Effect of aqueous extract of Astragalus membranaceus on behavioral cognition of rats living at high altitude

doi:10.19852/j.cnki.jtcm.2022.01.005

Abstract

Abstract:

OBJECTIVE: To investigate the effect of aqueous extract of Astragalus membranaceus on cognitive ability of rats living at high altitude.

METHODS: Rats were exposed to a simulated high-altitude hypobaric hypoxia chamber. The behavior of rats was tested by eight-arm maze. The contents of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS) and activity of total superoxide dismutase (T-SOD) in hippocampus were measured. The expressions of mammalian target of rapamycin (mTOR) and cleaved capase-3 in hippocampus were determined by reverse transcription-polymerase chain reaction and Western blot.

RESULTS: The behavioral cognitive ability of the hypoxic control group was significantly lower than that of the normoxic control group. Under hypoxic environment, after the administration of aqueous extract of Astragalus membranaceus, the behavioral cognitive ability of rats was significantly improved. In hippocampal tissue, the content of MDA and ROS were significantly decreased, while the content of GSH and activity of T-SOD in hippocampus were significantly increased. The mRNA expression of mTOR and P70S6K and the protein expression of p-mTOR were significantly increased; the mRNA expression of 4E-binding protein 1 (4E-BP1) and the protein expression of phosphorylated-4E-BP1 (p-4E-BP1) and cleaved capase-3 were significantly decreased.

CONCLUSION: When the rats are exposed to high altitude hypoxia, the behavioral cognitive ability could be significantly reduced. Aqueous extract of Astragalus membranaceus can significantly improve cognitive function in rats under hypoxia. The potential mechanism is related to improving oxidative stress, reducing the accumulation of free radicals and metabolites, and activating mTOR signaling pathway.

Key words: hypoxia, cognition, Astragalus propinquus, oxidative stress, TOR serine-threonine kinases

Xing DU, Tianlong LIU, Wendi TAO, Maoxing LI, Xiaolin LI, Lan YAN. Effect of aqueous extract of Astragalus membranaceus on behavioral cognition of rats living at high altitude[J]. Journal of Traditional Chinese Medicine, 2022, 42(1): 58-64.

Figures/Tables 8

Table 1 GAPDH, m-TOR, P70S6K and 4E-BP1 primer sequences

Primer name	Base sequence
GAPDH	Upstream: 5'-GGCACAGTCAAGGCTGAGAATG-3'
GAPDH	Downstream: 5'-ATGGTGGTGAAGACGCCAGTA-3'
m-TOR	Upstream: 5'-CGTGCTGTTGGGTGAGAGAG-3'
m-TOR	Downstream: 5'-TTCGTGTCCATCTTCTTGTCG-3'
P70S6K	Upstream: 5'-GCCTCCCTACCTCACACAAGA-3'
P70S6K	Downstream: 5'-CCACCTTCCGAGCCAAAA-3'
4E-BP1	Upstream: 5'-GGAGAGCCACAGCAGTCAGG-3'
4E-BP1	Downstream: 5'-TCAACAGAGGCACAAGGAGGTAT-3'

Table 2 Results of the eight-arm maze experimental ($\bar{x}$ ± s)

Group	Dose	n	WME (times)	RME (times)	TE (times)	TT (s)
NCG	0.1 mL/10 g	10	0.5±0.4	0.5±0.5	1.0±0.6	112.1±31.0
HCG	0.1 mL/10 g	10	1.8±1.0^b	3.2±1.2^b	5.0±1.3^b	224.2±42.9^b
PG	0.35 g/kg	10	1.3±1.0^a	1.8±0.8^bd	3.1±1.9^b	154.5±57.6^d
H-AMG	0.35 g/kg	10	1.4±0.6^a	1.9±0.8^bc	3.2±0.7^bd	133.3±47.5^d
M-AMG	0.15 g/kg	10	1.2±0.7^a	1.9±0.8^bc	3.1±1.0^bd	152.1±49.0^d
L-AMG	0.05 g/kg	10	1.3±0.9^a	2.2±0.9^bc	3.5±1.2^bc	174.3±50.9^bc

Figure 1 Pathological damages in hippocampus of each group of rats (n = 8, ×100) A: NCG: normoxic control group; B: HCG: hypoxia control group; C: PG: positive group (1.35 g/kg L-leucine); D: H-AMG: high dose group (0.35 g/kg Astragalus membranaceus); E: M-AMG: middle dose group (0.15 g/kg Astragalus membranaceus); F: L-AMG: low dose group (0.05 g/kg Astragalus membranaceus). Rats were administered by gavage once a day for 7 d.

Table 3 Contents of MDA and GSH in hippocampus of each group of rats ($\bar{x}$ ± s)

Group	Dose	n	MDA (nmol/mgprot)	GSH (mg/gprot)
NCG	0.1 mL/10 g	8	1.6±0.3	21.3±2.7
HCG	0.1 mL/10 g	8	2.8±0.5^a	16.6±1.0^a
PG	0.35 g/kg	8	1.7±0.5^b	19.4±2.5^d
H-AMG	0.35 g/kg	8	1.8±0.6^b	19.1±2.6^d
M-AMG	0.15 g/kg	8	1.9±0.4^b	19.0±2.3^d
L-AMG	0.05 g/kg	8	2.0±0.4^bc	17.6±2.6^cd

Table 4 T-SOD activity and ROS content in hippocampus of each group of rats ($\bar{x}$ ± s)

Group	Dose	n	T-SOD (U/mgprot)	ROS (FU/mgprot)
NCG	0.1 mL/10 g	8	303.2±34.7	1.4±0.3 (10⁷)
HCG	0.1 mL/10 g	8	244.3±39.1^a	2.0±0.3^a (10⁷)
PG	0.35 g/kg	8	286.0±34.0^b	1.4±0.2^c (10⁷)
H-AMG	0.35 g/kg	8	285.0±25.0^b	1.5±0.2^c (10⁷)
M-AMG	0.15 g/kg	8	280.4±26.6^b	1.6±0.3^c (10⁷)
L-AMG	0.05 g/kg	8	249.6 ±19.2^a	1.8±0.3^d (10⁷)

Table 5 Effect of aqueous extract of Astragalus membranaceus on target gene expression ($\bar{x}$ ± s)

Group	Dose	n	mTOR mRNA	P70S6K mRNA	4E-BP1 mRNA
NCG	0.1 mL/10 g	8	1.0±0.1	1.0±0.1	1.0±0.0
HCG	0.1 mL/10 g	8	0.5±0.1^a	0.7±0.1^a	1.5±0.2^d
PG	0.35 g/kg	8	0.9±0.1^b	1.0±0.1^b	0.8±0.1^c
H-AMG	0.35 g/kg	8	0.9±0.2^b	0.9±0.2^c	0.8±0.1^c
M-AMG	0.15 g/kg	8	0.9±0.1^b	0.8±0.1	0.9±0.1^c
L-AMG	0.05 g/kg	8	0.7±0.1^c	0.8±0.1	1.26± 0.3

Figure 2 Effect of aqueous extract of Astragalus membranaceus on target gene expression ($\bar{x}$± s, n = 3) A: Western blot banding of protein expression; B: quantitative analysis of p-mTOR; C: quantitative analysis of p-P70S6K; D: quantitative analysis of p-4E-BP1. NCG: normoxic control group; HCG: hypoxia control group; PG: positive group (1.35 g/kg L-leucine); H-AMG: high dose group (0.35 g/kg Astragalus membranaceus); M-AMG: middle dose group (0.15 g/kg Astragalus membranaceus); L-AMG: low dose group (0.05 g/kg Astragalus membranaceus). Rats were administered by gavage once a day for 7 d. mTOR: mammalian target of rapamycin; 4E-BP1: 4E-binding protein 1. Compared with NCG, aP < 0.01; compared with HCG group, bP < 0.05, cP < 0.01.

Figure 3 Effect of aqueous extract of Astragalus membranaceus on cleaved capase-3 protein expression ($\bar{x}$ ± s, n = 3) A: Western blot banding of protein expression; B: quantitative analysis of cleaved capase-3. NCG: normoxic control group; HCG: hypoxia control group; PG: positive group (1.35 g/kg L-leucine); H-AMG: high dose group (0.35 g/kg Astragalus membranaceus); M-AMG: middle dose group (0.15 g/kg Astragalus membranaceus); L-AMG: low dose group (0.05 g/kg Astragalus membranaceus). Rats were administered by gavage once a day for 7 d. Compared with NCG, aP < 0.05; compared with HCG group, bP < 0.01, cP < 0.05.

References 29

[1]	Zhao J, Zhang R, Yu Q, et al. Characteristics of EEG activity during high altitude hypoxia and lowland reoxygenation. Brain Res 2016;1648:243-9.
[2]	Wei D, Wei L, Li X, et al. Effect of hypoxia on Ldh-c expression in somatic cells of plateau pika. Int J Env Res Pub He 2016;13:773.
[3]	Vargas M, Becerril-Ángeles M, Medina-Reyes I, et al. Altitude above 1500 m is a major determinant of asthma incidence. An ecological study. Resp Med 2018;135:1-7.
[4]	Luks A, Auerbach P, Freer L, et al. Wilderness medical society clinical practice guidelines for the prevention and treatment of acute altitude illness: 2019 update. Wild Environ Med 2019;30:S3-S18.
[5]	Bärtsch P, Swenson E. Acute high-altitude illnesses. NEJM 2013;368:2294-302.
[6]	Asmaro D, Mayall J, Ferguson S. Cognition at altitude: impairment in executive and memory processes under hypoxic conditions. Aviat Space Environ Med 2013;84:1159-65.
[7]	Yan X. Cognitive impairments at high altitudes and adaptation. High Alt Med Biol 2014;15:141-5.
[8]	Wilson M, Newman S, Imray C. The cerebral effects of ascent to high altitudes. Lancet Neurol 2009;8:175-91.
[9]	Movafeghi A, Djozan D, Razeghi J, et al. Identification of volatile organic compounds in leaves, roots and gum of Astragalus compactus Lam. using solid phase microextraction followed by GC-MS analysis. Nat Prod Res 2010;24:703-9.
[10]	Auyeung KK, Han Q, Ko JK. Astragalus membranaceus: a review of its protection against inflammation and gastrointestinal cancers. Am J Chin Med 2016;44:1-22.
[11]	Li X, Qu L, Dong Y, et al. A review of recent research progress on the astragalus genus. Molecules 2014;19:18850-80.
[12]	Wang Y, Liu L, Ma Y, et al. Chemical discrimination of astragalus mongholicus and astragalus membranaceus based on metabolomics using UHPLC-ESI-Q-TOF-MS/MS approach. molecules 2019;24:4064.
[13]	Liu M, Wu K, Mao X, et al. Astragalus polysaccharide improves insulin sensitivity in KKAy mice: regulation of PKB/GLUT4 signaling in skeletal muscle. J Ethnopharmacol 2010;127:32-37.
[14]	Du X, Chen X, Zhao B, et al. Astragalus polysaccharides enhance the humoral and cellular immune responses of hepatitis B surface antigen vaccination through inhibiting the expression of transforming growth factor β and the frequency of regulatory T cells. FEMS Immunol Med Microbiol 2011;63:228-35.
[15]	Nalbantsoy A, Nesil T, Erden S, et al. Adjuvant effects of Astragalus saponins macrophyllosaponin B and astragaloside VII. J Ethnopharmacol 2011;134:897-903.
[16]	Linnek J, Mitaine-Offer A, Miyamoto T, et al. Cycloartane-type glycosides from two species of Astragalus (Fabaceae). Nat Prod Commun 2009;4:477-78.
[17]	Li M, Zhu Y, Li J, et al. Effect and mechanism of verbascoside on hypoxic memory injury in plateau. Phytother Res 2019;33:2692-701.
[18]	Xu H, Baracskay P, O'Neill J, et al. Assembly responses of hippocampal CA1 place cells predict learned behavior in goal-directed spatial tasks on the radial eight-arm maze. Neuron 2019;101:119-32.
[19]	Sharma V, Das S, Dhar P, et al. Domain specific changes in cognition at high altitude and its correlation with hyperhomocysteinemia. Plos One 2014;9:e101448.
[20]	Rimoldi S, Rexhaj E, Duplain H, et al. Acute and chronic altitude-induced cognitive dysfunction in children and adolescents. J Pediatr 2016;169:238-43.
[21]	Zhou B, Li M, Cao X, et al. Phenylethanoid glycosides of Pedicularis muscicola Maxim ameliorate high altitude-induced memory impairment. Physiol Behav 2016;157:39-46.
[22]	Zhang G, Zhou S, Yuan C, et al. The effects of short-term and long-term exposure to a high altitude hypoxic environment on neurobehavioral function. High Alt Med Biol 2013;14:338-41.
[23]	Joyce K, Lucas S, Imray C, et al. Advances in the available non-biological pharmacotherapy prevention and treatment of acute mountain sickness and high altitude cerebral and pulmonary oedema. Expert Opin Pharmaco 2018;19:1891-902.
[24]	Davranche K, Casini L, Arnal P, et al. Cognitive functions and cerebral oxygenation changes during acute and prolonged hypoxic exposure. Physiol Behav 2016;164:189-97.
[25]	Ma H, Li X, Liu M, et al. Mental Rotation Effect on Adult Immigrants with Long-term Exposure to High Altitude in Tibet: An ERP Study. Neuroscience 2018;386:339-50.
[26]	Fuhrmann D, Brüne B. Mitochondrial composition and function under the control of hypoxia. Redox Biol 2017;12:208-15.
[27]	Zeng H. mTOR signaling in immune cells and its implications for cancer immunotherapy. Cancer Lett 2017;408:182-89.
[28]	Woillard J, Kamar N, Rousseau A, et al. Association of sirolimus adverse effects with mTOR, p70S6K or Raptor polymorphisms in kidney transplant recipients. Pharmacogenet Genomics 2012;22:725-32.
[29]	Fu S, Imai K, Sawasaki T, et al. ScreenCap3: Improving prediction of caspase-3 cleavage sites using experimentally verified noncleavage sites. Proteomics 2014;14:2042-6.

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