摘要
目的探讨Wnt7a-Akt/m TOR信号通路在肾衰营养胶囊改善慢性肾衰竭(CRF)大鼠骨骼肌萎缩中的作用及机制。方法采用切除5/6肾的方法制作CRF模型,予4%酪蛋白饲料喂养制作CRF营养不良大鼠模型。将大鼠随机分为正常组、模型组、中药组和开同组。采用组织病理学检测TA横截面积并计算肌纤维面积分布;采用同位素14+C-苯丙氨酸掺入法检测肌肉蛋白合成;采用Western blot检测Wnt7a-Akt/m TOR信号通路中的蛋白表达。结果肾衰营养胶囊增加了CRF大鼠体质量和骨骼肌质量的作用,形态学表现为TA横截面积增加,促进蛋白质合成增加以及骨骼肌组织Wnt7a-Akt/m TOR信号通路中蛋白表达上调。结论肾衰营养胶囊具有改善CRF模型大鼠骨骼肌萎缩的作用,其机制可能上调骨骼肌Wnt7a-Akt/m TOR信号通路和促进骨骼肌蛋白质合成相关。
Objective To observe the effect of Shenshuai Yingyang Capsule(SSYYJN) in ameliorating muscle atrophy in rats with chronic renal failure(CRF) and explore the role of Wnt7a- Akt/m TOR signal pathway in mediating this effect. Methods Male rats were randomly assigned to 5/6 nephrectomy group and sham- operated group, and the former group was further randomly divided into CRF model group, KA group, and SSYYJN group. The size of anterior tibia muscle was examined microscopically with HE staining. Protein synthesis in the soleus muscle was investigated by14C- phenylalanine experiment,and the expression of Wnt7 a, frizzled- 7, phospho- Akt, phospho- m TOR and GAPDH were detected with Western blotting.Results The body weight, the wet and dry weight, cross- sectional area, and muscle protein synthesis of the anterior tibia muscles, and expressions of the proteins in the Wnt7a/Akt signaling pathway all increased significantly in SSYYJN and KA groups as compared with those in the model group. Conclusion SSYYJN can effectively improve muscle atrophy in the rat model of CRF possibly by reversing the reduction in the expressions of Wnt7a/Akt signaling pathway proteins in the skeletal muscles.
引文
[1]Bonanni A,Mannucci I,Verzola D,et al.Protein-Energy wasting and mortality in chronic kidney disease[J].Int J Environ Res Public Health,2011,8(5):1631-54.
[2]Jadeja YP,Kher V.Protein energy wasting in chronic kidney disease:An update with focus on nutritional interventions to improve outcomes[J].Indian J Endocrinol Metab,2012,16(2):246-51.
[3]Attaix D,Baracos VE,Pichard C.Muscle wasting:a crosstalk between protein synthesis and breakdown signalling[J].Curr Opin Clin Nutr Metab Care,2012,15(3):209-10.
[4]Cao PR,Kim HJ,Lecker SH.Ubiquitin-protein ligases in muscle wasting[J].Int J Biochem Cell Biol,2005,37(10):2088-97.
[5]Wang XH,Mitch WE.Mechanisms of muscle wasting in chronic kidney disease[J].Nat Rev Nephrol,2014,10(9):504-16.
[6]Workeneh BT,Mitch WE.Review of muscle wasting associated with chronic kidney disease[J].Am J Clin Nutr,2010,91(4):1128S-32S.
[7]Cisternas P,Henriquez JP,Brandan EA.Wnt signaling in skeletal muscle dynamics:myogenesis,neuromuscular synapse and fibrosis[J].Mol Neurobiol,2014,49(1):574-89.
[8]von Maltzahn J,Zinoviev R,Chang NC,et al.A truncated Wnt7a retains full biological activity in skeletal muscle[J].Nat Commun,2013,4:2869.
[9]Bentzinger CF,von Maltzahn J,Dumont NA,et al.Wnt7a stimulates myogenic stem cell motility and engraftment resulting in improved muscle strength[J].J Cell Biol,2014,205(1):97-111.
[10]唐春苑,叶晓青,王饶萍.维持性血液透析患者营养状况与睡眠关系研究[J].护理学报,2013(13):18-21.
[11]魏连波,张颖,汪南海.肾衰养真颗粒治疗慢性肾脏病4、5期并发营养不良的临床观察[J].中国中西医结合肾病杂志,2009,10(8):696-9.
[12]魏连波,邓聪,陈杰彬,等.肾衰养真胶囊对5/6肾切除慢性肾衰营养不良大鼠营养状态的影响[J].中药材,2008,31(9):1391-5.
[13]Le Grand F,Jones AE,Seale V,et al.Wnt7a activates the planar cell polarity pathway to drive the symmetric expansion of satellite stem cells[J].Cell Stem Cell,2009,4(6):535-47.
[14]Gingras AC,Raught B,Sonenberg N.Regulation of translation initiation by FRAP/m TOR[J].Genes Dev,2001,15(07):807-26.
[15]Jefferies HB,Fumagalli S,Dennis PB,et al.Rapamycin suppresses5'TOP m RNA translation through inhibition of p70s6k[J].EMBO J,1997,16(12):3693-704.
[16]Lu L,Wang DT,Shi Y,et al.Astragalus polysaccharide improves muscle atrophy from dexamethasone-and peroxide-induced injury in vitro[J].Int J Biol Macromol,2013,61(5):7-16.
[17]Shi Y,Wang DT,Lu L,et al.Ligustilide prevents the apoptosis effects of tumour necrosis factor-alpha during C2C12 cell differentiation[J].Int Immunopharmacol,2014,19(2):358-64.