Objective: To characterize the paraspinal muscles of adolescent idiopathic scoliosis (AIS) patients, and to further explore its etiology.
Methods: Clinical records and paraspinal muscle biopsies at the apex vertebra region during posterior scoliosis correction surgery of 18 AIS were collected from November 2018 to August 2019. Following standardized processing of fresh muscle tissue biopsy, serial sections with conventional hematoxylin-eosin (HE) and histochemical and immunohistochemical (IHC) with antibody Dystrophin-1 (R-domain), Dystrophin-2 (C-terminal), Dystrophin-3 (N-terminal), Dystrophin-total, Myosin (fast), major histocompatibility complex 1 (MHC-1), CD4, CD8, CD20, and CD68 staining were obtained. Biopsy samples were grouped according to the subjects' median Cobb angle (Cobb angle ≥ 55° as severe AIS group and Cobb angle < 55° as mild AIS group) and Nash-Moe's classification respectively, and the corresponding pathological changes were compared between the groups statistically.
Results: Among the 18 AIS patients, 8 were in the severe AIS group (Cobb angle ≥55°) and 10 in the mild AIS group (Cobb angle < 55°). Both severe and mild AIS groups presented various of atrophy and degeneration of paraspinal muscles, varying degrees and staining patterns of immune-expression of Dystrophin-3 loss, especially Dystrophin-2 loss in severe AIS group with significant differences, as well as among the Nash-Moe classification subgroups. Besides, infiltration of CD4+ and CD8+ cells in the paraspinal muscles and tendons was observed in all the patients while CD20+ cells were null. The expression of MHC-1 on myolemma was present in some muscle fibers.
Conclusion: The histologic of paraspinal muscle biopsy in AIS had similar characteristic changes, the expression of Dystrophin protein was significantly reduced and correlated with the severity of scoliosis, suggesting that Dystrophin protein dysfunctions might contribute to the development of scoliosis. Meanwhile, the inflammatory changes of AIS were mainly manifested by T cell infiltration, and there seemed to be a certain correlation between inflammatory cell infiltration, MHC-1 expression and abnormal expression of Dystrophin. Further research along the lines of this result may open up new ideas for the diagnosis of scoliosis and the treatment of paraspinal myopathy.
目的: 研究青少年特发性脊柱侧凸(adolescent idiopathic scoliosis, AIS)患者椎旁肌病理改变, 并进一步探讨抗肌萎缩蛋白(Dystrophin)在该病中的表达情况及其与病因的关系。
方法: 收集2018年11月至2019年8月于北京大学第三医院诊断为AIS并接受后路侧弯矫形手术, 术中行凹侧顶椎椎旁肌活检患者18例。对肌肉活检组织进行规范化处理并切片进行常规苏木精-伊红(hematoxylin-eosin, HE)染色、多种组织化学染色以及抗肌萎缩蛋白各亚型、肌球蛋白、主要组织相容性复合体1(major histocompatibility complex 1, MHC-1)、CD4、CD8、CD20、CD68抗体的免疫组织化学染色及结果判读分析。此外, 根据Cobb角大小(≥55°或＜55°)和Nash-Moe分类将活检标本分为不同组别, 进行相应病理改变的组间差异统计学比较。
结果: 18例患者中, 重度AIS组(Cobb角≥55°)8例, 轻度AIS组(Cobb角 < 55°)10例, 两组患者椎旁肌均出现不同程度萎缩、变性, Dystrophin-3的免疫组织化学染色均不同程度缺失且表达模式异常。两组活检肌纤维的Dystrophin-2的免疫组织化学染色切片中的表达模式存在显著差异, 重度AIS组的Dystrophin-2表达异常或缺失更显著。根据Nash-Moe分型分组, 患者椎旁肌的Dystrophin-2表达模式也有显著差异, 表现为侧凸程度越重, Dystrophin-2表达异常越显著。此外, 椎旁肌肉组织的肌肉和肌腱中存在CD4+细胞和CD8+细胞的浸润, 而CD20+细胞为阴性。全部患者椎旁肌均有部分肌纤维呈MHC-1肌膜阳性表达。
结论: AIS患者椎旁肌活检的组织学具有相似的特征性改变, 抗肌萎缩蛋白的表达不同程度降低或缺失, 并且与脊柱侧凸程度有一定相关性, 提示抗肌萎缩蛋白功能障碍在脊柱侧凸的发生和发展中具有一定的意义。同时, AIS的炎症改变以T细胞浸润为主要表现, 炎症细胞浸润、MHC-1表达与抗肌萎缩蛋白异常表达之间似有一定的相关性。沿此结果进一步的研究可能为AIS的诊断和针对椎旁肌病变的治疗开辟新的思路。
Keywords: Adolescent; Biopsy; Dystrophin protein; Paraspinal muscles; Scoliosis.