The cellular and molecular mechanisms that presumably underlie the progressive functional decline of the myelomeningocele (MMC) placode are not well understood. We previously identified key players in post-traumatic spinal cord injury cascades in human MMC tissues obtained during postnatal repair. In this study, we conducted experiments to further investigate these mediators in the prenatal time course under standardized conditions in a retinoic acid–induced MMC rat model. A retinoic acid MMC model was established using time-dated Sprague-Dawley rats, which were gavage-fed with all-trans retinoic acid (RA; 60 mg/kg) dissolved in olive oil at E10. Control animals received olive oil only. Fetuses from both groups were obtained at E16, E18, and E22. The spinal cords (SCs) of both groups were formalin-fixed or snap-frozen. Tissues were screened by real-time reverse transcription polymerase chain reaction for the expression of cytokines and chemokines known to play a role in the lesion cascades of the central nervous system after trauma. MMC placodes exhibited inflammatory cells and glial activation in the later gestational stages. At the messenger RNA (mRNA) level, interleukin-1 beta, tumor necrosis factor alpha, and tumor necrosis factor receptor type 1 exhibited significant induction at E22. interleukin-1 beta receptor type 1 mRNA was induced significantly at E16 and E22. Double labeling experiments confirmed the co-staining of these cytokines and their receptors with ionized calcium-binding adapter molecule 1 (i.e., inflammatory cells), vimentin, and nestin in different anatomical SC areas and neuronal nuclear protein in ventral horn neurons. C-X-C motif chemokine 12 mRNA was elevated in control and MMC animals at E16 compared with E18 and E22. C-X3-C motif ligand 1 mRNA was lower in MMC tissues than in control tissues on E16. The presented findings contribute to the concept that pathophysiological mechanisms, such as cytokine induction in the neuroplacode, in addition to the “first hit,” promote secondary spinal cord injury with functional loss in the late fetal time course. Further, these mediators should be taken into consideration in the development of new therapeutic approaches for open spinal dysraphism.

中文翻译：

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脊髓脊膜膨出大鼠神经基板中促炎细胞因子的胎儿和围产期表达谱：对理解开放性脊髓损伤继发性脊髓损伤的贡献

可能导致脊髓脊膜膨出 (MMC) 基板进行性功能衰退的细胞和分子机制尚不清楚。我们之前确定了在产后修复期间获得的人类 MMC 组织中创伤后脊髓损伤级联反应的关键参与者。在这项研究中，我们进行了实验，以在视黄酸诱导的 MMC 大鼠模型中在标准化条件下进一步研究这些介质在产前时间过程中的作用。使用时间确定的 Sprague-Dawley 大鼠建立视黄酸 MMC 模型，在 E10 时用溶于橄榄油的全反式视黄酸 (RA; 60 mg/kg) 灌胃喂养。对照动物仅接受橄榄油。两组胎儿均在 E16、E18 和 E22 获得。两组的脊髓（SCs）均采用福尔马林固定或速冻。组织通过实时逆转录聚合酶链反应筛选已知在创伤后中枢神经系统病变级联反应中起作用的细胞因子和趋化因子的表达。MMC 基板在妊娠后期表现出炎症细胞和神经胶质激活。在信使 RNA (mRNA) 水平，白介素 1 β、肿瘤坏死因子 α 和 1 型肿瘤坏死因子受体在 E22 表现出显着诱导。白细胞介素 1 β 受体 1 型 mRNA 在 E16 和 E22 显着诱导。双标记实验证实了这些细胞因子及其受体与不同解剖学 SC 区域中的离子化钙结合衔接分子 1（即炎症细胞）、波形蛋白和巢蛋白以及腹角神经元中的神经元核蛋白共染色。与 E18 和 E22 相比，在 E16 的对照和 MMC 动物中，CXC 基序趋化因子 12 mRNA 升高。在 E16 上，MMC 组织中的 C-X3-C 基序配体 1 mRNA 低于对照组织。所提出的研究结果有助于提出这样的概念，即除了“第一次打击”外，神经基板中的细胞因子诱导等病理生理机制还会促进继发性脊髓损伤，并在胎儿晚期发生功能丧失。此外，在开发开放性脊柱裂隙症的新治疗方法时，应考虑这些介质。例如神经基板中的细胞因子诱导，除了“第一次打击”外，还会促进继发性脊髓损伤，并在胎儿晚期发生功能丧失。此外，在开发开放性脊柱裂隙症的新治疗方法时，应考虑这些介质。例如神经基板中的细胞因子诱导，除了“第一次打击”外，还会促进继发性脊髓损伤，并在胎儿晚期发生功能丧失。此外，在开发开放性脊柱裂隙症的新治疗方法时，应考虑这些介质。