摘要
目的观察不同月龄大鼠腓肠肌的湿重体重比、腓肠肌的微观组织形态、衰老相关指标超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量、生肌调节因子〔成肌生化因子(MyoD)、肌肉卫星细胞(Myogenin)〕随月龄的变化情况,评价不同月龄SD大鼠骨骼肌形态学及相关蛋白的表达情况,为自然衰老SD大鼠骨骼肌萎缩模型的研究提供参考。方法将56只正常的雄性SD大鼠随机分为6月龄组、8月龄组、12月龄组、14月龄组、16月龄组、18月龄组、20月龄组,自然饮食,于对应月龄时取双侧腓肠肌和血液,腓肠肌称重后计算湿重体重比,血液离心分离后检测肌肉和血清中SOD和MDA的含量,肌肉中MyoD、Myogenin的表达。结果14月龄以后,随着大鼠衰老,死亡率逐渐升高。从形态学上看,较6月龄相比,8月龄大鼠腓肠肌并无明显萎缩,12月龄后腓肠肌出现明显萎缩,骨骼肌细胞出现轻度退行性变化,随着月龄增加,腓肠肌萎缩和肌纤维衰老坏死越明显,提示12月龄后大鼠腓肠肌出现明显萎缩和退行性变化,可以满足造模要求。12月龄大鼠腓肠肌和血清中的SOD活力较8月龄无显著差异(P>0.05),到14月龄时才明显下降,而且随着月龄增加,SOD活力下降越明显(均P<0.05);血清及腓肠肌中MDA含量12月龄升高不明显(P>0.05),到14月龄时MDA含量升高显著,随着月龄的增加,MDA含量升高越明显(均P<0.05)。腓肠肌中MyoD的表达,与8月龄组比较,12、14月龄组没有明显的统计学差异(P>0.05),16、18、20月龄组MyoD表达明显降低(P<0.05);Myogenin表达随着月龄增加逐渐降低。与8月龄组比较,其余各组Myogenin表达差异有统计学意义(P<0.05)。提示12~14月龄,自然衰老主要影响Myogenin的表达,而对MyoD的表达影响并不明显。结论增龄性大鼠骨骼肌萎缩自然衰老模型较佳的造模时间为12~16月龄,该阶段骨骼肌的萎缩明显,饲养时间适中,既能节省造模时间,节约实验成本,又能保证造模的成功率。
Objective To observe the gastrocnemius wet weight of the body mass ratio,gastrocnemius microstructure morphology,age-related indicators of superoxide dismutase(SOD)activity and malondialdehyde(MDA)content,myogenic regulator〔myogenic biochemical factor(MyoD),muscle satellite cell(Myogenin)〕with the change of different months rats,then evaluate the morphology and related protein expression in rats skeletal muscle of different rats,to provide reference for the study of skeletal muscle model atrophy in SD rats with natural aging.Methods 56 normal male SD rats were randomly divided into 6,8,12,14,16,18 and 20-month-old group.They were fed with natural diet.At the corresponding age of month,two sides of gastrocnemius muscle and blood were taken.After weighing gastrocnemius muscle wet weight,the ratio to the body weight was calculated.After blood centrifugation,the content of SOD and MDA in muscle and serum and the expression of MyoD and Myogenin in muscle were measured.Results After the age of 14 months,the mortality of rats increased gradually with aging.Morphologically,compared with the age of 6 months,the gastrocnemius muscle of the rats at the age of 8 months had not significant atrophy.After the age of 12 months,the gastrocnemius muscle of the rats showed significant atrophy,skeletal muscle cells showed mild degenerative changes.With the increase of age,the gastrocnemius muscle atrophy and muscle fiber senescence necrosis became more obvious.The gastrocnemius muscle of rats showed obvious atrophy and degenerative changes after the age of 12 months,which could meet the requirements of modeling.SOD activity in gastrocnemius muscle and serum of the rats at the age of 12 months was not significantly different from that of the rats at the age of 8 months(P>0.05),it decreased significantly at the age of 14 months,and SOD activity decreased more obvious with the increase of the age(all P<0.05).MDA content in serum and gastrocnemius muscle did not increase significantly at the age of 12 months(P>0.05).At the age of 14 months,MDA content increased significantly,and with the increase of months,MDA content increased more significantly(all P<0.05).Compared with 8-month-old group,there was no significant difference in the expression of MyoD in gastrocnemius muscle between 12-month-old and 14-month-old group(P>0.05),but the expression of MyoD was significantly decreased in 16,18 and 20-month-old groups(P<0.05).The expression of Myogenin decreased with age increasing.Compared with 8-month-old group,the expression of Myogenin in other groups were significantly different(P<0.05).The natural aging could mainly affect the expression of Myogenin,except the expression of MyoD at the age of 12~14 months.Conclusions The better modeling time for the aging model of natural aging rats with skeletal muscle atrophy is the age of 12~16 months,during which skeletal muscle atrophy is obvious and feeding time is moderate,which could not only save modeling time and experimental cost,but also guarantee the success rate of modeling.
作者
张伟波
吴丽洁
高原
温佩彤
寿崟
王晓南
徐平
ZHANG Wei-Bo;WU Li-Jie;GAO Yuan(Zhejiang Province Iongde Hospital,Hangzhou 310013,Zhejiang,China)
出处
《中国老年学杂志》
CAS
北大核心
2022年第22期5570-5574,共5页
Chinese Journal of Gerontology
基金
国家自然科学基金项目(No.81373755)
国家自然科学基金青年科学基金项目(No.81403470)。
