Morrissey T K, Bunge R P, Kleitman N
Miami Project to Cure Paralysis, University of Miami School of Medicine, Florida 33136, USA.
J Neurobiol. 1995 Oct;28(2):171-89. doi: 10.1002/neu.480280205.
Schwann cells (SCs) play critical roles in regeneration after injury to the peripheral nervous system and can also induce axonal regeneration in the central nervous system. Transplantation of purified SCs into sites of neural injury in rodents has confirmed the remarkable ability of these cells to promote axonal regrowth, suggesting that human application of SC transplantation could be valuable. In this report, we have compared the functional capacities of SCs derived from adult human and rodent nerves by of SCs derived from adult human and rodent nerves by maintaining SCs from these two sources in culture with sensory neurons. We noted that techniques commonly in use for maintaining pure rat SC populations are not sufficient to sustain populations of human SCs free of fibroblasts. In these co-cultures, human SCs express a limited profile of characteristic behaviors and they proliferate more slowly than rat SCs in response to axonal contact. Slow SC proliferation, relative to that of contaminating fibroblasts, leads to a high proportion of fibroblasts in the cultures. After 3 to 4 weeks of co-culture with neurons, human SCs express extracellular matrix molecules, but only partially ensheathe axons, whereas rat SCs differentiate, form basal lamina, and ensheathe or myelinate axons. Co-culture of sensory neurons with human (but not rat) SC preparations (or conditioned medium therefrom) leads to a progressive neuronal atrophy characterized by shrinking neuronal cell bodies and a decrease in the density of the neurite network in the culture dish. As the divergent effects of human and rat SCs on neuronal health were also observed in co-cultures with human sensory neurons, these effects reflect differences between the rat and human-derived SC populations, rather than a species mismatch between SCs and neurons. The marked differences in behavior observed between rat and human SCs derived by the same methods requires further exploration if human-derived SCs are to be considered in the treatment of disease. In a companion article we report experiments that define culture conditions more effective in promoting human SC function in vitro.
施万细胞（SCs）在周围神经系统损伤后的再生中发挥着关键作用，并且还能诱导中枢神经系统中的轴突再生。将纯化的施万细胞移植到啮齿动物的神经损伤部位，已证实这些细胞具有促进轴突再生的显著能力，这表明施万细胞移植在人类应用中可能具有重要价值。在本报告中，我们通过将来自成年人类和啮齿动物神经的施万细胞与感觉神经元一起培养，比较了它们的功能能力。我们注意到，常用于维持纯大鼠施万细胞群体的技术不足以维持无成纤维细胞的人类施万细胞群体。在这些共培养中，人类施万细胞表现出有限的特征性行为，并且它们对轴突接触的反应比大鼠施万细胞增殖更慢。相对于污染的成纤维细胞，施万细胞增殖缓慢导致培养物中存在高比例的成纤维细胞。与神经元共培养3至4周后，人类施万细胞表达细胞外基质分子，但仅部分包裹轴突，而大鼠施万细胞则分化、形成基膜并包裹或髓鞘化轴突。感觉神经元与人类（而非大鼠）施万细胞制剂（或其条件培养基）共培养会导致渐进性神经元萎缩，其特征为神经元细胞体萎缩以及培养皿中神经突网络密度降低。由于在与人类感觉神经元的共培养中也观察到人类和大鼠施万细胞对神经元健康的不同影响，这些影响反映了大鼠和人类来源的施万细胞群体之间的差异，而不是施万细胞与神经元之间的物种不匹配。如果要考虑将人类来源的施万细胞用于疾病治疗，那么通过相同方法获得的大鼠和人类施万细胞之间观察到的行为显著差异需要进一步探索。在一篇配套文章中，我们报告了确定在体外更有效地促进人类施万细胞功能的培养条件的实验。
