Angelica Sinensis promotes myotube hypertrophy through the PI3K/Akt/mTOR pathway.

Tzu-Shao Yeh,Mei-Chich Hsu,Jen-Fang Liu,Suh-Ching Yang,Cheng-Chen Hsu

doi:10.1186/1472-6882-14-144

Abstract

BackgroundAngelica Sinensis (AS), a folk medicine, has long been used in ergogenic aids for athletes, but there is little scientific evidence supporting its effects. We investigated whether AS induces hypertrophy in myotubes through the phosphatidylinositol 3-kinase (PI3K)/Akt (also termed PKB)/mammalian target of the rapamycin (mTOR) pathway.MethodsAn in vitro experiment investigating the induction of hypertrophy in myotubes was conducted. To investigate whether AS promoted the hypertrophy of myotubes, an established in vitro model of myotube hypertrophy with and without AS was used and examined using microscopic images. The role of the PI3K/Akt/mTOR signaling pathway in AS-induced myotube hypertrophy was evaluated. Two inhibitors, wortmannin (an inhibitor of PI3K) and rapamycin (an inhibitor of mTOR), were used.ResultThe results revealed that the myotube diameters in the AS-treated group were significantly larger than those in the untreated control group (P < 0.05). Wortmannin and rapamycin inhibited AS-induced hypertrophy. Furthermore, AS increased Akt and mTOR phosphorylation through the PI3K pathway and induced myotube hypertrophy.ConclusionThe results confirmed that AS induces hypertrophy in myotubes through the PI3K/Akt/mTOR pathway.

Highlights

Angelica Sinensis (AS), a folk medicine, has long been used in ergogenic aids for athletes, but there is little scientific evidence supporting its effects
The results confirmed that AS induces hypertrophy in myotubes through the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of the rapamycin (mTOR) pathway
The stocks were diluted in the medium and added directly to the cultured cells according to the following final concentrations: AS (1, 10, 102, 103, 104, 105, 106 ng/mL in 2% horse serum (HS)/Dulbecco’s modified Eagle’s medium (DMEM)), wortmannin (100 nM in DMEM), rapamycin (10 ng/mL in DMEM), and insulin-like growth factor 1 (IGF-1) (10 ng/mL in 2% HS/DMEM; as a positive control for the activated PI3K/Akt/mTOR pathway)

Summary

Introduction

Angelica Sinensis (AS), a folk medicine, has long been used in ergogenic aids for athletes, but there is little scientific evidence supporting its effects. We investigated whether AS induces hypertrophy in myotubes through the phosphatidylinositol 3-kinase (PI3K)/Akt ( termed PKB)/mammalian target of the rapamycin (mTOR) pathway. The phosphatidylinositol 3-kinase (PI3K)/ Akt ( termed PKB)/mammalian target of rapamycin (mTOR) pathway is recognized as a possible mechanism that regulates muscle mass [4,5,6]. Skeletal muscle hypertrophy occurs as a result of an increased size, instead of increased number, of preexisting skeletal muscle fibers [7,8]. The effects of this pathway on skeletal muscle are exhibited most prominently downstream of insulin-like growth factor 1 (IGF-1) signaling. Akt is a serine-threonine protein kinase that can inhibit

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Results

Conclusion