the anti-nociceptive effect of ellagic acid in streptozotocin-induced hyperglycemic rats by oxidative stress involvement

Background/aim: hyperalgesia is one of the current complications of diabetes mellitus that oxidative stress and inflammation have principal role in its development. ellagic acid (ea) as a herbal component, has some biological activities, including antioxidant and anti-inflammatory effects. this study was designed to evaluate the possible beneficial effect of ea on hyperalgesia in streptozotocin (stz)-induced diabetic rat.materials and methods: rats were divided into control(vehicle received), diabetic, ea (25, 50 mg/kg)-treated control and ea(25, 50 mg/kg)-treated diabetic groups. diabetes was induced by a single intraperitoneal (ip) injection of streptozotocin (stz) (60 mg/kg). ea was administered daily by oral gavage for 4 weeks. hyperalgesia was assessed using tail flick (tf) and hot plate (hp) tests. also, oxidative stress markers including malondialdehyde (mda), total oxidant status (tos) and total antioxidant capacity (tac) in the serum were evaluated.results: diabetic animals showed marked reductions in tf and hp latencies, elevation of serum mda level and tos and diminution of serum tac compared to controls significantly. treatment of diabetic rats with ea ameliorated reduction of tf latency at the dose of 25 mg/kg and hp latency at the dose of 50 mg/kg. furthermore ea significantly increased tac and decreased mda level at dose of 50 mg/kg and reduced tos at both doses in the serum of diabetic animals. in ea treated normal rats we could see no significant alterations in the parameters studied.4conclusion: these results displayed potent antinociceptive effect of ea in diabetic rats via attenuating oxidative stress. this proposes therapeutic potential of ea for damping diabetic hyperalgesia.