草莓葉乙醇萃取物對調控脂多醣誘發C57BL/6J小鼠發炎反應及肌肉耗損之功效

Effect of the strawberry leaf ethanol extract on lipopolysaccharide-induced inflammatory response and muscle wasting in C57BL/6J mice

顏玉佩(Yu-Pei, Yen)

指導教授 ： 劉德中

中山醫學大學/健康管理學院/營養學研究所/碩士(2016年)

摘要

脂多醣(Lipopolysaccharide, LPS)為革蘭氏陰性菌細胞壁的主要成分，先前研究證實，LPS會誘發小鼠生成大量促發炎媒介物，導致體內器官發炎，亦會活化泛素‐蛋白酶體途徑(ubiquitin-proteasome pathway, UPP)、自噬‐溶酶體途徑(autophagy-lysosome pathway, ALP)及Caspase-3，增加骨骼肌蛋白質分解，使肌肉萎縮。文獻指出，草莓葉萃取物可抑制發炎、增加抗氧化酵素及降低脂質過氧化，而本研究將探討草莓葉乙醇萃取物是否能抑制LPS誘發的發炎反應及肌肉萎縮。C57BL/6J小鼠灌食滅菌水或草莓葉乙醇萃取物 (500 mg/kg)，每週3次，持續2週後，在小鼠腹腔內注射LPS，18小時後犧牲。研究結果顯示，草莓葉乙醇萃取物可以改善LPS造成脾臟腫大，降低血液、肝、脾、肺臟及副睪脂肪促發炎媒介物tumor necrosis factor-alpha、interleukin-6、interleukin-1 beta、monocyte chemoattractant protein-1、inducible nitric oxide synthase、cytochrome c oxidase-2生成，並減少紅血球glutathione耗損、紅血球及肝臟malondialdehyde的生成，同時降低肝臟nuclear factor erythroid 2-related factor 2的表現。灌食草莓葉乙醇萃取物可顯著改善LPS誘發脛前肌 myosin heavy chain蛋白質及脛前肌重量的減少。灌食草莓葉乙醇萃取物亦可減少LPS誘發UPP路徑中 muscle atrophy F-box與muscle RING finger protein 1表現及Caspase-3活性。此外，草莓葉乙醇萃取物處理可減少LPS誘發肌肉組織inhibitor kappa B-α、inhibitor kappa B kinaseα/β、mitogen-activated protein kinases (MAPKs)的磷酸化及NF-κB p65、forkhead box protein O 1核蛋白的表現量。綜合以上實驗結果可知，補充草莓葉乙醇萃取物可經由抑制MAPKs、NF-κB和FoxO1活化，顯著改善LPS誘發的發炎反應，減少蛋白質分解相關分子的表現，改善LPS誘發之骨骼肌肉耗損。

關鍵字

草莓葉 ； 脂多醣(LPS) ； UPP路徑 ； 肌肉耗損 ； 促發炎細胞因子

並列摘要

Lipopolysaccharide (LPS), a main component of the cell wall of Gram-negative bacteria, could increase pro-inflammatory mediator production which result in organ inflammation. Data have shown that LPS through activation of ubiquitin-proteasome pathway (UPP), autophagy-lysosome pathway, Caspase-3, causes skeletal muscle protein degradation and then muscle atrophy. Strawberry leaf extracts can suppress inflammation and lipid peroxidation as well as increase antioxidant enzyme expression. The aim of this study was to investigate the inhibitory effect of strawberry leaf ethanol extract on LPS-induced inflammatory response and muscle atrophy. C57BL/6J mice were given dd water or strawberry leaf ethanol extract (500 mg/kg, 150 μl/mouse by intragastric gavage, every other day), three times a week for two weeks, then sacrificed after intraperitoneal injection of LPS eighteen hours. Strawberry leaf ethanol extract can significantly decrease LPS-induced spleen enlargement as well as pro-inflammatory mediator tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, monocyte chemoattractant protein-1, inducible nitric oxide synthase, cytochrome c oxidase-2 production in plasma, liver, spleen, lung and epididymis adipose tissue, glutathione depletion and malondialdehyde (MDA) production in RBC as well as MDA production and nuclear factor erythroid 2-related factor 2 reduction. Notably, supplementation with strawberry leaf ethanol extract could decrease LPS-induced depletion of myosin heavy chain expression and tibialis anterior muscle weight. Strawberry leaf ethanol extract significantly decreased LPS-induced expression of UPP related protein, muscle F-box 1, muscle RING finger protein 1, and caspase-3 activity that result in decrease of protein degradation and muscle atrophy in LPS treated mice. Moreover, strawberry leaf ethanol extract significantly diminished LPS-induced phosphorylation of inhibitor kappa B, inhibitor kappa B kinase, mitogen-activated protein kinases (MAPKs) as well as NF-kB p65 and forkhead box protein O 1 nuclear protein expression. In summary, supplementation of strawberry leaf ethanol extract significantly lessened LPS-induced inflammation and muscle atrophy which is related to its inhibitory effect on LPS-induced activation of MAPKs, NF-kB and FoxO1 as well as protein degradation pathways.

並列關鍵字

strawberry leaves ； lipopolysaccharide ； ubiquitin-proteasome pathway ； muscle atrophy ； pro-inflammatory cytokines

參考文獻

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