ABSTRACT
Recovery in central nervous system [CNS] disorders is hindered by the limited ability of the vertebrate CNS to regenerate and replace damaged myelin, and re-establish functional neural connections. In spinal cord injury and other traumas, demyelination of intact axons is an important factor contributing to loss of function. Previous studies suggest that substantial recovery of function might be achieved through remyelination of damaged axons. This study examined the effects of Triiodothyronine [T3] on in vitro trans-differentiation of adult rat bone marrow stromal stem cells [BMSCs] into oligodendrocyte - like cells [OLCs]. This research was performd experimentally. Under strile conditions, BMSCs were isolated from female sprague-dawley rats. BMSCs were evaluated for different markers such as fibronectin, CD44, CD90, oct4 and CD45. OLCs transdifferentiated from BMSCs by sequential exposure of BMSCs to DMSO and RA in preinduction stage and then induced by heregulin, PDGF-AA, bFGF, and T3 at the induction stage. In both stages of preinduction and induction, the experssion of CD45, CD90, CD44, fibronectin, nestin, Oligo2, O4, NF68, NF160, GFAP, and O1 were assassed by RT-PCR and immunocytochemistry. Our results from immunocytochemistry showed that the fibronectin, CD44, CD90, and CD45 were expressed 94.32 +/- 0.45%, 95.48 +/- 0.24% and 97.16 +/- 0.82% [p< 0.05]. Assessment of of O1, O4 and oligo2 experssion showed that in the induction stage, combination of HRG, PDGF, bFGF and T3 [25ng/ml] have an effective role in transdifferentiation of BMSCs into OLCs. DMSO and RA can transdifferente BMSCs into NeuroProgenitor Cells [NPC] and these cells can be differentiated into OLCs by combination of HRG, PDGF, bFGF and T3 [25ng/m]l.
ABSTRACT
Demyelination of CNS axons occurs under pathological conditions such as multiple sclerosis and spinal cord injuries, but can be repaired by cell therapy. Within the CNS remyelination can be achieved by transplantation of neural stem cells [NSCs]. NSCs are self-renewing cells that maintain the capacity to differentiate into CNS-specific cell types and can differentiate into the three main neural phenotypes: astroglia, oligodendroglia and neurons. They may also replace or repair diseased CNS tissue. Bone marrow stromal cells [BMSCs] were aseptically isolated from the tibia and femurs of young adult Sprague Dawley rats. BMSCs were evaluated by fibronectin and CD31 markers. BMSC-derived NSCs were evaluated by nestin and NF-68. An ethidium bromide-induced demyelinated dorsal column lesion was produced in young adult rats. Transplanting NSCs derived-BMSCs into demyelinated lesions after 3 days in adult rat spinal cords was done. Three weeks after transplantation of NSCs, the spinal cords were processed to evaluate remyelination by Luxol fast blue staining. After passage 3, BMSCs were evaluated and the result, showed the percentage of immunoreactive cells to fibronectin [94.7 +/- 2.65], however BMSC-derived NSCs expressed nestin [86.15 +/- 0.64] and NF-68 [84.55 +/- 0.94] which correlated with fibronectin down regulation. Histologically, the lesions showed slightly irregular elongated areas and had an average length of 1336.36 +/- 39.43 microm. Transplanted NSCs were capable of eliciting remyelination. These data support the conclusion that transplantation of NSCs results in functional remyelination of a dorsal column lesion and have valuable applications in the treatment of neurodegenerative diseases such as spinal cord injuries