Protective role of γ ⁃ tocotrienol on muscle satellite cells of Duchenne muscular dystrophy in mice

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.

doi：10.3969/j.issn.1672⁃6731.2022.09.009