aspartate receptor NR2A and NR2B subunits in male rats’ hippocampus. In addition, compared with the sham CHH group, the expression level of PON2 protein decreased in the OVX-CHH group’s hippocampus whereas oxidative stress, neuroinflammation, and degeneration of hippocampal neurons increased in the OVX-CHH group’s hippocampus.ConclusionAfter CHH exposure, male rats were significantly more likely than female rats to develop hippocampal damage, hippocampal neuroinflammation, and cognitive decline and deficits, suggesting that sex and ovarian hormones were significantly involved in regulating the rats’ susceptibility to CHH exposure-induced hippocampal damage.

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Section: Discussionsupporting

confidence: 90%

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

Zhu

Zhang²,

He³

et al. 2022

Front. Neurosci.

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“…The brain is particularly sensitive to hypoxia-induced injury due to its high oxygen consumption, rich in unsaturated fatty acids and low antioxidant capacity [3]. Increasing evidences have indicated that hypoxia can induce adverse effects on brain [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Norwogonin attenuates hypoxia-induced oxidative stress and apoptosis in PC12 cells

Jing

Gao

Zhang

et al. 2021

BMC Complement Med Ther

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Background Norwogonin is a natural flavone with three phenolic hydroxyl groups in skeletal structure and has excellent antioxidant activity. However, the neuroprotective effect of norwogonin remains unclear. Here, we investigated the protective capacity of norwogonin against oxidative damage elicited by hypoxia in PC12 cells. Methods The cell viability and apoptosis were examined by MTT assay and Annexin V-FITC/PI staining, respectively. Reactive oxygen species (ROS) content was measured using DCFH-DA assay. Lactate dehydrogenase (LDH), malondialdehyde (MDA) and antioxidant enzyme levels were determined using commercial kits. The expression of related genes and proteins was measured by real-time quantitative PCR and Western blotting, respectively. Results We found that norwogonin alleviated hypoxia-induced injury in PC12 cells by increasing the cell viability, reducing LDH release, and ameliorating the changes of cell morphology. Norwogonin also acted as an antioxidant by scavenging ROS, reducing MDA production, maintaining the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and decreasing the expression levels of HIF-1α and VEGF. In addition, norwogonin prevented cell apoptosis via inhibiting the expression levels of caspase-3, cytochrome c and Bax, while increasing the expression levels of Bcl-2 and the ratio of Bcl-2/Bax. Conclusions Norwogonin attenuates hypoxia-induced injury in PC12 cells by quenching ROS, maintaining the activities of antioxidant enzymes, and inhibiting mitochondrial apoptosis pathway.

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“…Studies of spatial, visual, and working memory deficits following hypoxic exposures have been demonstrated using the Morris water maze. Exposure conditions include acute and continuous [38], chronic continuous [39][40][41][42][43], acute intermittent [44], and oscillating, chronic intermittent [45,46]. Hypoxiainduced memory dysfunction has also been demonstrated using a radial-arm maze [47], and an object displacement/replacement test [48] that is similar to the NOR test used in this study.…”

Section: Discussionmentioning

confidence: 84%

Protection of Episodic Memory by Neuroprotective Peptide Treatments in Sprague-Dawley Rats Subjected to Hypoxic Exposure

Chan

2020

AJBSR

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Effect of acute exposure to hypobaric hypoxia on learning and memory in adult Sprague-Dawley rats

Cited by 14 publications

References 13 publications

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

Norwogonin attenuates hypoxia-induced oxidative stress and apoptosis in PC12 cells

Protection of Episodic Memory by Neuroprotective Peptide Treatments in Sprague-Dawley Rats Subjected to Hypoxic Exposure

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