Neuroprotection.

<p>MSC transplants favor tissue sparing after SCI. Luxol fast blue/hematoxylin staining on cross sections of MSC-grafted (<b>A</b>) and control injured only (<b>B</b>) rats, 21 days after transplantation. The quantification of spared tissue (<b>C</b>), as assessed by the mean ratio of injured area on total area of the sections, reveals a significant decrease of the lesion extension in MSC treated rats compared to control ones. * p<0.05.</p

Blood vessel quantification.

<p>(<b>A</b>–<b>B</b>) RECA-1 immunohistological staining on longitudinal sections of MSC-treated (<b>A</b>) and control vehicle-treated (<b>B</b>) spinal cords. Scale bar: 500 µm. (<b>C</b>) Blood vessel quantification within the lesioned site reveals a significant increase in MSC treated rats compared to control-vehicle treated ones. *p<0.05.</p

Axonal regrowth.

<p>(<b>A</b>–<b>B</b>) GAP43 immunoreactivity on transversal spinal cord sections, 28 days after SCI, in injured + MSC (A) and injured-only (B) groups. Sections were taken at the lesion site. (<b>C</b>) Image analysis doesn't show a significant difference (Student's t-Test, p = 0,23) in the percentage of total lesioned area immunoreactive for GAP43 between treated (2,96 ± 0,35 %) and control (2,25 ± 0,44 %) groups</p

Behavioral analysis.

<p>(<b>A</b>) Locomotor scores as assessed by the BBB rating scale. MSC grafted rats reach significantly higher scores compared to both control groups. Only MSC transplanted rats reach the weight-supporting step level (score of 9). Injured + MSC vs injured only p = 0.0029; injured + MSC vs injured + vehicle p<0.0001. (<b>B</b>) Grid test scores assessing deficits in descending fine motor control. MSC grafted rats reach higher scores, significantly different from control rats. Injured + MSC vs injured only p<0.0001; injured + MSC vs injured + vehicle p<0.0001.</p

Cytokine array and Elisa results.

<p>(<b>A</b>) Cytokine arrays. Spinal cord extracts from injured vehicle-treated (n = 4) and MSC-treated (n = 5) rats. ß-NGF is significantly increased within the lesioned site 3 days after MSC injection compared to controls. * p<0.05 (mean±S.E.). (<b>B</b>) Histogram showing the amounts, in pg/ml, of the neurotrophins NGF and BDNF as quantified by Elisa, within 2 distinct P12 MSC-conditioned media (M1 and M2). (<b>C</b>) NGF and (<b>D</b>) BDNF fluorescent immunocytochemistry on P12 MSCs <i>in vitro</i>. Scale bar : 50 µm.</p

BrdU immunodetection.

<p>(<b>A</b>) BrdU (FITC)-DAPI immunostaining on MSCs cultured with 1.10⁻⁶M BrdU for 72 h, demonstrating that cells were all labeled before being transplanted. (<b>B–C–D</b>) BrdU (Rhodamine) maintenance in MSCs 3 days (<b>B</b>), 7 days <b>(C)</b> and 21 days (<b>D</b>) after the removal of BrdU from the culture medium. (<b>E</b>) BrdU immunodetection (FITC) on a longitudinal spinal cord tissue section from a rat that received 3 ip BrdU injections after spinal cord injury. Scale bar: 50 µm (A), 100 µm (B, C, D) and 200 µm (E).</p

Mesenchymal stem cell characterization.

<p>(<b>A</b>): Phase contrast microphotography of rat MSCs in culture. Cells exhibit typical elongated, fibroblast-like morphology (arrowheads) or large, flattened shape (asterisks). (<b>B</b>) CD90 and (<b>C</b>) CD271 positive immunofluorescent labelings of P4 MSCs in culture, while CD45 <b>(D)</b> and CD11b (<b>E</b>) immunostainings are negative. (<b>F</b>) Adipogenic differentiation of P4-MSCs revealed with Oil Red O. (<b>G</b>) Alizarin Red staining of P4 MSCs induced to osteocytes reveals mineral deposition. (<b>H</b>) Immunofluorescent visualization of nestin induction in P12-MSCs deprived of serum. Nuclei are labeled with the Vectashield-DAPI mounting medium.</p

MSC viability and CD profile.

<p>Nestin (<b>A</b>) and p75NGFr (<b>B</b>) immunofluorescent stainings on MSCs: The last drop of MSC suspension from the injection needle was placed back into culture to check their viability at the time of injection. (<b>C</b>–<b>F</b>): CD profile of P12 MSC grafted cells, showing their immunoreactivity for CD90 (C) and CD271 (D), and the absence of CD45 (E) and CD11b (F) expression. Scale bar: 50 µm (A, B), 100 µm (C–F).</p