Abstract

Purpose of study: To study the role of the immune response in spinal cord injury, we previously investigated the effects of genetic deletion of functional T- and B-lymphocytes in recombination activating gene 2 (Rag2)-deficient mice. To dissect out another defined and more restricted component of the immune system, we now analyzed mice deficient in perforin, an enzyme with proteolytic activity expressed mainly by natural killer and cytotoxic lymphocytes.

Materials and methods

Locomotor outcomes in perforin-deficient (Pfp-/-) mice and wild-type littermate controls were measured after severe compression injury of the lower thoracic spinal cord up to six weeks after injury.

Results

According to both the Basso mouse scale score and single frame motion analysis, motor recovery of Pfp-/- mice was similar to wild-type controls. Interestingly, immunohistochemical analysis of cell types at six weeks after injury showed enhanced cholinergic reinnervation of spinal motor neurons caudal to the lesion site and neurofilament-positive structures at the injury site in Pfp-/- mice, whereas numbers of microglia/macrophages and astrocytes were decreased compared with controls.

Conclusions

We conclude that, although, loss of perforin does not change the locomotor outcome after injury, it beneficially affects diverse cellular features, such as number of axons, cholinergic synapses, astrocytes and microglia/macrophages at or caudal to the lesion site. Perforin’s ability to contribute to Rag2’s influence on locomotion was observed in mice doubly deficient in perforin and Rag2 which recovered better than Rag2-/- or Pfp-/- mice, suggesting that natural killer cells can cooperate with T- and B-cells in spinal cord injury.

中文翻译：

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穿孔素影响小鼠脊髓损伤模型的再生

摘要

研究目的：为了研究免疫反应在脊髓损伤中的作用，我们之前研究了功能性 T 和 B 淋巴细胞的基因缺失对重组激活基因 2 (Rag2) 缺陷小鼠的影响。为了剖析免疫系统中另一个明确且更受限制的成分，我们现在分析了缺乏穿孔素的小鼠，穿孔素是一种主要由自然杀伤细胞和细胞毒性淋巴细胞表达的具有蛋白水解活性的酶。

材料和方法

在下胸脊髓严重压缩损伤后长达六周，测量穿孔素缺陷 (Pfp-/-) 小鼠和野生型同窝对照小鼠的运动结果。

结果

根据 Basso 小鼠量表评分和单帧运动分析，Pfp-/- 小鼠的运动恢复与野生型对照相似。有趣的是，在损伤后六周对细胞类型的免疫组织化学分析显示，在 Pfp-/- 小鼠中，损伤部位尾部的脊髓运动神经元和损伤部位的神经丝阳性结构的胆碱能再神经支配增强，而小胶质细胞/巨噬细胞和星形胶质细胞的数量则减少了。与对照组相比有所下降。

结论

我们得出结论，尽管穿孔素的损失不会改变损伤后的运动结果，但它有益地影响多种细胞特征，例如损伤部位或尾部的轴突、胆碱能突触、星形胶质细胞和小胶质细胞/巨噬细胞的数量。在穿孔素和 Rag2 双重缺乏的小鼠中观察到穿孔素对 Rag2 对运动的影响的能力，其恢复比 Rag2-/- 或 Pfp-/- 小鼠更好，这表明自然杀伤细胞可以与脊髓中的 T 细胞和 B 细胞合作脊髓损伤。