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Abstract：
BACKGROUND: Extracellular matrix (ECM) remodeling in skeletal muscle is a significant factor in the development of sarcopenia. This study aims to evaluate changes in ECM remodeling in the lumbar paravertebral muscles of sarcopenic rats using diffusion-tensor magnetic resonance imaging (DT-MRI) and compare them with histology.
METHODS: Twenty 6-month-old female Sprague Dawley rats were randomly divided into the dexamethasone (DEX) group and the control (CON) group. Both groups underwent 3.0T MRI scanning, including Mensa, T2WI, and DT-MRI sequences. The changes in muscle fibers and extracellular matrix (ECM) of the erector spinal muscle were observed using hematoxylineosin and sirius red staining. The expressions of collagen I, III, and fibronectin in the erector spinae were detected by western blot. Pearson correlation analysis was employed to assess the correlation between MRI quantitative parameters and corresponding histopathology markers.
RESULTS: The cross-sectional area and fractional anisotropy values of the erector spinae in the DEX group rats were significantly lower than those in the CON group (p < 0.05). Hematoxylin eosin staining revealed muscle fiber atrophy and disordered arrangement in the DEX group, while sirius red staining showed a significant increase in collagen volume fraction in the DEX group. The western blot results indicate a significant increase in the expression of collagen I, collagen III, and fibronectin in the DEX group (p < 0.001 for all). Correlation coefficients between fractional anisotropy values and collagen volume fraction, collagen I, collagen III, and fibronectin were - 0.71, -0.94, -0.85, and - 0.88, respectively (p < 0.05 for all).
CONCLUSIONS: The fractional anisotropy value is strongly correlated with the pathological collagen volume fraction, collagen I, collagen III, and fibronectin. This indicates that DT-MRI can non-invasively evaluate the changes in extracellular matrix remodeling in the erector spinal muscle of sarcopenia. It provides a potential imaging biomarker for the diagnosis of sarcopenia.
METHODS: Twenty 6-month-old female Sprague Dawley rats were randomly divided into the dexamethasone (DEX) group and the control (CON) group. Both groups underwent 3.0T MRI scanning, including Mensa, T2WI, and DT-MRI sequences. The changes in muscle fibers and extracellular matrix (ECM) of the erector spinal muscle were observed using hematoxylineosin and sirius red staining. The expressions of collagen I, III, and fibronectin in the erector spinae were detected by western blot. Pearson correlation analysis was employed to assess the correlation between MRI quantitative parameters and corresponding histopathology markers.
RESULTS: The cross-sectional area and fractional anisotropy values of the erector spinae in the DEX group rats were significantly lower than those in the CON group (p < 0.05). Hematoxylin eosin staining revealed muscle fiber atrophy and disordered arrangement in the DEX group, while sirius red staining showed a significant increase in collagen volume fraction in the DEX group. The western blot results indicate a significant increase in the expression of collagen I, collagen III, and fibronectin in the DEX group (p < 0.001 for all). Correlation coefficients between fractional anisotropy values and collagen volume fraction, collagen I, collagen III, and fibronectin were - 0.71, -0.94, -0.85, and - 0.88, respectively (p < 0.05 for all).
CONCLUSIONS: The fractional anisotropy value is strongly correlated with the pathological collagen volume fraction, collagen I, collagen III, and fibronectin. This indicates that DT-MRI can non-invasively evaluate the changes in extracellular matrix remodeling in the erector spinal muscle of sarcopenia. It provides a potential imaging biomarker for the diagnosis of sarcopenia.
摘要：
背景：骨骼肌中的细胞外基质（ECM）重塑是肌肉减少症发展的重要因素。本研究旨在使用扩散张量磁共振成像（DT-MRI）评估少肌症大鼠腰椎旁肌肉ECM重塑的变化，并将其与组织学进行比较。
方法:6月龄雌性SD大鼠20只,随机分为地塞米松(DEX)组和对照组。两组均行3.0TMRI扫描,包括门萨,T2WI,和DT-MRI序列。采用血氧线菌素和天狼星红染色观察勃起脊髓肌纤维和细胞外基质(ECM)的变化。胶原蛋白I的表达，III,用蛋白质印迹法检测竖脊肌中的纤连蛋白。采用Pearson相关分析评估MRI定量参数与相应组织病理学标志物之间的相关性。
结果：DEX组大鼠竖脊肌的横截面积和各向异性分数值明显低于CON组（p<0.05）。苏木精伊红染色显示DEX组肌纤维萎缩和排列紊乱，天狼星红染色显示DEX组胶原体积分数显著增加。蛋白质印迹结果表明I型胶原的表达显著增加,胶原蛋白III，DEX组和纤连蛋白（全部p<0.001）。分数各向异性值与胶原体积分数的相关系数,胶原蛋白I，胶原蛋白III，和纤连蛋白分别为-0.71，-0.94，-0.85和-0.88（全部p<0.05）。
结论：各向异性分数与病理胶原体积分数密切相关，胶原蛋白I，胶原蛋白III，和纤连蛋白.这表明DT-MRI可以无创评估肌肉减少症的勃起脊髓肌细胞外基质重塑的变化。它为诊断肌肉减少症提供了潜在的影像学生物标志物。
方法:6月龄雌性SD大鼠20只,随机分为地塞米松(DEX)组和对照组。两组均行3.0TMRI扫描,包括门萨,T2WI,和DT-MRI序列。采用血氧线菌素和天狼星红染色观察勃起脊髓肌纤维和细胞外基质(ECM)的变化。胶原蛋白I的表达，III,用蛋白质印迹法检测竖脊肌中的纤连蛋白。采用Pearson相关分析评估MRI定量参数与相应组织病理学标志物之间的相关性。
结果：DEX组大鼠竖脊肌的横截面积和各向异性分数值明显低于CON组（p<0.05）。苏木精伊红染色显示DEX组肌纤维萎缩和排列紊乱，天狼星红染色显示DEX组胶原体积分数显著增加。蛋白质印迹结果表明I型胶原的表达显著增加,胶原蛋白III，DEX组和纤连蛋白（全部p<0.001）。分数各向异性值与胶原体积分数的相关系数,胶原蛋白I，胶原蛋白III，和纤连蛋白分别为-0.71，-0.94，-0.85和-0.88（全部p<0.05）。
结论：各向异性分数与病理胶原体积分数密切相关，胶原蛋白I，胶原蛋白III，和纤连蛋白.这表明DT-MRI可以无创评估肌肉减少症的勃起脊髓肌细胞外基质重塑的变化。它为诊断肌肉减少症提供了潜在的影像学生物标志物。
