miRNA-206及miRNA-26a在周围神经卡压后骨骼肌纤维化过程中的表达

Expression and role of miRNA-206 and miRNA-26a on skeletal muscle fibrosis after the peripheral nerve chronic compression injury

目的探讨大鼠坐骨神经慢性卡压损伤后其支配的腓肠肌组织内miRNA-206、miRNA-26a的表达变化及其意义。方法2020年5月至2020年7月,选取50只成年雄性SD大鼠;大鼠右侧后腿采用Mackinnon建立的坐骨神经卡压模型方法对坐骨神经行硅胶管卡压术,作为手术组(实验组);对大鼠左侧后腿仅分离暴露坐骨神经,作为假手术组(对照组)。于卡压术后2、4、6、8、10周时间点随机取大鼠10只,取其双后腿腓肠肌,观察腓肠肌组织萎缩及纤维化程度,并行组织形态学观察,RT-PCR定量测定miRNA-206、miRNA-26a、转化生长因子-β(TGF-β)、Ⅰ型胶原蛋白(COL-Ⅰ)的表达。结果坐骨神经慢性卡压损伤后,手术组与假手术组相比,腓肠肌组织湿重明显减轻,肌肉横截面积变小,肌肉组织胶原纤维增生,miRNA-206及miRNA-26a的表达先降低后升高,4周时表达最低,后表达逐渐升高;TGF-β及COL-Ⅰ含量升高,两组比较差异统计学意义(P<0.05)。结论周围神经慢性卡压损伤可致支配骨骼肌发生纤维化病变,TGF-β及COL-Ⅰ表达升高,miRNA-206及miRNA-26a在此过程中表达先降低后升高,提示miRNA-206及miRNA-26a在周围神经卡压致骨骼肌萎缩及纤维化过程中起到重要作用。

Objective To investigate the effects of mi RNA-206 and mi RNA-26a on skeletal muscle fibrosis after the peripheral nerve chronic compression injury.Methods From May 2020 to July 2020,50 adult male SD rats were selected.The right hind legs of rats were undergone sciatic nerve entrapment operation according to the method which Mackinnon adopted when he established the model of chronic sciatic nerve compression(experimental group).The left hind legs of rats were undergone the sham operation of exposing the sciatic nerve only(control group).Ten rats were randomly selected at2,4,6,8 and 10 weeks after operation,and the gastrocnemius muscle of both hind legs was taken to observe the degree of tissue atrophy and fibrosis of the muscle.Histological observation was conducted,and RT-PCR was performed to determine the expressions of mi RNA-206,mi RNA-26a,transforming growth factor-β(TGF-β),and collagen-Ⅰ(COL-Ⅰ).Results After chronic sciatic nerve compression injury,the wet weight of gastrocnemus muscle tissue was significantly reduced in the operation group compared with the sham operation group,while the cross-sectional area of muscle was smaller.The expression of mi RNA-206 and mi RNA-26a in muscle tissue was firstly decreased and then increased,and the expression of mi RNA-206 and mi RNA-26a were the lowest at 4 weeks,then gradually increased.TGF-βand COL-Ⅰcontents were increased,and there were significant statistical differences between the two groups(P<0.05).Conclusion Chronic entrapment injury of peripheral nerve can lead to fibrosis of dominant skeletal muscle,and increase the expressions of TGF-βand COL-Ⅰ,while the expressions of mi RNA-206 and mi RNA-26a are firstly decreased and then increased in this process.It is suggested that mi RNA-206 and mi RNA-26a play an important role in the process of skeletal muscle atrophy and fibrosis induced by peripheral nerve entrapment.