Department of Rehabilitation Medicine, Shanghai Fourth People's Hospital Affiliated to Tongji University School of Medicine, Shanghai, China.
Department of Rehabilitation Medicine, The General Hospital of Western Theater Command, Chengdu, China.
World Neurosurg. 2022 Jun;162:e475-e483. doi: 10.1016/j.wneu.2022.03.035. Epub 2022 Mar 15.
There is currently no effective treatment for spinal cord injuries (SCIs). Previous studies have shown that every-other-day fasting (EODF), a dietary restriction method, can reduce SCI size and promote motor function recovery, making it a potential novel treatment. However, the mechanism that underlies the positive impact of EODF on SCI remains unclear. Caspase-dependent apoptosis and necroptosis, which involve receptor-interacting protein kinase (RIPK), drive the loss of nerve cells and restrict motor function recovery after SCI. Dietary restriction has a significant inhibitory effect on Caspase and RIPK expression. This study aimed to investigate whether the EODF diet achieves a neuroprotective effect by inhibiting Caspase-dependent apoptosis and RIPK-dependent necroptosis after SCI.
The model rats underwent EODF for 4 weeks before SCI or started EODF diet immediately after SCI. Immunoblotting and immunohistochemical analyses were used to assess the impact of the intervention on protein expression. Apoptosis in the spinal cord was detected by TdT-mediated dUTP nick-end labeling.
Immunoblotting analysis results revealed that the levels of both RIPK1 and RIPK3 proteins in the injury zone were reduced at 6, 12, and 24 hours and at 3 and 7 days after SCI, respectively. Immunohistochemistry results showed that EODF reduced the expression of Caspase-3 and Bax proteins, while prophylactic EODF decreased the rate of apoptosis detected by TdT-mediated dUTP nick-end labeling within 3 days after SCI.
These findings indicate that the mechanism by which EODF exerts neuroprotective effects may be related to the simultaneous inhibition of apoptosis and necroptosis in SCI.
目前，脊髓损伤（SCI）尚无有效的治疗方法。既往研究表明，隔日禁食（EODF）作为一种饮食限制方法，可减小 SCI 损伤体积并促进运动功能恢复，有望成为一种新的治疗方法。然而，EODF 对 SCI 产生积极影响的机制尚不清楚。半胱天冬酶依赖性细胞凋亡和坏死性凋亡（涉及受体相互作用蛋白激酶（RIPK））导致 SCI 后神经细胞丢失并限制运动功能恢复。饮食限制对半胱天冬酶和 RIPK 表达具有显著的抑制作用。本研究旨在探讨 EODF 饮食是否通过抑制 SCI 后半胱天冬酶依赖性细胞凋亡和 RIPK 依赖性坏死性凋亡发挥神经保护作用。
模型大鼠在 SCI 前进行 4 周的 EODF 或 SCI 后立即开始 EODF 饮食。免疫印迹和免疫组织化学分析用于评估干预对蛋白表达的影响。通过 TdT 介导的 dUTP 缺口末端标记法检测脊髓中的细胞凋亡。
免疫印迹分析结果显示，损伤区 RIPK1 和 RIPK3 蛋白水平分别在 SCI 后 6、12 和 24 小时以及 3 和 7 天降低。免疫组织化学结果显示，EODF 降低了 Caspase-3 和 Bax 蛋白的表达，而预防性 EODF 降低了 SCI 后 3 天内 TdT 介导的 dUTP 缺口末端标记法检测到的细胞凋亡率。
这些发现表明，EODF 发挥神经保护作用的机制可能与同时抑制 SCI 中的细胞凋亡和坏死性凋亡有关。
