Brain Res. 2010 Jun 18.

Pre-differentiated embryonic stem cells promote functional recovery after spinal-cord compressive injury.

Marques SA, Almeida FM, Fernandes AM, Dos Santos Souza C, Cadilhe DV, Rehen SK, Martinez AM.

Laboratório de Neurodegeneração e Reparo, Laboratório de Regeneração Neural e Função, Instituto de Biologia, Universidade Federal Fluminense, Brazil; Instituro de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Laboratório de Regeneração Neural e Função, Instituto de Biologia, Universidade Federal Fluminense, Brazil.

We tested the effects of mouse embryonic stem cells (mES) grafts in mice spinal-cord injury (SCI). Young adult females C57/Bl6 were subjected to laminectomy at T9 and 1 minute compression of the spinal cord with a vascular clip. Four groups were analyzed: laminectomy (Sham), injured (SCI), vehicle (DMEM) and mES-treated (EST). mES pre-differentiated with retinoic acid were injected (8x10(5) cells/2mul) into the lesion epicenter, 10 minutes after SCI. Basso mouse scale (BMS) and Global mobility test (GMT) were assessed weekly up to 8weeks, when morphological analyses were performed. GMT analysis showed that EST animals moved faster (10.73+/-0.9076,+/-SEM) than SCI (5.581+/-0.2905) and DMEM (5.705+/-0.2848), but slower than Sham animals (15.80+/-0.3887,p<0.001). By BMS, EST animals reached the final phase of locomotor recovery (3.872+/-0.7112,p<0.01) while animals of the SCI and DMEM groups improved to an intermediate phase (2.037+/-0.3994 and 2.111+/-0.3889, respectively). White-matter area and number of myelinated nerve fibers were greater in EST (46.80+/-1.24; 279.4+/-16.33, respectively) than the SCI group (39.97+/-0.925; 81.39+/-8.078,p<0.05 respectively). EST group also presented better G-ratio values when compared with SCI group (p<0.001). Immunohistochemical revealed the differentiation of transplanted cells into astrocytes, oligodendrocytes and Schwann cells, indicating an integration of transplanted cells with host tissue. Ultrastructural analysis showed, in the EST group, better tissue preservation and more remyelination by oligodendrocytes and Schwann cells than the other groups. Our results indicate that acute transplantation of pre-differentiated mES into the injured spinal cord increased the spared white matter and number of nerve fibers, improving locomotor function. Copyright © 2010. Published by Elsevier B.V.