Study Of NGF-mRNA,NGF And P75 Expression By Sensory And Motor Schwann Cells During Nerve Specific Regeneration

After nerve injury, the regenerating axons can specifically re-grow into distal target organs. Now it is accepted that Schwann cells play a central role in this process for its ability of secreting neurotrophic factors and extracellular matrix that will promote and guide axons regeneration. The purpose of this study is to test if there is biological difference between sensory Schwann cells and motor Schwann cells by measuring the expression of NGF-mRNA, NGF and p75 receptor of the cultured Schwann cells in vitro. Some results are below: 1. Using tissue-digestion and drug-inhibition, Schwann cells of high purity was prepared and identified by in-ununo-fluorescent staining. 2. The patterns of p75 expression between SSc and MSc were different. In common culture media, S Sc's p75 expression reached the peak at the fifth day, and that of MSc's was relatively lower and plainer. After adding IL-i, two kinds of Sc showed similar expressing pattern, they all had a peak expression at 5th day and went down with time passed by. 3. As a whole, the NGF expression of SSc was higher than that of MSc. SSc's expression curve had two peaks and MSc's only one. Adding IL-i seemly did not affect the NGF expression very much to both kinds of Schwann cells. But multiple factors analysis showed that there was probably difference after IL-i treatment according to the Time factor. 4. The expression of NGF-mRNA was different between SSc and MSc. The former was higher by co-culturing with sensory neuron, the latter showed no much difference compared with the blank control. Conclusions: 1. There is no remarkable difference between SSc and MSc under the microscope observation. 2. Acc rding to textbook and papers, there is no significant difference between SSc and MSc about the cell structure and enzyme system. Maybe the difference lies in the living state. 3. The expression of p75 and NGF reflects the functional states of Schwann cells, which may explain why and how the axons specifically regenerate after nerve injuries. 4. From the results, we could see that SSc and MSc are different in some aspects. SSc expresses NGF more and earlier, which may act on sensory nerve fibers to regenerate. Conversely, MSc is less active to IL-i stimulation than SSc. That is not to say that MSc is not involved in the specific regeneration, there must be other factors guide motor neuron fiber directly or indirectly.