Exercise alleviates hypoalgesia and increases the level of calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats

Abstract

OBJECTIVE:The aim of this study was to evaluate the effects of treadmill training on nociceptive sensitivity and immunoreactivity to calcitonin gene-related peptide in the dorsal horn of the spinal cord of diabetic rats.METHODS:Male Wistar rats were divided into three groups: control, diabetic and trained diabetic. Treadmill training was performed for 8 weeks. The blood glucose concentrations and body weight were evaluated 48 h after diabetes induction and every 30 days thereafter. The nociceptive sensitivity was evaluated using the tail-flick apparatus. The animals were then transcardially perfused, and the spinal cords were post-fixed, cryoprotected and sectioned in a cryostat. Immunohistochemistry for calcitonin gene-related peptide analysis was performed on the dorsal horn of the spinal cord.RESULTS:The nociceptive sensitivity analysis revealed that, compared with the control and trained diabetic animals, the latency to tail deflection on the apparatus was longer for the diabetic animals. Optical densitometry demonstrated decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord in diabetic animals, which was reversed by treadmill training.CONCLUSION:We concluded that treadmill training can alleviate nociceptive hypoalgesia and reverse decreased calcitonin gene-related peptide immunoreactivity in the dorsal horn of the spinal cord of diabetic animals without pharmacological treatment.

Mechanisms of exercise for diabetic neuropathic pain

“…Meanwhile, the immunohistochemical procedure and optical densitometry were performed to measure the level and intensity of CGRP. The results showed that exercise reduced the hyperalgesia and reversed the diabetes-induced decrease in CGRP in the DRG levels of diabetic rats ( Nascimento et al, 2012 ). Therefore, the exercise mechanism for nociceptive hyperalgesia may be increase in CGRP, which reverses the pancreatic β-cell death induced by oxidative and ER stresses through ASK1, p38 MARK, and ERK1/2.…”

“…Therefore, the mechanism of apoptosis associated with CGRP is involved in the pathological mechanism of DNP. An STZ injection-induced diabetic rat model was established by Nascimento et al (2012) to research on the role of exercise in DNP and CGRP levels in DRG. A tail-flick apparatus was used to assess nociceptive injury changes.…”

Diabetic Neuropathic Pain: Directions for Exploring Treatments

“…Thus, these studies implied that patients with DNP, by performing proper exercises, could have a better internal glucose level control. Treadmill exercise in rat models with DNP was also found to be beneficial in relieving DNP by increasing NO synthesis [ 71 ] and regulating apoptosis [ 72 ], etc.…”