# 纤维化（Fibrosis）

- 器官 / 系统：骨骼肌 / 骨骼肌肉系统（skeletal-muscle / musculoskeletal-system）
- NTP 数据编号：ntp-0592
- 规范 URL：https://www.labsmart.cn/ntp/skeletal-muscle-fibrosis.html
- 中文图谱总页锚点：https://www.labsmart.cn/ntp-atlas.html#skeletal-muscle-fibrosis
- 原始出处：https://ntp.niehs.nih.gov/atlas/nnl/musculoskeletal-system/skeletal-muscle/Fibrosis
- 授权：美国联邦政府作品，公有领域；引用请标注 NTP Nonneoplastic Lesion Atlas
- 适用说明：仅供科研使用，不用于临床诊断

## 一句话结论
在骨骼肌中，纤维化的主要组织学特征是数量增多的丰满的反应性成纤维细胞（伴有明显的泡状核），以及数量增多的淡嗜酸性纤维状物质（胶原沉积），这些物质分隔并环绕相邻的肌纤维（Figure 1、Figure 2、Figure 3、Figure 4）。

## 病变描述（中文）
在骨骼肌中，纤维化的主要组织学特征是数量增多的丰满的反应性成纤维细胞（伴有明显的泡状核），以及数量增多的淡嗜酸性纤维状物质（胶原沉积），这些物质分隔并环绕相邻的肌纤维（Figure 1、Figure 2、Figure 3、Figure 4）。受累的肌纤维可能表现出也可能不表现出萎缩、变性、坏死或再生的组织学特征。纤维化是一系列事件的最终结果，该过程始于组织损伤和炎症，终于永久性瘢痕形成。当组织受损时，浸润的炎症细胞释放促纤维化细胞因子，如转化生长因子β。这些细胞因子发出信号，使成纤维细胞迁移至受累区域，并开始产生和重塑细胞外基质。随后，基质成纤维细胞开始产生细胞因子、生长因子和蛋白酶，进一步触发并维持炎症/促纤维化状态。虽然成纤维细胞对于维持组织稳态和调控正常伤口修复至关重要，但它们也是慢性纤维化疾病形成过程中的关键中间环节。在慢性或广泛性肌肉损伤的情况下，持续性炎症、延长的成纤维细胞活化以及卫星细胞修复能力的减弱最终导致细胞外基质成分的过度积累。这抑制了肌源性修复，并导致肌肉被纤维化/瘢痕组织所取代。虽然营养性、劳力性和中毒性肌病可导致广泛的肌肉损伤区域，但修复往往极为有效，因此纤维化轻微至缺失。相比之下，缺血所致损伤后的修复过程往往无效，可能是由于随后卫星细胞和肌内膜细胞的死亡。因此，广泛的纤维化区域常常是主要特征。

## 诊断与分级建议（NTP 共识，中文）
当纤维化作为原发性改变存在时，应当进行诊断和分级。作为慢性或慢性活动性炎症的次要成分存在的纤维化，仅当其为该病变的显著成分或纤维化程度与炎症程度不相称时（即纤维化比根据炎症严重程度所预期的更为严重），才应当进行诊断。如果未单独诊断纤维化，则应在病理学叙述中对其进行描述。无论何时诊断纤维化，都应根据组织的总体受累程度以及基础架构被遮蔽的程度进行分级。由于纤维化通常是初始炎症过程的最终结果，应在病理学叙述中讨论纤维化的可能原因。其他肌病性改变（例如炎症、坏死、再生）不应单独记录，除非其严重程度足以支持单独记录。

## 英文原文 · Comment
In skeletal muscle, the predominant histologic features of fibrosis are increased numbers of plump reactive fibroblasts with prominent vesiculated nuclei, and increased amounts of pale eosinophilic fibrillar material (collagen deposition) separating and surrounding adjacent myofibers ( Figure 1 , Figure 2 , Figure 3 , and Figure 4 ). Affected myofibers may or may not exhibit histologic features of atrophy, degeneration, necrosis, or regeneration. Fibrosis is the end result of a cascade of events that begins with tissue injury and inflammation and ends in permanent scar formation. When tissue is damaged, profibrotic cytokines, such as transforming growth factor beta, are released by the infiltrating inflammatory cells. These cytokines signal the fibroblasts to migrate into the affected region and to begin producing and remodeling the extracellular matrix. The stromal fibroblasts then begin producing cytokines, growth factors, and proteases that further trigger and uphold the inflammatory/profibrotic conditions. While fibroblasts are fundamental for maintaining tissue homeostasis and regulating normal wound repair, they also serve as a crucial intermediate in the formation of chronic fibrotic diseases. During conditions of chronic or extensive muscle damage, persistent inflammation, prolonged fibroblastic activation, and attenuated reparative capacity of the satellite cells ultimately lead to excessive accumulation of extracellular matrix components. This inhibits myogenic repair and leads to the replacement of muscle with fibrotic/scar tissue. While nutritional, exertional, and toxic myopathies can result in extensive regions of muscle damage, repair is often extremely effective, and thus fibrosis is minimal to absent. In contrast, the reparative process is often ineffective following damage due to ischemia, likely due to the subsequent death of the satellite cells and endomysial cells. For this reason, extensive regions of fibrosis are often a dominant feature.

## 英文原文 · Recommendation
When present as a primary change, fibrosis should be diagnosed and graded. Fibrosis that is present as a minor component of chronic or chronic-active inflammation should be diagnosed only if it is a prominent component of that lesion or if the degree of fibrosis is not commensurate to that of the inflammation (i.e., the fibrosis is more severe than would be expected given the severity of the inflammation). If fibrosis is not diagnosed separately, it should be described in the pathology narrative. Whenever it is diagnosed, fibrosis should be graded based upon the overall involvement of the tissue and the degree to which the underlying architecture is obscured. Since fibrosis is often the end result of an initial inflammatory process, potential causes of the fibrosis should be discussed in the pathology narrative. Additional myopathic changes (e.g., inflammation, necrosis, regeneration) should not be recorded separately unless warranted by severity.

## 配图
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