Treatment With Bone Marrow Stromal Cells For Spinal Cord Injury Rats And Their Differentiation To Neural Cells In Vitro

Spinal cord injury (SCI) is a kind of serious disease that can threaten man- kind life and healthy. For the past few years, the patients with SCI to increase gradually by traffic accident, high crash and sports injury. And the incidence is usually high in the youth and the adult. Many of the SCI people result in perma- nent disability, and bring about a huge burden to their family and the society. But nowadays there are no effective and useful methods for SCI in clinical, except for the high-dose intravenous administration of methylprednisolone and surgical in- tervention. Therefore, finding a way to effectively reduce the lesion and even to make the injured axonal regenerate has been being a hot spot in neurobiology re- search all the time. With the development of tissue engineering and the pathology, mechanism cognition of SCI, scientists are raising a new way to cure SCI by tissue engineering. Bone marrow stromal cells (BMSCs) are not haemopoietic stem cells in hematopoietic system. They are one of ideal kind of seed cells of tissue engineering for their easy to obtain, proliferate soon and multi-directional differentiation. In our experiments, we investigated the effect of BMSCs when transplanted into rats after SCI on morphologically for nerve fiber and to explore the differentiation of BMSCs by olfactory ensheathing cells (OECs) conditioned medium.In our first experiment, we used the spinal cord compressive injury model. We transplanted BMSCs into the interspace of the spinal cord lesion site to in- vestigate the promoting effects on axonal regeneration in adult rats. BMSCs can provide eligible microenvironment in the process of haemocytes'formation and differentiation. BMSCs can not only differentiate into bone, cartilage, tendon and ligament under specified inductions, but also can differentiate into neural cells and dendritic cells. During the process of growth and proliferation, BMSCs can secrete some nutrition factors, such as brain-derived neurotrophic factor (BDNF) and vascular endothelial cell growth factor(VEGF). After SCI the spinal cord results in a series of tissue disorganization, apoptosis, necrosis and cavitation formation. We tried to protect nerve fiber by transplanting BMSCs to SCI rats. BMSCs were obtained by adherent culture, and then they were labeled by hoechst and transplanted into interspace of the spinal cord lesion site by microinjector. Four weeks later, we found that BMSCs can survival, migration and differentiate into neural cells. They also can effectively interrupt the formation of cavitation and provide protection for axonal survival and regeneration, but there are no difference (P>0.05) among three groups by BBB scale.In our second experiment, we explored the differentiation of BMSCs by OECs conditioned medium. OECs can secrete some nutrition factors, such as nerve growth factor(NGF), BDNF and glial cell derived neurotrophic factor (GDNF) in their lifetime. Other nutrition factors, such as surface adhesion secreted at the same time. OECs only existed in olfactory nerve system. BMSCs have the ability to multi-directional differentiation. So OECs conditioned medium which contain the nutrition factors maybe have the ability to induce BMSCs differentiate into neural cells. In order to study the different results between the induced and non-induced BMSCs when transplanted into the spinal cord injury rats. We obtained the purified OECs by selective culture medium and cultured in the fibemectin coated plate. After 9~12 days culture, we collected and made OECs conditioned medium, then it being co-cultured with purified BMSCs which are 3th generation. The differentiation of BMSCs were observed under inverted microscope and were identified by immumofluorescence method. After 72h's induction, we found that BMSCs can acquire neuronal morphology and were being immunopositive for neural markers.On the whole, our experiment found that it is useful to transplant BMSCs for axon regeneration and prevent cavity formation after SCI, and also found that neu -ronal differentiation of BMSCs can be obtained by OECs conditioned medium in vitro.