Cyclosporine is one of the foremost immunosuppressive agents for cell, tissue, and organ transplantation. Cyclosporine is, however, associatedwith signicant side e

This study aims to investigate the effect of adenoviral vector-mediated neurotrophine-3 (NT-3) gene transfer and retinoic acid (RA) pretreatmenton inducing neuronal differentiation of bone marrow mesenchymal stem cells (MSCs) in vitro. MSCs could be efficiently transduced by NT-3gene via recombinant adenoviral vectors (Adv). Combination of AdvNT-3 and RA significantly promoted MSCs to differentiate into cell typesassociated with phenotypes of neural lineages, which included neural markers nestin, NF, MAP2 and PSD95 as detected by immunocytochemistry.But the expressions of GFAP in these cells were not obvious. RT-PCR analysis revealed that AdvNT-3 in combination with RA pretreatment couldinitiate the transcription of TrkC mRNA. These results demonstrate that the combination of AdvNT-3 and RA pretreatment may promote neuronaldifferentiation of MSCs, which may serve as ideal seed cells for the repair of spinal cord injury.

The present study investigates whether Schwann cells(SCs) could promote the survival and differentiation ofneural stem cells in the injured spinal cord. Neural stemcells were dissociated and cloned from the hippocampaltissue of newborn rats. SCs were also dissociated andpurified simultaneously from the sciatic nerves of 4-dayoldrats. The results showed that the number of survivingneural stem cells and differentiated neuron-like cells wassignificantly increased in the co-grafted (SCs and neuralstem cells) group compared with the control group (neuralstem cells only). Neuron-like cells that developedaxon-like processes were observed more commonly inthe cograftedgroup. These results demonstrate thatSCs can promote the survival and differentiation oftransplanted neural stem cells in the injured spinal cord.

Spinal cord transection results in severe neurological sequelae, and to date, there is no effective treatment. Because of the limited capacity for axonal regeneration in the spinal cord, recovery is minimal. Recently, efforts have been made to establish, by grafting neural tissue, a functional relay-station between the severed stumps of the injured cord. Previously, we used co-transplantation of neural stem cells (NSCs) and Schwann cells (SCs) to improve functional recovery of transected spinal cord. However, this effort has been partially impeded by limited neuronal differentiation of transplanted NSCs. To circumvent this problem, we have pre-differentiated NSCs toward neurons in vitro with the application of retinoic acid (RA) prior to cell grafting. Further, we genetically modifiedSCs to overexpress human neurotrophin-3 (hNT-3). When these cells were co-transplanted into the transected spinal cord of rats, injured animals had partial improvement (both functionally and structurally), including improved Basso, Beattie, and Bresnahan (BBB) scores, increased axonal regeneration/remyelination, and reduced neuronal loss. However, this pre-differentiation of NSCs in vitro only mildly improved neuronal differentiation of NSCs in vivo.

Morphological changes of CA1 and CA3 pyramidal neurons in rat hippocampus at different intervals following transientforebrain ischemia were examined to determine the nature of post-ischemic cell death in these regions. In the CA1 region, swellingof small dendrites occurred at 24h reperfusion. At 48 h reperfusion, swelling was found in large dendrites of many CA1neurons and the mitochondria and endoplasmic reticulum (ER) were dilated. A small portion of neurons showed chromatinaggregation and nuclear indentation without swelling signs. At 60h reperfusion, swelling of somata was evident in manyneurons. Large dense chromatin clumps with round or ovoid contour were found in other neurons. At 72 and 96 h after ischemia,many large vacuoles and glias with active phagocytosis were observed. At 7 days after ischemia, the tissue was compact and manyglias were found in the region. Most of theCA3 neurons had normal appearance after ischemia. A total of 5-10% CA3 neuronsexhibited shrinking nuclei and chromatin aggregation at 24h reperfusion. The number of these neurons decreased overtime anddisappeared at 72h after ischemia. These results demonstrate the co-existence of necrosis andapoptosis in the CA1 region aftertransient forebrain ischemia. Most CA3 neurons remained intact after ischemia while a small portion of them showed apoptoticcell death.