石榴汁对慢性脑低灌注大鼠认知行为的影响及其作用机制研究

Study of influence of chronic cerebral hypoperfusion on cognitive function and mechanisms in rats of pomegranate juice

目的：探讨石榴汁对慢性脑低灌注大鼠认知行为的影响及其作用机制。方法选取48只健康雄性Wistar大鼠，随机分为3组，假手术组（ sham operation，SO）、大鼠双侧颈总动脉持久性结扎（ permanent bilateral commancarotid artery occlusion or two－vessel occlusion，2VO）组、石榴汁组。采用永久性双侧颈总动脉结扎术制备慢性脑低灌注大鼠模型。术后1周开始给予干预，前2组用糖水灌胃（每100 mL糖水含蔗糖25 g，葡萄糖2 g，果糖2 g），石榴汁组用石榴汁（多酚含量2．4～4．8 mg／mL）灌胃，均2 mL／d，共7周。术后第8周用Morris水迷宫检测3组大鼠在学习方面的认知行为能力，连续检测5 d；间隔1 d后用空间探索试验的目标象限游泳时间检测3组大鼠记忆方面的认知行为能力；用免疫组织化学方法检测3组大鼠皮层及海马CA1区8－羟基脱氧鸟苷（8－hydroxy－2 deoxyguanosine，8－OHDG）、4－羟壬烯醛（4－hydroxynonenal，4－HNE）的表达；观察石榴汁是否能改善慢性脑低灌注大鼠学习、记忆能力的作用，是否具有抗氧化应激损伤作用。结果在第4天和第5天，假手术组大鼠找到平台时间最短，2VO组时间最长，3组间比较差异有统计学意义（P＜0．01）；3组大鼠在目标象限出现时间假手术组最长（10．05±1．688） s，2VO组时间最短（6．343±1．220）s，且差异有统计学意义（ P＜0．05）。3组大鼠皮质与海马CA1区4HNE、8－OHdG的阳性细胞的积分光密度值（ integral optical density，IOD）以假手术组最低，2VO组最高，差异有统计学意义（P＜0．05）。石榴汁干预后，大鼠的皮质与海马CA1区的8－OHdG、4－HNE的表达明显减少（P＜0．05）。结论慢性脑低灌注可以引起氧化应激性损伤，石榴汁可以改善慢性脑低灌大鼠的学习与记忆能力，减少8－OHdG和4－HNE表达，可能通过抗氧化应激途径发挥脑保护功能。

Objective To explore the influence of pomegranate juice on cognitive behavior of chroniccerebral hypoperfusion in rats and its mechanism.Methods 48 healthy male Wistar rats were selected and randomly divided into 3 groups, sham operation group （SO）, permanent bilateral persistence commancarotid artery occlusion or two-vesselocclusion （2VO） group, pomegranate juice group.Chronic cerebral hypoperfusion model was prepared in rats by permanent bilateral common carotid artery ligation.Given the intervention after operation 1 weeks, before the 2 groups were given by sugar water intragastric （ every 100 mL syrup containing 25 g,sucrose 2 g, fructose glucose 2 g） with pomegranate juice, pomegranate juice group （ polyphenol content of 2.4-4.8 mg/mL） were given by gavage,2 mL/d, a total of 7 weeks.8 th weeks after surgery, cognitive behavior ability of 3 groups was tested by space exploration target quadrant swimming time after an interval of 1day;CA1 region of 8-hydroxy deoxyguanosine （8-OHdG）, 4-hydroxyl nonenal （ 4-HNE ） expression of 3 groups in cortex and hippocampus detected by immunohistochemical method; observed whether it could improve the chronic cerebral hypoperfusion in rats learning, memory ability, or had antioxidative stress injury.Results On the 4th day and 5th day, the time of rats in SO to find the platform and the shortest time, group 2VO for the longest time, compared with statistical significance between the three groups （P〈0.01）; the 3 groups of rats in the target quadrant emergence time in sham operation group, the longest （10.05＋1.688）s, 2VO group has the shortest time （6.343 ±1.220） s, and there was statistical significance （P〈0.05）.The integral optical density of positive cells in 3 groups of rats cortex and hippocampal CA1 region of 4HNE, the value of the 8-OHdG IOD is the lowest in the sham operation group, 2VO group was the highest, with statistical significance.Pomegranate juice intervention, cortex of rats and hippocampal CA1 region of 8-OHdG, 4-HNE decreased significantly （ P 〈0.05）.Conclusion Chronic cerebral hypoperfusion may cause oxidative stress injury, pomegranate juice can improve the low irrigation learning and memory ability of rats with chronic cerebral, decrease 8-OHdG and 4-HNE expression may play a protective function through antioxidative stressnbsp;pathway.