بررسی تغییرات فاکتور نروتروفیکی BDNF و گیرنده‌های آن (P75, TrK-B) پس از قطع عصب سیاتیک در نوزاد موش صحرایی

  Background & Objective : As apoptotic cell death plays an important role in natural development and many pathologic conditions such as cancer and neurodegenerative diseases, understanding of its molecular mechanisms can be useful in designing new therapeutic strategies. In present study following induction of apoptosis in spinal motoneurons, expression of neurotrophic factor BDNF, and its receptors TrkB and p75 has been investigated. Materials & Methods: In this study, twenty of three days old neonates of Sprague-Dawley rats were randomly divided into control and experimental groups. In all animals of experimental group the left sciatic nerve was transected in the mid-thigh level. 21 days following axotomy in both groups the animals were sacrificed and the L4-L6 spinal cord segments were used for cell count and immunohistochemical studies to assess the number of survived motoneurons and the expression of BDNF, TrkB and p75. In both groups the intact right side of spinal cord was considered as internal controls.  Results: Following transection of sciatic nerve, the number of related spinal motoneurons decreased by 58.89% and 55.84% compared to intact side and control group, respectively. The percentage of BDNF-positive and p75-positive motoneurons increased, but the percentage of TrkB-positive neurons has been decreased significantly.  Conclusion: The findings of this study indicates the different effects of BDNF on cell fate which are receptor-mediated, its binding to TrkB results in survival of neuron whereas its binding to p75 activates the apoptotic mechanism.