It has been reported that children may respond better than adults to a spinal cord injury (SCI) of similar severity. There are known biomechanical differences in the developing spinal cord that may contribute to this “infant lesion effect,” but the underlying mechanisms are unknown. Using immunohistochemistry, we have previously demonstrated a different injury progression and immune cell response after a mild thoracic contusion SCI in infant rats, as compared to adult rats. Here, we investigated the acute inflammatory responses using flow cytometry and ELISA at 1 h, 24 h, and 1 week after SCI in neonatal (P7) and adult (9 weeks) rats, and locomotor recovery was examined for 6 weeks after injury. Adult rats exhibited a pronounced pro-inflammatory response characterized by neutrophils and M1-like macrophage infiltration and Th1 cytokine secretion. Neonatal rats exhibited a decreased pro-inflammatory response characterized by a higher proportion of M2-like macrophages and reduced Th1 cytokine responses, as compared to adults. These results suggest that the initial inflammatory response to SCI is predominantly anti-inflammatory in very young animals.
Dev Neurosci

中文翻译：

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新生大鼠在脊髓损伤后表现出主要的抗炎反应

据报道，儿童对类似严重程度的脊髓损伤 (SCI) 的反应可能比成人更好。发育中的脊髓存在已知的生物力学差异，这可能导致这种“婴儿病变效应”，但潜在的机制尚不清楚。使用免疫组织化学，我们之前已经证明，与成年大鼠相比，婴儿大鼠轻度胸挫伤 SCI 后的损伤进展和免疫细胞反应不同。在这里，我们使用流式细胞术和 ELISA 在新生儿 (P7) 和成年 (9 周) 大鼠 SCI 后 1 小时、24 小时和 1 周研究急性炎症反应，并在损伤后检查运动恢复 6 周。成年大鼠表现出明显的促炎反应，其特征是中性粒细胞和 M1 样巨噬细胞浸润和 Th1 细胞因子分泌。与成人相比，新生大鼠的促炎反应减少，其特征是 M2 样巨噬细胞比例更高，Th1 细胞因子反应减少。这些结果表明，对 SCI 的初始炎症反应在非常年幼的动物中主要是抗炎的。
开发神经科学