Duchenne muscular dystrophy (DMD) is a debilitating disorder related to dystrophin encoding gene mutations, often associated with dilated cardiomyopathy. However, it is still unclear how dystrophin deficiency affects cardiac sarcomere remodeling and contractile dysfunction. We employed second harmonic generation (SHG) microscopy, a nonlinear optical imaging technique that allows studying contractile apparatus organization without histologic fixation and immunostaining. Images were acquired on alive DMD (mdx) and wild type cardiomyocytes at different ages and at various external calcium concentrations. An automated image processing was developed to identify individual myofibrils and extract data about their organization. We observed a structural aging-dependent remodeling in mdx cardiomyocytes affecting sarcomere sinuosity, orientation and length that could not be anticipated from standard optical imaging. These results revealed for the first time the interest of SHG to evaluate the intracellular and sarcomeric remodeling of DMD cardiac tissue in an age-dependent manner that could participate in progressive contractile dysfunction.

Duchenne 肌营养不良症 (DMD) 是一种与肌营养不良蛋白编码基因突变相关的使人衰弱的疾病，通常与扩张型心肌病有关。然而，目前尚不清楚肌营养不良蛋白缺乏如何影响心脏肌节重塑和收缩功能障碍。我们采用了二次谐波产生 (SHG) 显微镜，这是一种非线性光学成像技术，可以在没有组织学固定和免疫染色的情况下研究收缩装置的组织。在不同年龄和不同外部钙浓度下，在活的 DMD ( mdx)和野生型心肌细胞上获取图像。开发了一种自动图像处理来识别单个肌原纤维并提取有关其组织的数据。我们在mdx 中观察到结构老化依赖性重塑影响肌节弯曲度、方向和长度的心肌细胞，这是标准光学成像无法预测的。这些结果首次揭示了 SHG 有兴趣以年龄依赖性方式评估 DMD 心脏组织的细胞内和肌节重塑，这可能参与进行性收缩功能障碍。