切除卵巢对大鼠学习记忆和海马雌激素受体α的影响及电针的干预作用

The effects of electro-acupuncture on learning, memory and the expression of the hippocampal estrogen receptor alpha in ovariectomized rats

目的研究电针对去卵巢大鼠行为学及海马区雌激素受体α(estrogen receptor alpha,ERα)蛋白和mRNA表达的影响。方法将40只雌性SD大鼠随机分为4组:假手术组、模型组、假电针组、电针组,各10只。采用卵巢切除大鼠模型,造成低雌激素记忆障碍,去势2周后进行电针刺激,连续治疗3个月。以Morris水迷宫测试空间学习记忆能力,酶联免疫吸附分析(enzyme-linked immunosorbent assay,ELISA)检测血清雌二醇(estradiol,E2)浓度,免疫印迹法(Western blot,WB)和实时荧光定量PCR分别检测海马区ERα蛋白和mRNA的相对表达量。结果模型组、假手术组、电针组和假电针组大鼠逃避潜伏期分别为(49.65±3.82)s、(15.26±3.37)s、(14.33±3.62)s、(25.46±2.87)s,游泳距离分别为(941.88±37.77)cm、(291.66±23.42)cm、(261.52±28.76)cm、(471.01±33.31)cm,跨越平台数分别为(2.35±0.44)、(8.94±0.91)、(8.53±0.83)、(3.64±0.88)次,血清E2浓度分别为(38.16±5.44)pg/mL、(65.13±7.72)pg/mL、(56.47±6.70)pg/mL、(49.29±5.90)pg/mL,海马ERa蛋白表达分别为(0.406±0.040)、(0.985±0.086)、(0.796±0.072)、(0.498±0.063),海马ERamRNA表达分别为(1.037±1.021)、(2.303±0.065)、(1.410±0.062)、(1.153±0.035),模型组较假手术组其逃避潜伏期和游泳距离延长,跨越平台数增加,血清E2浓度及海马ERa蛋白和mRNA表达均降低,电针组和假电针组均较模型组有所改善,但电针组改善更明显,上述差异均有统计学意义(均P<0.01)。结论电针能够提高去卵巢大鼠学习记忆能力,其机制可能通过升高体内雌激素浓度上调海马ERα蛋白和mRNA的表达有关。

Objective To investigate the effects of electro-acupuncture （EA） on the behavior and expression of the hippocampus ERa in ovariectomized rats. Methods Forty female SD rats were randomly divided into four groups： sham operation group, model group, sham EA group and EA group （10 per each group）. Animals were o- variectomized to induce low estrogen and memory impairment. Two weeks after ovariectomy, rats received EA for 3 months. Morris water maze was used to test spatial learning and memory capacity. Enzyme-hnked immuuosorbent as- say was used to detect serum levels of estradiol （E2） concentration. Western blot and real-time fluorescence quantita- tive PCR were used to detect the ERα protein and mRNA relative expression levels in the rat hippocampus, respectively. Results The escape latencies were （49.65 ± 3.82）s, （15.26 ± 3.37）s, （14.33 ± 3.62）s, （25.46 ± 2.87）s in model, sham, EA and sham EA groups; swimming distances were （941.88 ±37.77）cm, （291.66 ± 23.42）cm, （261.52 ± 28.76） cm and （471.01 ± 33.31） cm in model, sham, EA and sham EA groups; and the numbers of cross-platform were 2.35 ± 0.44, 8.94 ± 0.91, 8.53± 0.83, and 3.64 ± 0.88 in model, sham, EA and sham EA groups. Serum E2 concentrations were （38.16 ± 5.44）pg/mL, （65.13 ± 7.72）pg/mL, （56.47 ± 6.70）pg/mL, and （49.29 ± 5.90）pg/mL in model, sham, EA and sham EA groups. The hippocmpal ERa protein expression levels were 0.406 ± 0.040, 0.985 ± 0.086, 0.796 ± 0.072 and 0.498 ± 0.063 model, sham, EA and sham EA groups. The hippocampal ERa mRNA expression were 1.037 ± 1.021, 2.303 ± 0.065, 1.410 ± 0.062 and 1.153 ± 0.035 model, sham, EA and sham EA groups. Compared to the sham group, ovariectomy significantly increased the escape latency and swimming distance, decreased the numbers of cross-platform, and reduced the concentrations of serum E2 and the hippocampal ERa protein and mRNA expression levels. Both EA and Sham EA significantly improved all ovarieetomy-indueed impairments mentioned above. However, the improvements were more pronounced in EA group than in EA sham group （P 〈 0.01 ）. Conclusions EA can improve learning and memory in ovarieetomized rats probably through enhancement of estrogen eoneentration and the protein and mRNA expression of the hippocampal Erec