Bigbee J W, Yoshino J E, DeVries G H
Department of Anatomy, Medical College of Virginia, Richmond 23298.
J Neurocytol. 1987 Aug;16(4):487-96. doi: 10.1007/BF01668503.
Cultured Schwann cells were found to phagocytose exogenously applied myelin membranes within 1 h. However, the resulting proliferative response required an additional 9 h of incubation. Treatment with ammonium chloride, a lysosomal inhibitor, delayed the appearance of the proliferative response to the myelin membranes by 12 h. Processing of myelin within the Schwann cells was followed by the appearance of immunocytochemically detectable myelin basic protein which was first visible at 4 h. Similar to the proliferative response, the appearance of immunoreactive material was delayed by the addition of ammonium chloride. Schwann cells were observed initially to ingest myelin fragments at their distal-most tips after which time the myelin phagosomes collected in the perinuclear region and fused with lysosomes. Phagocytic Schwann cells had a notable increase in Golgi membranes and microfilaments and contained widely dilated, rough endoplasmic reticulum cisternae. In purified cell cultures, Schwann cells phagocytosed myelin slower than macrophages, but displayed phagocytic abilities much greater than fibroblasts. The ability of cultured Schwann cells to phagocytose myelin rapidly suggests that these cells may aid in the breakdown and removal of myelin during Wallerian degeneration. These data further confirm the mitogenic effect of myelin and its possible role during nerve regeneration.
研究发现，培养的施万细胞在1小时内就能吞噬外源施加的髓鞘膜。然而，由此产生的增殖反应还需要额外9小时的孵育时间。用溶酶体抑制剂氯化铵处理后，对髓鞘膜增殖反应的出现延迟了12小时。施万细胞内髓鞘的处理伴随着免疫细胞化学可检测到的髓鞘碱性蛋白的出现，该蛋白在4小时时首次可见。与增殖反应类似，氯化铵的添加延迟了免疫反应性物质的出现。最初观察到施万细胞在其最远端吞噬髓鞘碎片，之后髓鞘吞噬体聚集在核周区域并与溶酶体融合。吞噬性施万细胞的高尔基体膜和微丝显著增加，并且含有广泛扩张的粗面内质网池。在纯化的细胞培养物中，施万细胞吞噬髓鞘的速度比巨噬细胞慢，但显示出比成纤维细胞大得多的吞噬能力。培养的施万细胞快速吞噬髓鞘的能力表明，这些细胞可能在沃勒变性过程中有助于髓鞘的分解和清除。这些数据进一步证实了髓鞘的促有丝分裂作用及其在神经再生过程中的可能作用。
