Exercise training attenuates acute hyperalgesia in streptozotocin-induced diabetic female rats

Abstract

OBJECTIVES:We investigated the effects of chronic (eight weeks) low- to moderate-intensity swimming training on thermal pain sensitivity in streptozotocin-induced diabetic female rats.METHODS:Female Wistar rats (n = 51) were divided into the following groups: trained streptozotocin-induced diabetic rats [hyperglycemic trained (HT)], sedentary streptozotocin-induced diabetic rats [hyperglycemic sedentary (HS)], normoglycemic trained rats (NT) and normoglycemic sedentary rats (NS). Diabetes was induced by a single injection of streptozotocin (50 mg/kg, i.p.). One day after the last exercise protocol (60 min/day, five days/week for eight weeks) in the trained groups or after water stress exposure (ten min/twice a week) in the sedentary groups, the rats were subjected to a hot plate test.RESULTS:After eight weeks of swimming training, streptozotocin-induced diabetic rats presented a significantly lower body mass (trained: 219.5±29 g, sedentary: 217.8±23 g) compared with the normoglycemic groups (trained: 271±24 g, sedentary: 275.7±32 g). Interestingly, we did not find differences in blood glucose levels (mg/dl) between the trained and sedentary groups of the hyperglycemic or normoglycemic rats (HT: 360.2±66.6, HS: 391.7±66.7, NT: 83.8±14.0, NS: 77.5±10.1). In the hot plate test, the rats from the HT group presented a significantly lower latency than the other rats (HT: 11.7±7.38 s, HS: 7.02±7.38 s, NT: 21.21±7.64 s, NS: 22.82±7.82 s).CONCLUSION:Low-to-moderate swimming training for a long duration reduces thermal hyperalgesia during a hot plate test in streptozotocin-induced diabetic female rats.

Prior voluntary wheel running attenuates neuropathic pain

“…Whether running began immediately after injury or once neuropathic pain was established did not influence the rate of recovery. The reversal of peripheral neuropathic pain supports similar studies that have used forced exercise paradigms, 1,7,12–15,34,42,54,60 but contrasts to a recent report wherein 2 weeks of voluntary wheel running did not reverse established allodynia. 56 This negative result may be due to the fact that this study terminated after 2 weeks of exercise, since reversal of allodynia was first emerging after 2 weeks of exercise in the present study.…”

“…1,6,7,12–15,18,31,34,42,54,60 Several studies have reported that neuroimmune signaling, processes that subserve neuropathic pain after nerve injury, 2,21 is suppressed in the neuraxis of rodents exercised after injury. For example, expression of activation markers for microglia (Iba1, CD11b) and astrocytes (GFAP) is decreased in the spinal dorsal horn, 1,6,15,31,42 while pro-inflammatory cytokines tumor necrosis factor and interleukin-1β (IL-1β) are downregulated in the brainstem and sciatic nerve.…”

Moderate exercise training attenuates inflammatory mediators in DRG of Type 1 diabetic rats

“…Exercise also attenuated the increased responsiveness of leukocytes in diabetic patients when compared to those of controls, thereby diminishing ROS release by neutrophils and macrophages (Hatanaka et al, 2006). It has been shown that swimming for a long duration reduces thermal hyperalgesia in STZinduced diabetic female rats (Rossi et al, 2011). Therefore, exercise or lifestyle intervention strategies that include an exercise component may even delay or protect against the development of diabetic peripheral nerve complications.…”

“…Previously, we have shown that the inflammatory mediators in the dorsal root ganglia are altered with the development of pain in Type 2 model of diabetes (Galloway and Chattopadhyay, 2013). Although earlier studies have demonstrated the effects of moderate to intense physical exercise on pain perception (Rossi et al, 2011), not many have shown the effects of moderate exercise that may change the endogenous opioid content as well as the levels of inflammation in DRG of Type 1 diabetic animals with painful neuropathy. Hyperglycemia causes p38 mitogen-activated protein (p38) kinase activation (Igarashi et al, 1999), which can be induced by changes in the release of proinflammatory cytokines.…”

Exercise-Induced Modulation of Pain in Adults With and Without Painful Diabetic Neuropathy

“…Results from several animal studies suggest that an exercise training program reduces behavioral symptoms of neuropathic pain and tactile sensitivity. 28, 37, 38, 40 In addition, one human study indicated improvements in neuropathic symptoms and cutaneous nerve fiber branching following an exercise training program. 20 …”