Anti-Hypoxic Molecular Mechanisms of Rhodiola crenulata Extract in Zebrafish as Revealed by Metabonomics

Yi Ma,Pingxiang Xu,Xuelin Zhou,Ming Xue,Xiaorong Li,Yi Wu,Zhengchao Xia,Jingyi Li

doi:10.3389/fphar.2019.01356

Abstract

The health supplement of Rhodiola crenulata (RC) is well known for its effective properties against hypoxia. However, the mechanisms of its anti-hypoxic action were still unclear. The objective of this work was to evaluate the molecular mechanisms of RC extract against hypoxia in a hypoxic zebrafish model through metabonomics and network pharmacology analysis. The hypoxic zebrafish model in the environment with low concentration (3%) of oxygen was constructed and used to explore the anti-hypoxic effects of RC extract, followed by detecting the changes of the metabolome in the brain through liquid chromatography–high resolution mass spectrometry. An in silico network for metabolite-protein interactions was further established to examine the potential mechanisms of RC extract, and the mRNA expression levels of the key nodes were validated by real-time quantitative PCR. As results, RC extract could keep zebrafish survive after 72-h hypoxia via improving lactate dehydrogenase, citrate synthase, and hypoxia-induced factor-1α in brains. One hundred and forty-two differential metabolites were screened in the metabonomics, and sphingolipid metabolism pathway was significantly regulated after RC treatment. The constructed protein-metabolites network indicated that the HIF-related signals were recovered, and the mRNA level of AMPK was elevated. In conclusion, RC extract had markedly anti-hypoxic effects in zebrafish via changing sphingolipid metabolism, HIF-related and AMPK signaling pathways.

Highlights

Oxygen homeostasis is a survival prerequisite for most of the living creatures on the earth
The activities of lactate dehydrogenase (LDH) and hypoxia-induced factor-1α (HIF-1α) were significantly declined in the Rhodiola crenulata (RC) group, when compared to those in the hypoxia group (Figure 2)
Our results indicated that RC extract could decrease LDH activities and HIF-1α expression which were elevated under hypoxia

Summary

Introduction

Oxygen homeostasis is a survival prerequisite for most of the living creatures on the earth. Oxygen participates in the oxidation reaction for contributing necessary biology processing, and a suitable concentration of oxygen may drive carbon metabolism for energy production. Some important pathways may be disturbed which could induce organ damage (Chaillou, 2018). As a reduced oxygen environment, can induce the changes of physiology and Abbreviations: RC, Rhodiola crenulata; LDH, citrate synthase; HIF-1α, hypoxia-induced factor-1α. Anti-Hypoxic Mechanisms of Rhodiola crenulata Extract pathology in the body. People existing at high altitude are damaged by hypoxia environment, and organ ischemia with low oxygen supply can impair their health (Hiraga, 2018)

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