6-姜辣素改善果糖所致中年大鼠骨骼肌异位脂质沉积的研究

6-gingerol ameliorates ectopic lipid accumulation in skeletal muscle of middle-aged rats induced by fructose

目的 探究6-姜辣素改善果糖所致中年大鼠骨骼肌异位脂质沉积的作用及机制。方法 动物实验:将24只15月龄雄性SD大鼠采用随机数字表法分为3组:对照组(CON,正常饮水),模型组(FRU,10%果糖水),6-姜辣素组(GIN,10%果糖水,0.2 mg/kg 6-姜辣素),每组8只,6-姜辣素通过灌胃给药,每日1次,持续49 d。采用酶法检测血浆葡萄糖(GLU)、甘油三酯(TG)及骨骼肌组织TG水平;油红O染色(ORO)检测骨骼肌组织脂质沉积;ELISA检测血浆胰岛素(Insulin);Western blot检测骨骼肌AMPK、p-AMPK、ACC、p-ACC、CPT1A、PPARα及PGC1α蛋白表达。细胞实验:将分化成熟的大鼠骨骼肌细胞分为3组:对照组(CON),模型组(FRU,25 mmol/L果糖),6-姜辣素组(GIN,25 mmol/L果糖,10μmol/L 6-姜辣素),作用24 h。酶法检测细胞内TG水平;ORO检测骨骼肌细胞脂质沉积;Western blot检测骨骼肌细胞AMPK、p-AMPK、ACC、p-ACC及CPT1A蛋白表达。结果 与对照组比较,模型组血浆GLU、TG及Insulin水平明显升高(P<0.05),大鼠骨骼肌组织及骨骼肌细胞内TG含量明显升高(P<0.05),ORO示大鼠骨骼肌组织及骨骼肌细胞内脂质沉积明显,Western blot示p-AMPK/AMPK及p-ACC/ACC降低,CPT1A、PPARα及PGC1α蛋白表达明显降低(P<0.05);与模型组比较,姜辣素组血浆GLU、TG及Insulin水平明显降低(P<0.05),大鼠骨骼肌组织及骨骼肌细胞内TG含量显著降低(P<0.05),ORO示大鼠骨骼肌及骨骼肌细胞内脂质沉积减轻,Western blot示p-AMPK/AMPK及p-ACC/ACC明显升高,CPT1A、PPARα及PGC1α蛋白表达明显升高(P<0.05)。结论 6-姜辣素可改善果糖所致中年大鼠骨骼肌异位脂质沉积,可能与骨骼肌AMPK/ACC/CPT1A通路的激活有关。

Objective To investigate the effect and mechanism of 6-gingerol on improving ectopic lipid accumulation in skeletal muscle of middle-aged rats induced by fructose. Methods A total of 24 male SD rats( 15 months old) were randomly and equally divided into 3 groups: control group( CON,with normal drinking water),model group( FRU,with 10% fructose water) and 6-gingerol group( GIN,with 10%fructose water+0.2 mg/kg 6-gingerol by gavage). Gavage was performed once a day for consecutive 49 days.Levels of plasma glucose( GLU),triglyceride( TG) and skeletal muscle TG were measured by GOD-PAP method;lipid accumulation in skeletal muscle was detected by oil red O staining( ORO);content of plasma insulin was determined by ELISA;protein levels of AMP-activated protein kinase( AMPK),p-AMPK,acetyl-coa carboxylase( ACC),p-ACC,carnitine palmitoyltransferase 1A( CPT1A),peroxisome proliferator activated receptor alpha( PPARα) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha( PGC1α) in skeletal muscle were examined with Western blotting. L6 rat skeletal muscle cells were divided into 3 groups: control group( Con),model group( FRU,treated with 25 mmol/L fructose for 24 h) and6-gingerol group( GIN,treated with 25 mmol/L fructose+10 μmol/L 6-gingerol for 24 h). TG level and lipid accumulation in L6 cells were determined by GOD-PAP and ORO staining,respectively. The expression of AMPK,p-AMPK,ACC,p-ACC and CPT1A was examined by Western blotting. Results As compared with control group,the rat model group had higher levels of plasma GLU,TG and insulin( P<0.05),elevated TG content in both skeletal muscle tissues and cells( P<0.05),as well as notable lipid accumulation in skeletal muscle tissues and cells( P < 0. 05). Western blotting showed that the p-AMPK/AMPK ratio,p-ACC/ACC ratio,and the protein levels of CPT1A,PPARα and PGC1α were all decreased in the model group( P <0.05). However,6-gingerol significantly reduced the levels of plasma GLU,TG and insulin( P < 0. 05),alleviated the TG contents and lipid accumulation in skeletal muscles and cells( P < 0. 05),and greatly increased the p-AMPK/AMPK ratio,p-ACC/ACC ratio and the levels of CPT1A,PPARα and PGC1α in the GIN group( P<0.05). Conclusion 6-gingerol can improve the ectopic lipid accumulation in skeletal muscle of middle-aged rats induced by fructose,which may be related to the activation of AMPK/ACC/CPT1A pathway.