Search

Introduction: Some antidepressants are effective for treating neuropathic pain independent of any effect on depression. Selective serotonin reuptake inhibitors (SSRIs) are one of the potential agents to treat neuropathic pain. The aims of this study were to compare the effects of SSRI and non-steroidal anti-inflammatory drugs (NSAIDs) on pain-related behavior and expression of cytokines in a rat model of neuropathic pain. Materials and methods: Spinal surgery was performed to apply nucleus pulposus (NP) to the dorsal root ganglion (DRG). NP animals were treated with saline (NP + S), meloxicam (NP + M), or low-dose or high-dose paroxetine (NP + PL and NP + PH), respectively. Behavioral testing was performed to investigate the mechanical withdrawal thresholds. The numbers of TNF-immunoreactive (IR) neurons in the DRG and of Iba1-IR microglia in the spinal cord (SC) were evaluated using immunohistochemistry. Expression of TNF in the DRG was examined using Western blots. Results: The thresholds on days 14, 21, and 28 were higher in the drug-treated animals than in the NP + S group ( p < 0.05). The number of TNF-IR neurons in DRGs from the NP + M group increased on day 2 and decreased on day 7, and TNF expression in DRGs was significantly higher in the NP + S group than in the NP + M group on days 7, 14. The number of Iba1-IR microglia in the SC was significantly higher in the NP + S group than in the NP + M, NP + PL, and NP + PH groups on days 7 and 14. Conclusion: An antidepressant might be a potential agent to treat lumbar disc herniation as well as NSAIDs. [ABSTRACT FROM AUTHOR]

Study Design: A controlled, interventional animal study.Objective: The aim of this study was to evaluate the effect of diabetes mellitus (DM) on radiculopathy due to lumbar disc herniation (LDH), by investigating pain-related behavior and the expression of tumor necrosis factor-alpha (TNF-α) and growth-associated protein 43 (GAP43) in type 2 diabetic rats following application of nucleus pulposus (NP) to the dorsal root ganglion (DRG).Summary Of Background Data: Previous clinical studies suggested negative effects of DM on radiculopathy due to LDH, and that inflammation and nerve regeneration could interact with DM and radiculopathy.Methods: We applied autologous NP to the left L5 DRG of adult male Wistar rats and Goto-Kakizaki rats. Behavioral testing measured the mechanical withdrawal threshold of rats. We immunohistochemically evaluated the localization of ionized calcium-binding adapter molecule-1 (Iba-1), receptor of advanced glycation end products (RAGE), and TNF-α in DRGs. TNF-α and GAP43 expression levels in DRG were determined by quantitative real-time PCR and western blotting.Results: The mechanical withdrawal threshold significantly declined in the non-DM NP group compared with the non-DM sham group for 28 days, whereas the decline in threshold extended to 35 days in the DM NP group compared with the DM sham group. RAGE and TNF-α expression in DRGs was colocalized in Iba-1 positive cells. The non-DM NP rats had higher TNF-α protein expression levels versus the non-DM sham rats on day 7, and the DM NP group had higher levels versus the DM sham group on days 7 and 14. The non-DM NP group had higher GAP43 mRNA expression than the non-DM sham group for 28 days, while the DM NP group had a higher level than the DM sham group for 35 days.Conclusion: DM prolongs the pain-related behavior caused by NP. The prolonged inflammation and nerve regeneration could elucidate the pathogenesis of continuous pain of radiculopathy initiated by LDH.Level Of Evidence: N /A. [ABSTRACT FROM AUTHOR]

The article presents a study on the interaction of 5-hydroxytryptamine (5-HT) with tumor necrosis factor (TNF) for pain related behavior in a model of rat lumbar disc herniation (LDH). There were six groups of adult female Sprague-Dawley rats. It was found that 5-HT and TNF both induce pain-related behavior and interact with one another to prolong pain-related behavior in the model.

The article presents a study which observes the reaction of glial cells and endoneural macrophages positioned in the dorsal root ganglion in rats. It states that activated satellite glial cells expressed glial cell-line derived neurotrophic factor (GDNF) which expression thereof was significantly increased and persisted for 28 days. Results show that mechanical withdrawal threshold was significantly decreased for 28 days.