Elevated dietary omega-6 polyunsaturated fatty acids induce reversible peripheral nerve dysfunction that exacerbates comorbid pain conditions

摘要

Chronic pain is the leading cause of disability worldwide(1) and is commonly associated with comorbid disorders(2). However, the role of diet in chronic pain is poorly understood. Of particular interest is the Western-style diet, enriched with omega-6 polyunsaturated fatty acids (PUFAs) that accumulate in membrane phospholipids and oxidise into pronociceptive oxylipins(3,4). Here we report that mice administered an omega-6 PUFA-enriched diet develop persistent nociceptive hypersensitivities, spontaneously active and hyper-responsive glabrous afferent fibres and histologic markers of peripheral nerve damage reminiscent of a peripheral neuropathy. Linoleic and arachidonic acids accumulate in lumbar dorsal root ganglia, with increased liberation via elevated phospholipase (PLA)2 activity. Pharmacological and molecular inhibition of PLA2G7 or diet reversal with high levels of omega-3 PUFAs attenuate nociceptive behaviours, neurophysiologic abnormalities and afferent histopathology induced by high omega-6 intake. Additionally, omega-6 PUFA accumulation exacerbates allodynia observed in preclinical inflammatory and neuropathic pain models and is strongly correlated with multiple pain indices of clinical diabetic neuropathy. Collectively, these data reveal dietary enrichment with omega-6 PUFAs as a new aetiology of peripheral neuropathy and risk factor for chronic pain and implicate multiple therapeutic considerations for clinical pain management.