title: Curcumin attenuates diabetic neuropathic pain by downregulating TNF-α in a rat model.
abstract: The mechanisms involved in diabetic neuropathic pain are complex and involve peripheral and central pathophysiological phenomena. Proinflammatory tumour necrosis factor α (TNF-α) and TNF-α receptor 1, which are markers of inflammation, contribute to neuropathic pain. The purpose of this experimental study was to evaluate the effect of curcumin on diabetic pain in rats. We tested 24 rats with diabetes induced by a single intraperitoneal injection of streptozotocin and 24 healthy control rats. Twelve rats in each group received 60 mg/kg oral curcumin daily for 28 days, and the other 12 received vehicle. On days 7, 14, 21, and 28, we tested mechanical allodynia with von Frey hairs and thermal hyperalgesia with radiant heat. Markers of inflammation in the spinal cord dorsal horn on day 28 were estimated with a commercial assay and Western blot analysis. Compared to control rats, diabetic rats exhibited increased mean plasma glucose concentration, decreased mean body weight, and significant pain hypersensitivity, as evidenced by decreased paw withdrawal threshold to von Frey hairs and decreased paw withdrawal latency to heat. Curcumin significantly attenuated the diabetes-induced allodynia and hyperalgesia and reduced the expression of both TNF-α and TNF-α receptor 1. Curcumin seems to relieve diabetic hyperalgesia, possibly through an inhibitory action on TNF-α and TNF-α receptor 1.
authors.affiliation: Department of air logistics, the 463 Hospital of PLA, Shenyang 110042, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: De-bao
authors.initials: DB
authors.lastname: Liu
authors.forename: Hai-ying
authors.initials: HY
authors.lastname: Liu
authors.forename: Wu-gang
authors.initials: WG
authors.lastname: Hou
authors.forename: Yu-shu
authors.initials: YS
authors.lastname: Dong
mesh_terms: D000818:Animals; D001786:Blood Glucose; D003474:Curcumin / Q000008:administration & dosage*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D003929:Diabetic Neuropathies / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D004195:Disease Models, Animal; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006930:Hyperalgesia / Q000378:metabolism / Q000473:pathology; D008297:Male; D009437:Neuralgia / Q000097:blood / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D014409:Tumor Necrosis Factor-alpha; D003474:Curcumin
keywords: curcumin; diabetic neuropathic pain; hyperalgesia; tumour necrosis factor α; tumour necrosis factor α receptor 1.