Department of Neurosurgery, The Second Hospital of Hebei Medical University, Shijiazhuang, the People's Republic of China.
Neuroreport. 2024 Apr 3;35(6):387-398. doi: 10.1097/WNR.0000000000002020. Epub 2024 Mar 1.
Emerging evidence indicates that dysfunctional autophagic flux significantly contributes to the pathology of experimental traumatic brain injury (TBI). The current study aims to clarify its role post-TBI using brain tissues from TBI patients. Histological examinations, including hematoxylin and eosin, Nissl staining, and brain water content analysis, were employed to monitor brain damage progression. Electron microscopy was used to visualize autophagic vesicles. Western blotting and immunohistochemistry were performed to analyze the levels of important autophagic flux-related proteins such as Beclin1, autophagy-related protein 5, lipidated microtubule-associated protein light-chain 3 (LC3-II), autophagic substrate sequestosome 1 (SQSTM1/p62), and cathepsin D (CTSD), a lysosomal enzyme. Immunofluorescence assays evaluated LC3 colocalization with NeuN, P62, or CTSD, and correlation analysis linked autophagy-related protein levels with brain water content and Nissl bodies. Early-stage TBI results showed increased autophagic vesicles and LC3-positive neurons, suggesting autophagosome accumulation due to enhanced initiation and reduced clearance. As TBI progressed, LC3-II and P62 levels increased, while CTSD levels decreased. This indicates autophagosome overload from impaired degradation rather than increased initiation. The study reveals a potential association between worsening brain damage and impaired autophagic flux post-TBI, positioning improved autophagic flux as a viable therapeutic target for TBI.
新出现的证据表明，功能失调的自噬流对实验性创伤性脑损伤 (TBI) 的病理有重要影响。本研究旨在利用 TBI 患者的脑组织来阐明 TBI 后自噬流的作用。采用苏木精-伊红、尼氏染色和脑水含量分析等组织学检查来监测脑损伤的进展。利用电子显微镜观察自噬小体。通过 Western blot 和免疫组化分析来评估自噬流相关重要蛋白的水平，如 Beclin1、自噬相关蛋白 5、微管相关蛋白轻链 3 （LC3-II）、自噬底物 sequestosome 1（SQSTM1/p62）和溶酶体酶组织蛋白酶 D（CTSD）。免疫荧光分析评估 LC3 与 NeuN、P62 或 CTSD 的共定位，自噬相关蛋白水平与脑水含量和尼氏小体的相关性分析。早期 TBI 结果显示自噬小体和 LC3 阳性神经元增加，提示自噬体的积累是由于增强的起始和减少的清除。随着 TBI 的进展，LC3-II 和 P62 水平增加，而 CTSD 水平下降。这表明自噬体的降解受损导致过载，而不是起始增加。该研究揭示了 TBI 后脑损伤加重与自噬流受损之间的潜在关联，将改善自噬流定位为 TBI 的一个可行的治疗靶点。
