Protective effects of MSC-co-culture and of MSC conditioned medium (MSC CM) against STS toxicity in motor neurons.

<p>A: The co-cultivation of motor neurons on MSC showed a slight but not significant protective effect against STS toxicity, with greater STS-sensitivity of SOD1G93A motor neurons. Values represent means ± SEM, ***<i>p</i><0.001, *<i>p</i><0.05, two-way ANOVA with Bonferroni post-test. B: Photographs show representative motor neuron cultures at DIV 7 (B). a: SOD1G93A transgenic motor neuron monoculture without any treatment. b: Reduction of SMI 32 positive motor neurons following exposure to 0.1 µM STS. c: Increase in motor neuron survival due to co-cultivation on MSC. Motor neurons were stained by an antibody against SMI 32 (red). MSC were immunopositive for CD44 (green). Stained nuclei of cultured cells appear in blue (DAPI). Scale bar 100 µm. C: STS-induced apoptosis was attenuated best by 40% dilution of MSC CM, whereas at concentrations higher than 50% CM did not mediate neuroprotection. SOD1G93A motor neurons were significantly more sensitive to STS than non-transgenic motor neurons. Values represent means ± SEM, ***<i>p</i><0.001, **/^##<i>p</i><0.01, *<i>p</i><0.05, two-way ANOVA with Bonferroni post-test. D: Immunostainings revealed the apoptotic morphology of motor neurons after STS treatment (b) and the protective effect of MSC CM (c).