Babaei-Balderlou Farrin, Zare Samad
Department of Biology, Faculty of Sciences, Urmia University, Urmia, Iran.
Vet Res Forum. 2012 Summer;3(3):187-92.
The aim of the present study was to evaluate the effect of melatonin as an antioxidant on spatial navigation memory in male diabetic rats. Thirty-two male white Wistar rats weighing 200 ± 20 g were divided into four groups, randomly: control, melatonin, diabetic and melatonin-treated diabetic. Experimental diabetes was induced by intraperitoneal injection of 50 mg kg(-1) streptozotocin. Melatonin was injected (10 mg kg(-1) day(-1), ip) for 2 weeks after 21 days of diabetes induction. At the end of administration period, the spatial navigation memory of rats was evaluated by cross-arm maze. In this study lipid peroxidation levels, glutathione-peroxidase and catalase activities were measured in hippocampus. Diabetes caused to significant decrease in alternation percent in the cross-arm maze, as a spatial memory index, compared to the control group (p < 0.05), whereas administration of melatonin prevented the spatial memory deficit in diabetic rats. Also melatonin injection significantly increased the spatial memory in intact animals compared to the control group (p < 0.05). Assessment of hippocampus homogenates indicated an increase in lipid peroxidation levels and a decrease in GSH-Px and CAT activities in the diabetic group compared to the control animals, while melatonin administration ameliorated these indices in diabetic rats. In conclusion, diabetes induction leads to debilitation of spatial navigation memory in rats, and the melatonin treatment improves the memory presumably through the reduction of oxidative stress in hippocampus of diabetic rats.
本研究的目的是评估褪黑素作为一种抗氧化剂对雄性糖尿病大鼠空间导航记忆的影响。将32只体重为200±20 g的雄性白色Wistar大鼠随机分为四组：对照组、褪黑素组、糖尿病组和褪黑素治疗糖尿病组。通过腹腔注射50 mg kg(-1)链脲佐菌素诱导实验性糖尿病。在糖尿病诱导21天后，注射褪黑素（10 mg kg(-1) 天(-1)，腹腔注射），持续2周。给药期结束时，通过十字臂迷宫评估大鼠的空间导航记忆。在本研究中，测量了海马体中的脂质过氧化水平、谷胱甘肽过氧化物酶和过氧化氢酶活性。与对照组相比，糖尿病导致十字臂迷宫中作为空间记忆指标的交替百分比显著降低（p < 0.05），而褪黑素给药可预防糖尿病大鼠的空间记忆缺陷。此外，与对照组相比，注射褪黑素显著提高了正常动物的空间记忆（p < 0.05）。海马体匀浆评估表明，与对照动物相比，糖尿病组的脂质过氧化水平升高，谷胱甘肽过氧化物酶和过氧化氢酶活性降低，而褪黑素给药改善了糖尿病大鼠的这些指标。总之，糖尿病诱导导致大鼠空间导航记忆减弱，褪黑素治疗可能通过降低糖尿病大鼠海马体中的氧化应激来改善记忆。
