雌激素替代治疗对中老年卵巢切除大鼠海马CA1区有髓神经纤维的影响

Effects of estrogen replacement therapy on myelinated fibers in CA1 of hippocampus in middle-aged ovariectomized rats

目的研究雌激素替代治疗(estrogen replacement therapy,ERT)对中老年卵巢切除(ovariectomy,OVX)大鼠海马CA1区有髓神经纤维的影响。方法选取10月龄SD雌性大鼠切除双侧卵巢,术后1个月将大鼠随机分为雌激素替代治疗组(OVX+E2组)(10只)和安慰剂组(OVX+Veh组)(9只)。其中OVX+E2组给予连续4周的17β-雌二醇皮下注射,OVX+Veh组给予连续4周的安慰剂(芝麻油)皮下注射。应用Morris水迷宫对其空间记忆能力进行测试。应用冰冻切片技术、电镜技术及体视学方法对海马及其CA1区体积,有髓神经纤维总长度、总体积、髓鞘总体积、轴突总体积以及平均直径进行定量研究。结果 OVX+E2组大鼠Morris水迷宫的寻台潜伏期明显较OVX+Veh组短(P<0.05),但两组大鼠的海马及CA1区的平均体积没有显著性改变(P=0.100,P=0.366)。OVX+E2组有髓神经纤维总体积及髓鞘总体积均较OVX+Veh组显著增加(P=0.016,P=0.009)。结论雌激素替代治疗对中老年卵巢切除大鼠空间记忆能力及海马CA1区有髓神经纤维及其髓鞘结构均具有积极的保护作用。

Objective To determine the effects myelinated fibers in CA1 of the hippocampus in middle-old of estrogen replacement therapy （ERT） on the ovariectomized （OVX） rats. Methods Female rats of 10 months old were bilaterally ovariectomized, and then randomly divided into OVX ＋ E2 group and OVX ＋ Veh group. In 4 weeks after operation, 17β-estradiol （0.1 mg/mL, O. 25 μL/g） and placebo （ sesame oil, 0.25 μL/g） were subcutaneously injected respectively to OVX ＋ E2 rats and OVX ＋ Veh rats for 4 weeks. Then, Morris water maze was applied to test the spatial reference memory. Microscopy and stereology were applied to quantitatively investigate the total volumes of the hippocampus, the CA1 of the hippocampus, the total length, total volume, and mean diameter of the myelinated fibers and the myelin sheaths in the hippocampal CA1. Results The mean escape latency in spatial navigation of Morris water maze was significantly shortened in OVX ＋ E2 group from day 1 to 5 when compared to OVX ＋ Veh group （P 〈 0.05 ）. There was no significant difference in the hippocampal volume and CA1 volume between 2 groups （ P = 0. 100, P = 0. 366 ）. When compared to OVX ＋ Veh group, the total volume of the myelinated fibers and myelin sheaths in OVX ＋ E2 group were significantly increased （ P = 0. 016, P = 0.009 ） spatial memory and the structure of myelinated fibers aged ovariectomized rats ~ Conclusion Continuous 4 weeks＇ ERT protects the and myelin sheaths in the hippocampal CA1 of middleaged ovariectomized rats.