骨骼肌挫伤修复过程中巨噬细胞的趋化机制

The Mechanism of Macrophage Chemotaxis during the Repair Process Following Contusion of Skeletal Muscle

目的:探究巨噬细胞在挫伤骨骼肌修复过程中的趋化机制。方法:将66只ICR雄性小鼠随机分为对照组(C组,n=11)和骨骼肌挫伤组(S组,n=55)。骨骼肌挫伤后12h、1d、5d、10d和15d分别取双侧腓肠肌。HE染色观察骨骼肌挫伤后修复过程中的形态学变化,荧光定量PCR检测骨骼肌挫伤后巨噬细胞和趋化因子的时空表达规律。结果:①骨骼肌挫伤后12h,可见肌纤维坏死、肿胀和大量炎性细胞浸润。伤后第5天,可见少量再生肌纤维,伤后第10天再生肌纤维数量大大增加,伤后第15天虽有少量再生肌纤维,但肌纤维结构完整性较好,骨骼肌损伤修复基本完成。②与对照组相比,M1巨噬细胞标志物(CD68)在骨骼肌挫伤后显著增加,随后M2巨噬细胞标志物(CD206和CD163)显著增加。③骨骼肌挫伤后MCP-1及其受体CCR2mRNA表达均显著增加(P<0.01)。SDF-1mRNA在挫伤后12h、10d和15d表达均显著增加(P<0.01),其受体CXCR4表达无显著变化。④骨骼肌挫伤后,MCP-1与CD68存在强相关,亦与其受体CCR2呈强相关,而SDF-1只与其受体CXCR4相关。结论:MCP-1/CCR2轴可能参与了挫伤骨骼肌修复过程中M1巨噬细胞的趋化。

Objective: The objective of this study is to explore the mechanism of macrophage chemotaxis during the repair process following contusion of skeletal muscle. Methods: 66 ICR male mice were randomly divided into control group(C group, n =11) and muscle contusion group(S group, n =55).Their gastrocnemius muscles were harvested at the time points of 12 h,1 d,5 d,10 d and 15 d post-injury. The changes in skeletal muscle morphology were assessed by HE staining. The gene expression of macrophage and chemokines was analyzed by real-time PCR. Results:① On 12 h post-injury, cross sections of gastrocnemius muscles showed substantial fiber damage and inflammatory infiltrate.On day 5 post-injury,a small quantity of centronucleated myofibers were observed.On day 10 post-injury,central nucleation phenomenon became more pronounced.On day 15 post-injury,central nucleation almost disappeared.② The molecule marker of M1 macrophages(CD68) increased significantly post-injury,and the molecule marker of M2 macrophages(CD206 and CD163) increased significantly later.③ MCP-1 and CCR2 mRNA increased significantly post-injury( P <0.01).SDF-1 mRNA increased significantly at 12 h,10 d and 15 d ( P <0.01).However,CXCR4 mRNA did not change significantly post injury.④ The results showed that there was significant correlation between MCP-1 and CD68,and CCR2.In addition,there was significant correlation between SDF-1 and CXCR4. Conclusion: MCP-1/CCR2 may be involved in the chemotaxis of M1 macrophages during skeletal muscle regeneration post-injury.