Role of nicotinamide adenine dinucleotide phosphate oxidase in spinal cord in maintenance of diabetic neuropathic pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) in the spinal cord in the maintenance of diabetic neuropathic pain in rats.Methods Pathogenfree male Sprague-Dawley rats,aged 2 months,weighing 180-220 g,were used in the study.Diabetes mellitus was induced by intraperitoneal streptozotocin (STZ) 60mg/kg and confirmed by blood glucose ＞ 16.7 mmol/L at 72 h after STZ injection.Twenty diabetic rats were randomly allocated to diabetic neuropathic pain group (DN group,n =10) and apocynin (specific NADPH oxidase inhibitor) group (A group,n =10).Another 10 agematched normal rats served as control group (C group,n =10).Twenty-eight days after STZ injection,apyconin 5 mg/kg was injected intraperitoneally once a day for 7 consecutive days in A group.Paw withdrawal threshold to yon Frey filament stimulation (PWT) was measured before STZ injection (T1) and at 7,14,21,28 and 35 days after STZ injection (T2-6).The rats were sacrificed after PWT was measured at T6 and L4.5 segments of the spinal cord were removed for determination of NADPH oxidase subunits gp91phox and p47phox expression,MAD content and SOD activity.Results Compared with C group,PWT was significantly decreased at T3-5,gp91phox and p47phox expression was up-regulated,MAD content was increased,and SOD activity was decreased in DN and A groups.Compared with DN group,PWT was significantly increased at T6,gp91phox and p47phox expression was downregulated,MAD content was decreased,and SOD activity was increased in A group.Conclusion NADPH oxidase in the spinal cord is involved in the maintenance of diabetic neuropathic pain in rats.