香芹酚对毒死蜱诱导的大鼠脑损伤保护作用研究

Protective effect of carvacrol on chlorpyrifos-induced brain injury in rats

目的研究香芹酚(carvacrol,CA)对毒死蜱(chlorpyrifos,CPF)诱导的大鼠脑损伤保护作用及作用机制的初步探讨。方法将70只SD大鼠随机分为对照组、CPF染毒组、依达拉奉干预组、解磷定干预组、低中高3种不同剂量CA干预组(12.5、25和50 mg/kg),皮下注射含CPF 18 mg/kg橄榄油溶液建立脑损伤模型,1 h后再分别给予依达拉奉、解磷定、低中高剂量CA处理,连续28 d。通过检测血清中乙酰胆碱酯酶(acetylcholinesterase,AChE)活性判断造模情况;通过Morris水迷宫和矿场实验测试大鼠学习记忆和自主探索能力。比较血清和脑组织丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)活力衡量氧化应激水平;通过Nissl染色观察大鼠海马体DG区神经元胞体中Nissl小体数量;采用免疫组织化学测定Nrf2蛋白的表达,检测脑组织Na^(+)-K^(+)-ATP酶、活性氧(reactive oxygen species,ROS)水平判断线粒体损伤情况。结果与对照组相比,CPF损伤组AChE活性明显下降(F=260.00,P<0.01);与模型组相比,经CA给药后,大鼠在矿场实验中穿越中心次数明显增加(F=9.79,P<0.01),运动距离明显缩短(F=3.40,P<0.01);在Morris水迷宫实验中逃避潜伏期明显缩短(F=43.68,P<0.01),穿越平台次数明显增加(F=15.77,P<0.01)。Nissl染色中,CA给药后神经细胞相比CPF损伤组明显增加(F=45.36,P<0.01)。血清中SOD和GSH-Px活性明显升高(F=15.08,F=20.72,P<0.01),MDA水平明显降低(F=27.21,P<0.01);脑组织中SOD和GSH-Px活性明显升高(F=5.88,F=1.81,P<0.01),ROS和MDA水平明显降低(F=13.95,F=5.06,P<0.01),Na^(+)-K^(+)-ATP酶活力明显升高(F=6.77,P<0.01)。免疫组化结果提示,Nrf2蛋白质含量较Model组明显增加(F=2.10,P<0.01)。结论CA可用于改善CPF诱导的大鼠脑损伤,其机制可能通过激活Nrf2信号通路发挥抗氧化作用。

Objective To investigate the protective effect of carvacrol on chlorpyrifos-induced brain injury in rats and its mechanism.Methods A total of 70 SD rats were randomly divided into control group,chlorpyrifos group,edaravone group,pralidoxime chloride group,three different doses of carvacrol administration groups(12.5 mg/kg,25 mg/kg,50 mg/kg).The brain injury model was established by subcutaneous injection of 18 mg/kg olive oil solution containing chlorpyrifos.And then treated with edaravone,pralidoxime chloride,low,medium and high doses of carvacrol 1 hour later for 28 consecutive days.The AChE activity in serum was detected to determine the modeling situation.The learning and memory ability of rats were tested by open field and water maze tests.The activities of MDA,SOD and GSH-Px in serum and brain tissue were compared to measure the oxidative stress level.Nissl staining was used to observe the number of Nissl bodies in neurons in hippocampus DG region of rats.The expression of Nrf2 protein was determined by immunohistochemistry,and the levels of Na^(+)-K^(+)-ATPase and ROS in brain tissue were detected to determine the mitochondrial damage.Results Compared with the Control group,the AChE activity in the chlorpyrifos injury group was statistically decreased(F=260.00,P<0.01).Compared with Model group,after carvacrol administration,the times of enter the center in the open field was statistically increased(F=9.79,P<0.01),and the total movement distance was statistically improved(F=3.40,P<0.01).In Morris water maze experiment,the escape latency was statistically shortened(F=43.68,P<0.01),and the number of crossing platforms was statistically increased(F=15.77,P<0.01).In Nissl staining,the number of nerve cells increased statistically after carvaxol administration compared with chlorpyrifos injury group(F=45.36,P<0.01).The activities of SOD and GSH-Px in serum were statistically increased(F=15.08,F=20.72,P<0.01),while the level of MDA was statistically decreased(F=27.21,P<0.01).The activities of SOD and GSH-Px in brain tissue were statistically increased(F=5.88,F=1.81,P<0.01),the levels of ROS and MDA were statistically decreased(F=13.95,F=5.06,P<0.01),and the activity of Na^(+)-K^(+)-ATPase was statistically increased(F=6.77,P<0.01).Immunohistochemical result showed that the protein content of Nrf2 was statistically higher than that of Model group(F=2.10,P<0.01).Conclusion Carvacrol alleviates chlorpyrifos induced brain injury in rats,and its mechanism may play an antioxidant role through activating Nrf2 signaling pathway.