摘要： 目的 探讨骨骼肌卫星细胞在Duchenne型肌营养不良症中损伤改变以及γ-生育三烯酚（GT3）对DMD基因敲除小鼠卫星细胞保护作用。方法 DMD基因敲除的C57BL/6J小鼠与野生型（WT） C57BL/6J小鼠各18只，随机选取各6只，流式细胞术检测卫星细胞比例、细胞老化率和凋亡率、DNA损伤率；剩余12只DMD基因敲除小鼠和12只野生型小鼠分别予以GT3溶液50 mg/kg或GT3溶剂50 mg/kg皮下注射，流式细胞术检测卫星细胞凋亡率和DNA损伤率，实时荧光定量聚合酶链反应（FQ-PCR）检测凋亡相关基因Bcl-xl、Puma和Bax表达变化。结果 与野生型组相比，DMD基因敲除组小鼠卫星细胞数目减少（t=35.837，P=0.000），细胞老化率（t=12.902，P=0.000）、细胞凋亡率（t=6.864，P=0.000）和DNA损伤率（t=10.585，P=0.000）增加。DMD基因敲除组和野生型组小鼠经GT3溶剂或GT3溶液处理后，卫星细胞凋亡率（F=59.130，P=0.000），凋亡相关基因Bcl-xl （F=54.480，P=0.000）、Puma （F=38.940，P=0.000）和Bax （F=632.300，P=0.000）表达量，DNA损伤率（F=22.990，P=0.000）差异均有统计学意义，其中，与GT3溶剂相比，DMD基因敲除组经GT3溶液处理后细胞凋亡率减少（q=13.820，P=0.000），抗凋亡基因Bcl-xl表达上调（q=12.830，P=0.000），促凋亡基因Puma （q=12.920，P=0.000）和Bax （q=48.050，P=0.000）表达下调，DNA损伤率下降（q=6.950，P=0.000）。结论 DMD基因敲除小鼠卫星细胞数目减少，细胞老化、凋亡和DNA损伤较明显，GT3可部分改善卫星细胞损伤。

关键词: 肌营养不良,杜氏, 卫星细胞,骨骼肌, 生育三烯酚类, 细胞凋亡, DNA损伤, 疾病模型,动物

Abstract: Objective To investigate the damage of skeletal muscle satellite cells in Duchenne muscular dystrophy (DMD) and the protective effect of γ-tocotrienol (GT3) on muscle satellite cells in DMD knockout mice. Methods Total 18 DMD knockout C57BL/6J mice and 18 wild-type (WT) C57BL/6J mice, while 6 DMD knockout mice and 6 WT mice were selected to detect satellites cells proportion, cells aging rate and apoptosis rate, DNA damage rate by flow cytometry. The remaining 12 DMD knockout mice and 12 WT mice were subcutaneously injected with 50 mg/kg GT3 solution or 50 mg/kg GT3 solvent. The apoptosis rate and DNA damage rate of satellite cells were detected by flow cytometry, and the expression changes of apoptosis-related genes Bcl-xl, Puma and Bax were detected by real time fluorescent quantitative polymerase chain reaction (FQ-PCR). Results Compared with WT group, the number of satellite cells in the DMD knockout group was decreased (t=35.837, P=0.000), while the cells aging rate (t=12.902, P=0.000), apoptosis rate (t=6.864, P=0.000) and DNA damage rate (t=10.585, P=0.000) were increased. After the mice in the DMD knockout group and WT group were treated with GT3 solvent and GT3 solution, the cells apoptosis rate (F=59.130, P=0.000), the apoptosis-related gene Bcl-xl (F=54.480, P=0.000), Puma (F=38.940, P=0.000) and Bax (F=632.300, P=0.000) expression levels and DNA damage rate (F=22.990, P=0.000) were significantly different. Compared with GT3 solvent, the apoptosis rate of DMD knockout group was decreased treated with GT3 solution (q=13.820, P=0.000), and the expression of anti-apoptotic gene Bcl-xl was up-regulated (q=12.830, P=0.000), the expression of pro-apoptotic genes Puma (q=12.920, P=0.000) and Bax (q=48.050, P=0.000) were down-regulated, and the DNA damage rate was decreased (q=6.950, P=0.000). Conclusions The proportion of satellite cells in DMD knockout mice was reduced, and the cells aging, apoptosis and DNA damage were more obvious. The GT3 solution could partially improve the satellite cells damage.

Key words: Muscular dystrophy, Duchenne, Satellite cells, skeletal muscle, Tocotrienols, Apoptosis, DNA damage, Disease models, animal