雌激素对去卵巢沙土鼠脑缺血再灌注损伤后神经细胞凋亡的保护作用

Protective effects of estrogen on neural apoptosis after cerebral ischemia reperfusion in gerbils undergoing ovariectomy

目的:观察补充外源性雌激素对去卵巢沙土鼠脑缺血再灌注损伤后神经细胞凋亡的影响。方法:实验于2003-07／09在泰山医学院基础医学部机能学实验室进行。取雌性沙土鼠40只,随机分为假手术组、缺血再灌注组、去卵巢对照组和雌激素组4组,每组10只。①去卵巢对照组和雌激素组沙土鼠切除卵巢,其他两组仅打开腹腔不切除卵巢。②雌激素组沙土鼠切除卵巢 30 d后,肌肉注射雌二醇100μg/(kg·d),其余3组动物肌肉注射玉米油1 mL／(kg·d),共7 d。③末次给药30 min后,各组动物夹闭双侧颈总动脉7 min再灌注3 d制备脑缺血再灌注手术模型,假手术组不夹闭颈总动脉。④造模3 d后麻醉状态下处死动物取材,TUNEL法检测脑海马神经细胞凋亡密度,光、电镜观察脑海马CA1区神经细胞形态变化。结果:40只沙土鼠全部进入结果分析。①脑海马神经细胞凋亡细胞数: 缺血再灌注组和去卵巢对照组均高于假手术组[(59．9+2．6),(58．2±3．4), (25．5±4．1)个,P均<0．01],雌激素组低于缺血再灌注组和去卵巢对照组 [(40．6±3．5)个,P均<0．01],但仍高于假手术组。②光镜下脑海马CA1区神经细胞形态:缺血再灌注组、去卵巢对照组细胞排列稀疏、紊乱,细胞自溶,脱失明显,细胞及血管周围间隙扩大,细胞结构不清;雌激素组缺血性改变明显减轻。③电镜下脑海马CA1区神经细胞形态:缺血再灌注组、去卵巢对照组细胞外形不规则,线粒体肿胀,大部分膜崩解,嵴水肿明显;雌激素组神经细胞线粒体水肿明显变轻,但仍有部分膜崩解,核膜基本完整。结论:在缺乏雌激素的个体中补充雌激素能明显抑制细胞凋亡的发生, 对脑缺血再灌注损伤保护作用。

AIM： To observe the effects of supplemented exogenous estrogen on neural apoptosis in gerbil undergoing ovariectomy after cerebral ischemia reperfusion. METHODS： The experiment was conducted at the Function Lab, Department of Basic Medicine, Taishan Medical College between July and September 2003. Forty female gerbils were selected, and divided randomly into sham operation group, ischemia reperfusion group, ovariectomy control group and estrin group with 10 gerbils in each group. ① The ovaries of gerbils in the ovariectomy control group and estrin group were cut, and abdominal cavities of the gerbils in the other groups were opened without ovariectomy. ②After ovariectomy for 30 days, the gerbils in the estrin group were injected with 100μg/kg estradiol through muscles per day, and those, in the other three groups were injected with 1 mL/kg maize oil per day through muscles for 7 days. ③Thirty minutes after the last administration, common carotid artery at double side was closed by clip in rats of every group for 7 minutes, and reperfused for 3 days to make cerebral ischemia reperfusion models. The common carotid arteries of those in the sham operation group were not closed by clip. ④ After building models for 3 days, the materials were drawn after killing animals under drugged state. Density of the hippocampal neuroeyte apoptosis was studied through Tunel test. The neurocyte shapes in hippocampus CA1 were observed under the light and electronic microscope. RESULTS： Forty gerbils were all involved in the result analysis.①Number of hippocampal neurocyte apoptosis： it was higher in the ischemia reperfusion group and ovariectomy control group than that in the sham operation group [（59.9±2.6）,（58.2±3.4）, （25.5±4.1） piece, P〈0.01], and it was lower in the estrin group than that in the ischemia reperfusion group and ovariectomy control group [（40.6±3.5）,P〈 0.01], but still higher in the sham operation group. ②Neurocyts in hippocampus CA1 under the light microscope： In the ischemia reperfusion group and ovariectomy control group, the arranging sparsely and irregularly, and dissolving as well. The neurocyts and interstice surrounding capillaries were enlarged. Neurocyte structure was not clear. In the estrin group, ischemic injury of the neurocyte was significantly reduced. ③ Neuroeyts in hippoeampus CA I under the electron microscope： In both ischemia reperfusion and ovariectomy control group, the cell shapes were irregular, mitochondria swelling, mitochondria membrane seriously disintegrated and cristae obviously edema. In the estrin group, the neurocytes showed mitochondria edema mitigating significantly, a few mitochondria membrane disintegrated and nueleomembrane mainly integrated. CONCLUSION： Administering estrogen to an individual body lacking it can obviously inhibit apoptosis so as to protect the injury of cerebral ischemia reperfusion.