Effect of exercise on neurogenic inflammation in spinal cord of Type 1 diabetic rats.

Neuropathy is a long-standing and hard to treat complication of diabetes that interferes almost 25-30% of diabetic patients and impacts the quality of life of the patients. Unforeseen side effects, dependency and addiction made the existing medical treatments comparatively ineffective. A number of studies indicate that moderate physical activity provides health-related advantages. However, existing data do not confirm whether regular physical activity would reduce the amount of inflammation in the nervous system of the subjects with Type 1 diabetes. This study reveals the significance of exercise to alleviate inflammation in the spinal cord of the nervous system and preserve sensory nerve function in animals with Type 1 diabetes after 6 weeks of exercise paradigm. Streptozotocin-diabetic animals were placed in motorized running wheels for sixty minutes per day, for five days a week for 6 weeks starting at one week after diabetes. Emerging evidence suggests that the increases in inflammatory mediators play an important role in the development of sensory neuropathy. This study shows that moderate exercise can reduce the release of a number of proinflammatory cytokines in the dorsal horn (DH) of spinal cord, subsequently delaying the development of neuropathy along with an increase in the anti-inflammatory mediator IL10 in the DH. In general, this study indicates that exercise may provide an alternative to the treatment for sensory neuropathy in Type 1 diabetic subjects via reducing the use of medication and providing an easier way to manage neuropathy.

Viral vector mediated continuous expression of interleukin-10 in DRG alleviates pain in type 1 diabetic animals.

Painful diabetic neuropathy is a common and difficult to treat complication of diabetes. A growing body of evidence implicates the role of inflammatory mediators in the damage to the peripheral axons and in the pathogenesis of neuropathic pain. Increased expression of pro-inflammatory cytokines such as interleukin (IL)-1ß and tumor necrosis factor (TNF)-α in the peripheral nervous system suggests the possibility of change in pain perception in diabetes. In this study we investigated that continuous delivery of IL10 in the nerve fibers achieved by HSV vector mediated transduction of dorsal root ganglion (DRG) in animals with Type 1 diabetes, blocks the nociceptive and stress responses in the DRG neurons by reducing IL1ß expression along with inhibition of phosphorylation of p38 MAPK (mitogen-activated protein kinase) and protein kinase C (PKC). The continuous expression of IL10 also alters Toll like receptor (TLR)-4 expression in the DRG with increased expression of heat shock protein (HSP)-70 in conjunction with the reduction of pain. Taken together, this study suggests that macrophage activation in the peripheral nervous system may be involved in the pathogenesis of pain in Type 1 diabetes and therapeutic benefits of HSV mediated local expression of IL10 in the DRG with the reduction of a number of proinflammatory cytokines, subsequently inhibits the development of painful neuropathy along with a decrease in stress associated markers in the DRG. This basic and preclinical study provides an important evidence for a novel treatment strategy that could lead to a clinical trial for what is currently a treatment resistant complication of diabetes.