CONDITIONING OF STEM CELLS WITH BRAIN EXTRACT DERIVED FROM TRAUMATIZED ANIMALS INDUCES RAPID NEURONAL DIFFERENTIATION

Abstract

It was our aim to analyze the effect of cerebral tissue extract derived from traumatized and healthy rats on the release of neurotrophic factors by embryonic stem (ES) cells and on ES cell differentiation in vitro. Methods: Brain injury in male Sprague Dawley rats was induced by Fluid Percussion (2.4 atm). Brain extracts were derived by pooling cerebral hemispheres of traumatized (TE) or healthy (HE) rats. Secretion of neurotrophic factors BDNF, NGF and NT-3 was examined in supernatant of murine ES cells at day 3, 5, 7 and 10. In vitro differentiation of ES cells was examined by expression analysis of oct-4, nestin, fgf, brachyury, gata6 and map2 as well as immuno-histochemical using NeuN Abs. Results: Es cells exhibited an intrinsic ability to produce neurotrophins. BDNF release was significantly increased within 3 days following treatment with cerebral extract (TE, day3: 152% ± 5.3%, P < 0,001). NGF and NT-3 release was significantly decreased following conditioning with brain extract. Differences observed in neurotrophin release due to extract origin (healthy or injured animals) were at no time point statistically relevant. In parallel brain extract induced lineage specific differentiation of ES cells. oct-4 expression was significantly decreased. fgf and nestin expression was increased in all groups, indicating the onset of neural development. Furthermore, ES cells treated with trauma extract developed axonal outgrowth and were stained positive for NeuN within 3 days following conditioning. Conclusion: Conditioning of ES cells with brain extract (TE or HE) seems to trigger a neuronal response. The marked increase of BDNF release might contribute to the protective effects observed following ES cell transplantation. Furthermore, our results indicate that the post traumatic inflammatory microenvironment might support neuronal differentiation.Figure