NT-4 Gene Expression of Male Wistar Rat’s Sciatic Nerve Fiber: The Effect of Decreased Activity on the Form of Spinal Nerve Ligation

Background & Objectives: Painful neuropathy is a state resulting from somatosensory disease or injury. Neurotrophins such as NT-4 are crucial for neural growth and development and protect the integrity of function and structure of nervous system. Paying heed to the importance of physical activity in neural plasticity, this study focuses on the investigation of chronic effect of decreased activity on the form of spinal nerve ligation on NT-4 gene expression of male Wistar rat’s sciatic nerve fiber. Materials & Methods: Ten adult male Wistar rats in the weight range of 250±30 gr were randomly divided into two groups, including one healthy control group (C) and one group with decreased physical activity (SNL). Over six weeks, neuropathic pain behavior tests were conducted continually in both groups. At the end of the sixth week, the changes in NT-4 gene expression in sciatic nerve were measured with Real time technique. Results: The behavioral tests demonstrated that spinal nerve ligation induced thermal hyperalgesia and mechanical allodynia in the SNL group. Decreased pain threshold was observed throughout the study period (p<0.05). Additionally, in comparison with the C group, NT-4 gene expression in sciatic nerve fiber was significantly higher in the SNL group (p<0.05). Conclusion: In the present study, it was discovered that the decreased activity in the form of SNL is associated with increased NT-4 gene expression in the experimental group. With respect to the physiologic functions of NT-4 in nervous system, this elevation is probably a mechanism for neurogenesis in the injured area, and based on the previous studies, it seems that the increased activity could enhance the increased NT-4 gene expression and accelerate neurogenesis.