Iranian Journal of

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Background: Neuropathic pain is associated with a profound impact on quality of life and daily activity in patients and caused high medical costs. Because of the nerves destructive nature in this disease, the neurotrophins are high regarded for their possible effects on survival, growth and development and neuronal functions as a possible therapeutic strategy. So the aim of this study is investigation of the chronic effects of decreased activity in neuropathic pain form on the NFG gene expression in the sciatic nerve of Spinal nerve ligated rats.

Methods: Ten adult male Wistar rats in the weight range of 250±30 gr randomly were divided into two groups including healthy control (C), ligation sciatic nerve ligation. Over the six weeks neuropathic pain behavior tests were conducted continually in groups. In the end change of NGF gene expression in sciatic nerve was measured with Real time PCR technique and calculated using the ^{2-&Delta&DeltaCT} method.

Results: After 6 weeks, neuropathic pain behavior tests showed that pain threshold of thermal hyperalgesia and mechanical allodynia in the SNL group was significantly lower than the control group (P&le0.05). In addition, NGF gene expression in sciatic nerve ligation group compared to controls increased significantly (P&le0.05).

Conclusion: The findings of this study suggest that the development of neuropathic pain and decreased physical activity is associated with increased endogenous NGF. Although it is not clear that increase in NGF expression is due to the nature of neuropathic pain or nerve damage, it is clear that excessive expression of NGF is associated with neuropathic pain.

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Background: Dysfunction of Schwann cells by diabetes has far-reaching consequences for the structure and function of peripheral nerves. The aim of the present study was to evaluate the effect of aerobic exercise on the Nrg1 / ErbB2 signaling pathway in male rats with diabetic neuropathic pain.
Methods: Twenty-four 8-week-old male Wistar rats (weight range 204 ± 11.3 g) were randomly divided into three groups (n = 8) including: Diabetic neuropathy (50 mg / kg streptozotocin injection), Diabetic neuropathy Exercise (30 minutes exercise aerobics intensity 15 m/min, 5 days per week for 6 weeks), and healthy controls. After confirmation of diabetic neuropathic pain by behavioral tests, aerobic exercise protocol was performed. The expression of Nrg1 / ErbB2 genes was measured by real-time technique. One-way analysis of variance and Tukey's post hoc test were used for statistical analysis.  
Results: Aerobic exercise reduced the nervous system's sensitivity to thermal hyperalgesia and mechanical allodynia. Induction of diabetes significantly reduced Nrg1 and ErbB2 gene expression. There was also a significant increase in the expression of the above genes in the exercise group compared to the diabetic neuropathy group (P<0.05).
Conclusion: It seems that aerobic exercise is effective in increasing the nerve repair process by activating growth signaling pathways in Schwann cells. It is recommended that aerobic exercise be used for diabetics to reduce neuropathic pain.