Neurobiology of Pain: 

How Oxidative Stress and Systemic Inflammation drive chronic pain

Oxidative stress and systemic inflammation contribute to chronic pain through bidirectional amplification mechanisms that establish central sensitization, peripheral nociceptor sensitization, and neuroinflammation—creating self-sustaining pain circuits.[1][2]

The first section is derived with AI assistance and digs deep into the mechanisms by which chronic pain, via peripheral and central sensitization are sustained by oxidative stress (OS) and systemic inflammation (SI).  Following this section is an overview of methods of combating OS, SI and Central sensitization.

 

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Definitions and Terms Related to Pain

 

Section  I

Oxidative Stress, Systemic Inflammation and Chronic Pain

Oxidative stress and systemic inflammation contribute to chronic pain through bidirectional amplification mechanisms that establish central sensitization, peripheral nociceptor sensitization, and neuroinflammation—creating self-sustaining pain circuits.[1][2]

Oxidative Stress Mechanisms

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) directly enhance neuroexcitability through multiple pathways. NADPH oxidase enzymes (particularly NOX2 and NOX4) generate superoxide in neurons, glial cells, and immune cells, which then activates transient receptor potential (TRP) channels on nociceptors, lowering their activation thresholds.[3][4] ROS also produce downstream oxidative products like 4-hydroxynonenal (4-HNE) and advanced oxidation protein products (AOPPs), which further amplify pain signaling through RAGE receptor activation and NF-κB pathway engagement.[5][6]

Mitochondrial dysfunction plays a central role—nerve injury and metabolic stress disrupt mitochondrial function, creating a vicious cycle where impaired mitochondria produce excess ROS while simultaneously reducing ATP availability in both peripheral sensory neurons and central neural cells.[7][8] This ATP depletion in the CNS contributes to generalized hypersensitivity and widespread pain, particularly evident in fibromyalgia and chronic fatigue syndrome.[7]  See: Mitochondrial Dysfunction

Inflammatory Mechanisms

Neuroinflammation drives central sensitization through glial cell activation. In the spinal dorsal horn and dorsal root ganglia, microglia and astrocytes respond to oxidative stress by releasing pro-inflammatory cytokines (IL-1β, TNFα), chemokines (CCL2), and brain-derived neurotrophic factor (BDNF), which enhance synaptic transmission and reduce inhibitory tone through KCC2 dysfunction.[1][9] This creates a state of heightened neuronal responsiveness that persists beyond the initial injury.

Peripheral immune cells, particularly monocytes/macrophages, contribute through CCL2/CCR2 signaling. CCL2-recruited macrophages generate ROS via NADPH oxidase, which directly induces hyperalgesia—this pathway is distinct from classical inflammatory pain and represents a specific oxidative-inflammatory mechanism.[5]

The Feed-Forward Loop

The critical pathophysiological feature is the reciprocal amplification between oxidative stress and inflammation.[3][2] ROS activate NF-κB and MAPK pathways in glial and immune cells, triggering cytokine release. These cytokines then stimulate further ROS production through NADPH oxidase activation, establishing a self-perpetuating cycle.[10] Additionally, oxidative stress induces cellular senescence and the senescence-associated secretory phenotype (SASP), which releases additional inflammatory mediators that maintain chronic neuroinflammation.[1]

Superoxide-induced pain specifically depends on TNFα/TNFR1 signaling, and blocking either pathway interrupts the cycle—demonstrating the interdependence of these mechanisms.[10] This oxidative-inflammatory circuit sustains both peripheral sensitization (ectopic firing, lowered nociceptor thresholds) and central sensitization (enhanced spinal cord excitability, reduced descending inhibition).[1][2]

Clinical Relevance

Elevated systemic oxidative stress markers (F2-isoprostanes, isofurans) correlate with characteristic features of dysfunctional chronic pain, including greater pain intensity, widespread pain distribution, catastrophizing, depression, and functional impairment.[11] Low-grade systemic inflammation may serve as both a predisposing and precipitating factor for chronic pain development and its psychological comorbidities.[12]

 

Section II

A Summary of clinical evidence on interventions that specifically target Oxidative Stress  (OS) and Systemic Inflammation (SI)

Clinical evidence shows that antioxidants and dietary interventions demonstrate modest-to-moderate efficacy in reducing chronic pain, particularly in fibromyalgia and neuropathic pain conditions.

Antioxidant Interventions

Fibromyalgia

A systematic review of antioxidant supplementation in fibromyalgia found that interventions lasting ≥6 weeks reduced pain in 80% of patients.[1] Coenzyme Q10 and vitamins showed the most consistent benefits, though effect sizes varied considerably across studies. Another review confirmed that antioxidants can diminish fibromyalgia symptoms through multiple mechanisms including hyperbaric oxygen therapy, dietary modifications, and physical activity.[2]

 

Neuropathic Pain

For diabetic peripheral neuropathy (DPN), alpha-lipoic acid, acetyl-L-carnitine, and vitamin D showed efficacy in reducing neuropathic pain.[3] However, for chemotherapy-induced peripheral neuropathy (CIPN), the evidence is less compelling—acetyl-L-carnitine was found potentially harmful, while N-acetyl-cysteine, L-carnosine, crocin, and magnesium warrant further investigation.[3] Vitamin C prophylaxis (500-1500 mg/day) shows promise for preventing complex regional pain syndrome type I (CRPS-I).[3]

 

Nrf2 Activators

Preclinical evidence strongly supports Nrf2 inducers as potent analgesics in various chronic pain models by alleviating ROS-associated pathological processes.[4] The polyphenolic fraction of bergamot (BPF) demonstrated ability to preserve SIRT1 activity, reduce oxidative stress markers (MDA, 8-OHdG), and alleviate hyperalgesia and allodynia in inflammatory pain models.[5] However, clinical translation remains limited.

Diets   

Mediterranean, vegetarian, and vegan diets show fair evidence for reducing musculoskeletal pain.[7] These plant-based diets rich in anti-inflammatory nutrients (fruits, vegetables, omega-3 fatty acids, antioxidants, fiber) lead to reductions in pain severity and interference.[8] Marine oils, omega-3 fatty acids, antioxidant-rich fruits, and turmeric may provide additional benefits.[9][7]

Caloric restriction may be effective for long-term pain management, while ketogenic diets may improve quality of life in chronic conditions, though consensus on intermittent fasting effects is lacking.[10]

 

Specialized Pro-Resolving Mediators

Exogenous specialized pro-resolving mediators (SPMs) ameliorate neuropathic pain pathophysiology in preclinical models by enhancing inflammation resolution and modulating oxidative stress.[11] Clinical trials in humans are needed. Unfortunately, these compounds are available only for research. Of interest, however, is that omega-3 fatty acids EPA and DHA function as dietary substrates (sources) for the body to manufacture, endogenous pro-resolving mediators.

 

NADPH Oxidase Inhibitors

Deletion or inhibition of NOX isoforms 2 and 4 produces beneficial effects in neuropathic pain models.[11] Isoform-specific NOX inhibitors represent promising therapeutic strategies, though clinical development remains in early stages.

Clinical Recommendations

Current evidence supports plant-based diets and select antioxidant supplements (particularly coenzyme Q10, alpha-lipoic acid, and vitamin D for specific neuropathic conditions) as adjunctive therapies for chronic pain management. The optimal duration appears to be ≥6 weeks for antioxidant interventions.[1]

Section  I References

How oxidative stress and systemic inflammation drive chronic pain

  1. Oxidative Stress, Inflammation, and Cellular Senescence in Neuropathic Pain: Mechanistic Crosstalk. Stojanovic B, Milivojcevic Bevc I, Dimitrijevic Stojanovic M, et al. Antioxidants (Basel, Switzerland). 2025;14(10):1166. doi:10.3390/antiox14101166.
  2. Nitroxidative Signaling Mechanisms in Pathological Pain. Grace PM, Gaudet AD, Staikopoulos V, et al. Trends in Neurosciences. 2016;39(12):862-879. doi:10.1016/j.tins.2016.10.003.
  3. Neuroinflammation, Oxidative Stress and Their Interplay in Neuropathic Pain: Focus on Specialized Pro-Resolving Mediators and NADPH Oxidase Inhibitors as Potential Therapeutic Strategies. Teixeira-Santos L, Albino-Teixeira A, Pinho D. Pharmacological Research. 2020;162:105280. doi:10.1016/j.phrs.2020.105280.
  4. NADPH Oxidases in Pain Processing. Kallenborn-Gerhardt W, Schröder K, Schmidtko A. Antioxidants (Basel, Switzerland). 2022;11(6):1162. doi:10.3390/antiox11061162.
  5. The Connection of Monocytes and Reactive Oxygen Species in Pain. Hackel D, Pflücke D, Neumann A, et al. PloS One. 2013;8(5):e63564. doi:10.1371/journal.pone.0063564.
  6. Accumulation of Advanced Oxidative Protein Products Exacerbate Satellite Glial Cells Activation and Neuropathic Pain. Tu C, Wang SC, Dai MX, et al. Molecular Medicine (Cambridge, Mass.). 2025;31(1):25. doi:10.1186/s10020-025-01076-x.
  7. The Role of Mitochondrial Dysfunctions Due to Oxidative and Nitrosative Stress in the Chronic Pain or Chronic Fatigue Syndromes and Fibromyalgia Patients: Peripheral and Central Mechanisms as Therapeutic Targets?. Meeus M, Nijs J, Hermans L, Goubert D, Calders P. Expert Opinion on Therapeutic Targets. 2013;17(9):1081-9. doi:10.1517/14728222.2013.818657.
  8. Neuropathic Pain: Delving Into the Oxidative Origin and the Possible Implication of Transient Receptor Potential Channels. Carrasco C, Naziroǧlu M, Rodríguez AB, Pariente JA. Frontiers in Physiology. 2018;9:95. doi:10.3389/fphys.2018.00095.
  9. Neuroinflammation and Central Sensitization in Chronic and Widespread Pain. Ji RR, Nackley A, Huh Y, Terrando N, Maixner W. Anesthesiology. 2018;129(2):343-366. doi:10.1097/ALN.0000000000002130.
  10. Superoxide Anion-Induced Pain and Inflammation Depends on TNFα/TNFR1 Signaling in Mice. Yamacita-Borin FY, Zarpelon AC, Pinho-Ribeiro FA, et al. Neuroscience Letters. 2015;605:53-8. doi:10.1016/j.neulet.2015.08.015.
  11. Oxidative Stress Is Associated With Characteristic Features of the Dysfunctional Chronic Pain Phenotype. Bruehl S, Milne G, Schildcrout J, et al. Pain. 2022;163(4):786-794. doi:10.1097/j.pain.0000000000002429.
  12. Does Low Grade Systemic Inflammation Have a Role in Chronic Pain?. Zhou WBS, Meng J, Zhang J. Frontiers in Molecular Neuroscience. 2021;14:785214. doi:10.3389/fnmol.2021.785214.

 

Section  II References

A Summary of clinical evidence on interventions that specifically target Oxidative Stress  (OS) and Systemic Inflammation (SI)

  1. Effects of Antioxidants on Pain Perception in Patients With Fibromyalgia-a Systematic Review. Fernández-Araque A, Verde Z, Torres-Ortega C, et al. Journal of Clinical Medicine. 2022;11(9):2462. doi:10.3390/jcm11092462.
  2. Oxidative Stress in Fibromyalgia: From Pathology to Treatment. Assavarittirong C, Samborski W, Grygiel-Górniak B. Oxidative Medicine and Cellular Longevity. 2022;2022:1582432. doi:10.1155/2022/1582432.
  3. The Role of Diet and Non-Pharmacologic Supplements in the Treatment of Chronic Neuropathic Pain: A Systematic Review. Frediani JK, Lal AA, Kim E, et al. Pain Practice : The Official Journal of World Institute of Pain. 2024;24(1):186-210. doi:10.1111/papr.13291.
  4. The Therapeutic Potential of Nrf2 Inducers in Chronic Pain: Evidence From Preclinical Studies. Zhou YQ, Mei W, Tian XB, et al. Pharmacology & Therapeutics. 2021;225:107846. doi:10.1016/j.pharmthera.2021.107846.
  5. SIRT1: A Likely Key for Future Therapeutic Strategies for Pain Management. Ilari S, Nucera S, Passacatini LC, et al. Pharmacological Research. 2025;213:107670. doi:10.1016/j.phrs.2025.107670.
  6. Alleviation of Pain, PAIN Interference, and Oxidative Stress by a Novel Combination of Hemp Oil, Calamari Oil, and Broccoli: A Randomized, Double-Blind, Placebo-Controlled Trial. Carlisle C, Polley K, Panda C, et al. Nutrients. 2023;15(12):2654. doi:10.3390/nu15122654.
  7. Diet Composition’s Effect on Chronic Musculoskeletal Pain: A Narrative Review. Kurapatti M, Carreira D. Pain Physician. 2023;26(7):527-534.
  8. Diet and Chronic Non-Cancer Pain: The State of the Art and Future Directions. Brain K, Burrows TL, Bruggink L, et al. Journal of Clinical Medicine. 2021;10(21):5203. doi:10.3390/jcm10215203.
  9. Does Diet Play a Role in Reducing Nociception Related to Inflammation and Chronic Pain?. Bjørklund G, Aaseth J, Doşa MD, et al. Nutrition (Burbank, Los Angeles County, Calif.). 2019;66:153-165. doi:10.1016/j.nut.2019.04.007.
  10. The Effectiveness of Intermittent Fasting, Time Restricted Feeding, Caloric Restriction, a Ketogenic Diet and the Mediterranean Diet as Part of the Treatment Plan to Improve Health and Chronic Musculoskeletal Pain: A Systematic Review. Cuevas-Cervera M, Perez-Montilla JJ, Gonzalez-Muñoz A, Garcia-Rios MC, Navarro-Ledesma S. International Journal of Environmental Research and Public Health. 2022;19(11):6698. doi:10.3390/ijerph19116698.
  11. Neuroinflammation, Oxidative Stress and Their Interplay in Neuropathic Pain: Focus on Specialized Pro-Resolving Mediators and NADPH Oxidase Inhibitors as Potential Therapeutic Strategies. Teixeira-Santos L, Albino-Teixeira A, Pinho D. Pharmacological Research. 2020;162:105280. doi:10.1016/j.phrs.2020.105280.

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