title: Loquat (Eriobotrya japonica) extract prevents dexamethasone-induced muscle atrophy by inhibiting the muscle degradation pathway in Sprague Dawley rats.
abstract: In the Orient, loquat (Eriobotrya japonica) extract (LE) is widely used in teas, food and folk medicines. The leaves of the loquat tree have been used for generations to treat chronic bronchitis, coughs, phlegm production, high fever and gastroenteric disorders. One of the major active components of loquat leaves is ursolic acid, which was recently investigated in the context of preventing muscle atrophy. The present study investigated the therapeutic potential of LE on dexamethasone‑induced muscle atrophy in rats. Daily intraperitoneal injections of dexamethasone caused muscle atrophy and evidence of muscle atrophy prevention by LE was demonstrated using various assays. In particular, dexamethasone‑induced grip strength loss was alleviated by LE and the increase in serum creatine kinase activity, a surrogate marker of muscle damage, caused by dexamethasone injection was reduced by LE. Western blot analysis and immunoprecipitation demonstrated that dexamethasone markedly increased the protein expression levels of muscle ring finger 1 (MuRF1), which causes the ubiquitination and degradation of myosin heavy chain (MyHC), and decreased the protein expression levels of MyHC as well as increased the ubiquitinated MyHC to MyHC ratio. However, LE reduced the dexamethasone‑induced protein expression levels of MuRF1 and ubiquitinated MyHC. Additional experiments revealed that LE supplementation inhibited the nuclear translocation of FoxO1 induced by dexamethasone. These findings suggested that LE prevented dexamethasone‑induced muscle atrophy by regulating the FoxO1 transcription factor and subsequently the expression of MuRF1.
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Kyung Kyun
authors.initials: KK
authors.lastname: Noh
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Ki Wung
authors.initials: KW
authors.lastname: Chung
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Bokyung
authors.initials: B
authors.lastname: Sung
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Min Jo
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Chan Hum
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Changshin
authors.initials: C
authors.lastname: Yoon
authors.affiliation: Department of Food Science and Nutrition, Pukyong National University, Busan 608‑737, Republic of Korea.
authors.forename: Jae Sue
authors.initials: JS
authors.lastname: Choi
authors.affiliation: Longevity Life Science and Technology Institute, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Mi Kyung
authors.initials: MK
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, Pusan National University School of Medicine, Yangsan, Gyeongsangnam‑do 626‑770, Republic of Korea.
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Kim
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Nam Deuk
authors.initials: ND
authors.lastname: Kim
authors.affiliation: Department of Pharmacy, Molecular Inflammation Research Center for Aging Intervention, Pusan National University, Busan 609‑735, Republic of Korea.
authors.forename: Hae Young
authors.initials: HY
authors.lastname: Chung
mesh_terms: D000818:Animals; D003907:Dexamethasone; D031983:Eriobotrya / Q000737:chemistry*; D051858:Forkhead Transcription Factors / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000627:therapeutic use*; D059748:Proteolysis / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D000070584:Tripartite Motif Proteins; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D000071161:Forkhead Box Protein O1
chemical_list: D003907:Dexamethasone; D051858:Forkhead Transcription Factors; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D010936:Plant Extracts; D000070584:Tripartite Motif Proteins; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases; C074639:Foxo1 protein, rat; D000071161:Forkhead Box Protein O1; C499086:Trim63 protein, rat