Objective To observe the expressions of CXC chemokine receptor 4 (CXCR4) in muscle satell ite cells in situ of normal and cardiotoxin-intoxicated muscle tissues so as to further investigate the molecular mechanism involving inmuscle regeneration such as progressing muscular dystrophy (PMD) for seeking the way to cure muscle retrogression. Methods The muscle injured model of 12 C57 male mice was made by injecting cardiotoxin (5 μg per mouse) in left quadriceps femoris, their right quadriceps femoris was used as control without any injection. The histological, immunohistochemical analysis and RT-PCR were done to investigate the expression of CXCR4 in the quadriceps femoris in situ after 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks. Results HE staining results demonstrated that the muscle tissues experienced the process from muscle injury, repair to regeneration. The result of immunohistochemistry showed that the expressions of CXCR4 in injured muscle tissue were 1 955.6 ± 150.3, 2 223.2 ± 264.3, 2 317.6 ± 178.7, 3 066.5 ± 269.6, 1 770.9 ± 98.7 and 1 505.7 ± 107.1 at 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks after injection of cardiotoxin, there was significant difference when compared with normal muscle (640.3 ± 124.0, P lt; 0.001). The RT-PCR showed that the expressions of CXCR4 mRNA in injured muscle tissue were0.822 ± 0.013, 0.882 ± 0.025, 1.025 ± 0.028, 1.065 ± 0.041, 0.837 ± 0.011 and 0.777 ± 0.015 at 1 day, 4 days, 1 week, 2 weeks, 4 weeks and 6 weeks after injection of cardiotoxin, there was significant difference when compared with normal muscle (0.349 ± 0.006, P lt; 0.001). Conclusion CXCR4 may be the critical protein in the process of muscle impairment and reparation.
