去卵巢后雌性大鼠下丘脑视前区NOS阳性神经元形态学和突触素表达的变化

目的：为解释围绝经期的精神、神经症状提供实验依据。方法：采用免疫细胞化学方法显示去卵巢雌性大鼠下丘脑视前内侧区(MPA)和视前外侧区(LPA)内NOS阳性神经元,形态学改变以及突触素表达。结果：(1)去卵巢组和对照组大鼠的视前内、外区内可见大量NOS阳性神经元;(2)去卵巢动物的下丘脑内NOS阳性神经元突起长度比对照组的明显变短,分支明显变少;(3)去卵巢组动物下丘脑内突触素表达比对照组的明显减少。结论：大鼠去卵巢后,由于雌激素分泌减少,导致了NOS阳性神经元的突起减少和突触减少,结果NO介导的神经元信号传导失常,这些变化可能是引发围绝经期的精神、神经症状的原因之一。     

左旋18-甲基炔诺酮对大鼠下丘脑GnRH神经元的影响

目的：观察孕激素类避孕药—左旋18-甲基炔诺酮(LNG)对大鼠下丘脑GnRH神经元的影响。方法：正常雌性大鼠分为长期给药组(灌服LNG90d)和停药组(停药后正常喂养20d)。免疫组织化学方法显示下丘脑GnRH阳性神经元。结果：长期给药组与对照组相比斜角带(db)、视前区(MPA)内GnRH阳性神经元构成比发生改变,棘型神经元减少,阳性神经元光密度减低,阳性纤维膨体密度降低,正中隆起(ME)处阳性纤维密度增加。停药后基本恢复正常。结论：从形态学上证实LNG作用于下丘脑水平;停药后GnRH阳性神经元形态学变化可恢复正常,表明LNG具有高效安全性。     

外源性雌激素对去势后大鼠下丘脑视上核一氧化氮合酶阳性神经元分布的影响

目的观察外源性雌激素对去势后雌性大鼠下丘脑视上核(SON)一氧化氮合酶(NOS)阳性神经元分布的影响。方法选用2～3月龄、健康未交配的雌性大鼠40只;动物分组如下:对照组大鼠20只,分为正常对照组(n=10)和实验对照组(卵巢切除术后,n=10)。实验组(即卵巢切除术后肌肉注射雌激素组)20只,造模成功后,分别于术后40d(即给药一个月)和术后70d(即给药两个月)陆续灌注取材。采用SABC法在光学显微镜下对下丘脑视上核内NOS阳性神经元进行形态学观察和细胞计数,采用图像分析系统测定NOS阳性神经元内免疫反应产物的平均灰度值。结果卵巢切除术后对照组大鼠下丘脑视上核NOS阳性神经元的密度明显增高,细胞比正常对照组有所增大(P0.05)。去势后补充雌激素1个月组的大鼠与正常对照组和卵巢切除组相比较,视上核内NOS阳性神经元的密度及形态均无明显改变(P0.05)。去势后补充雌激素两个月组与实验对照组相比较,无论NOS阳性神经元的密度还是阳性神经元胞体的大小均显著下降(P0.05),细胞着色变浅。结论外源性雌激素可能影响去势雌性大鼠下丘脑视上核NOS阳性神经元的分布和表达。     

雄性大鼠去势后下丘脑NOS神经元的分布

目的：探讨雄性大鼠去势术后下丘脑内一氧化氮合酶（NOS）阳性神经元的改变。方法：发育期雄性SD大鼠,分三组：假手术组,去势组和去势＋睾酮替代治疗组,利用黄递酶组织化学染色方法观察与比较各组大鼠与生殖相关各下丘脑核团内NOS神经元数目与密度,结果：在下丘脑的视前内侧核,视前室周核,正中隆起,弓状核均可见到NOS阳性标记细胞。去势术后视前内侧核内NOS神经元数目及密度降低,睾酮替代治疗可逆转,结论：一氧化氮在雄激素对下丘脑的反馈调节中起重要的介导作用。     

大鼠下丘脑一氧化氮合酶（NOS）阳性神经元的分布

观察大鼠下丘脑各核团NOS阳性神经元的分布。采用还原型尼克酰胺腺嘌呤二核苷酸脱氢酶（NADPH－d）法，结果显示，大量NOS阳性神经元见于下丘脑外侧区、视上核（SO）和室旁核（Pa）；出现较多NOS阳性神经元的部位是视前大细胞核，见到少量NOS阳性神经元的部位是室周核、视前内侧区、视前外侧区和下丘脑前区。结论：NOS阳性神经元分布于下丘脑的许多核团。     

高原低氧对大鼠下丘脑谷氨酸、天门冬氨酸和NOS的影响

目的:观察高原低氧大鼠下丘脑谷氨酸(Glu)、天门冬氨酸(Asp)和一氧化氮合酶(NOS)的变化。方法:应用氨基酸测定和NADPH-d组化法,检测高原低氧模型大鼠下丘脑Glu、Asp含量和NADPH-d阳性神经元的数量。结果:高原低氧大鼠下丘脑Glu、Asp含量明显增多,室旁核、视上核可见密集深染的NADPH-d阳性神经元;用NMDA受体拮抗剂氯氨酮(Ketamine)和AP-V对高原低氧大鼠进行预处理后置于低压氧舱,观察到大鼠下丘脑室旁核、视上核NADPH-d阳性神经元数明显少于相应时间的高原低氧组(P＜0.01)。结论:NMDA受体可能参与了高原低氧引起的下丘脑NOS的表达。     

雌性大鼠下丘脑5-羟色胺1A和2A受体亚型的定位分布

本研究应用免疫细胞化学技术观察了雌性成年SD大鼠下丘脑内5-HT1A受体亚型(5-HT1AR)和5-HT2AR免疫阳性结构的分布。结果显示:5-HT1AR免疫阳性神经元在视前区大细胞核、视前室周核、视上核和下丘脑外侧前核等核团内密集分布。在内侧视前核、外侧视前区、下丘脑室周核、下丘脑外侧区、背内侧核、腹内侧核、结节核、结节乳头体核、乳头体内侧核和乳头体外侧核等结构内也有较多的分布;而在正中视前核、视交叉上核、下丘脑室旁核、下丘脑背侧核、弓状核、乳头体上核和乳头体前核等部位有散在的分布。与5-HT1AR不同,5-HT2AR免疫阳性反应产物主要见于纤维和终末,阳性胞体少且染色淡。5-HT2AR阳性胞体见于下丘脑室旁核、视上核、腹内侧核、结节核、视前内侧区、外侧区、外侧前核、下丘脑背内侧核等处。另外,在视前区前内侧视前核、视交叉上核背侧和外侧可见围绕血管分布、密集成团簇状、带有大小不同膨体的阳性神经纤维缠结。本文结果提示5-HT1AR阳性结构广泛地分布于大鼠下丘脑,而5-HT2AR在下丘脑分布较为局限。二者不同的分布特点,提示它们可能介导5-HT在下丘脑的不同生理功能。     

精氨酸加压素阳性神经元在大鼠下丘脑的定位

目的:观察大鼠精氨酸加压素(AVP)及其mRNA阳性神经元在下丘脑的分布和形态特征。方法:以尼氏染色作参照,运用免疫组化和原位杂交观察AVP及其mRNA在下丘脑的表达。结果:下丘脑AVP及其mRNA阳性的神经元由吻侧到尾侧依次出现于视上核,视上核和视交叉上核,视上核、视交叉上核和室旁核,视上核和室旁核及视上核、下丘脑前核和室旁核。AVP及其mRNA阳性神经元仅占据视上核背内侧;在第三脑室室管膜膜内或膜下可见AVP阳性神经元的胞体或突起;在不同核团内AVP阳性神经元的形态存在差异。结论:AVP及其mRNA阳性神经元在下丘脑不同核团内具有特异性分布;AVP阳性触液神经元可能是调节脑脊液和脑组织之间AVP含量的桥梁。     

植物雌激素对去卵巢大鼠海马NOS阳性神经元及学习记忆的影响

目的 :观察植物雌激素对去卵巢大鼠海马NOS阳性神经元及学习、记忆的影响 ,对中枢神经系统的保护作用。方法 :采用NADPH d酶组化观测各组大鼠海马各功能亚区NOS阳性神经元数目和Morris水迷宫行为学方法。结果 :定位航行实验显示各组大鼠的平均逃避潜伏期无明显差异 ,而空间探索实验显示植物雌激素组平台象限的游泳距离百分比和穿台次数均高于去卵巢对照组。在海马CA1和齿状回 (DG) ,植物雌激素组NOS阳性神经元数目较去卵巢对照组明显增多 (P <0 .0 5 )。结论 :植物雌激素能增加海马神经元NOS的表达 ,改善去卵巢大鼠的学习记忆能力 ,提示对中枢神经系统退行性病变具有保护作用。     

大鼠下丘脑内的一氧化氮合酶与雌激素受体双标神经元

目的:探讨一氧化氮合酶(NOS)和雌激素受体(ER)在下丘脑诸核团的分布及共存,为揭示雌激素与一氧化氮之间的内在联系提供形态学依据。方法:采用NADPH-d组织化学法并结合免疫组织化学技术,观察雌性大鼠下丘脑内NOS阳性神经元、ER阳性神经元以及NOS/ER双染神经元的形态及分布。结果:NOS阳性神经元主要分布在下丘脑室旁核、视上核、下丘脑外侧区和室周核;ER阳性神经元在下丘脑诸核团的表达不及NOS阳性神经元广泛;NOS与ER双染神经元主要分布在下丘脑的室旁核、视上核、下丘脑外侧区及室周核;其他区域可见散在分布的双染神经元。结论:NOS与ER双染神经元主要集中分布在视上核的背内侧和背外侧部及室旁核小细胞部腹内侧区,在下丘脑外侧区分布较广但比较分散,室周核呈散在分布。     

Effect of low estrogen on neurons in the preoptic area of hypothalamus of ovariectomized rats

The purpose of this study was to investigate the difference in neuronal activity in the preoptic area of the hypothalamus (POAH) under low estrogen condition induced by ovariectomy. One hundred and twenty sham-operated (SHAM) and ovariectomized (OVX) rats were placed in different temperatures for 2 h. Twelve rats from each group were stimulated by 4 °C, 10 °C, 25 °C, 33 °C and 38 °C, respectively. c-Fos expression in the POAH was detected by immunohistochemistry. Following exposure to warm and cold stimuli, there were markedly lower c-Fos-positive cell densities in the OVX group compared with the SHAM group in the median preoptic nucleus (MnPO) at 4 °C, 10 °C, 33 °C and 38 °C, in the medial preoptic area (MPA) at 25 °C and 38 °C, in the ventromedial preoptic nucleus (VMPO) at 4 °C, 10 °C and 38 °C and in the ventrolateral preoptic nucleus (VLPO) at 4 °C and 38 °C. Both temperature and surgery had an impact on c-Fos expression by two-way ANOVA method except in the lateral preoptic area (LPO). c-Fos expression differed within different nuclei of the two groups in the same and different temperature stimuli. This indicated that the temperature-sensitive nuclei in the POAH exhibited lower and different activities during temperature stimuli following ovariectomy, which possibly resulted in abnormal thermoregulation and menopausal symptoms.     

卵巢移植对去势大鼠海马神经元数量和ER-β、NG表达的影响

目的:观察去势大鼠卵巢移植后海马神经元数量变化及雌激素受体β(ER-β)和神经颗粒素(NG)表达的变化,评价卵巢移植对中枢神经的保护作用。方法:成年雌性SD大鼠行双侧卵巢切除术(OVX)后,在肾被膜下移植出生3日内乳鼠的卵巢,于干预后的4、7、14、21 d和28 d,通过Nissl染色计数海马神经元的数量,采用免疫组化法观察海马神经元ER-β和NG蛋白的表达情况,并与OVX组和正常对照组比较。结果:与OVX组相比,卵巢移植组随移植时间的延长,海马神经元的数量逐步恢复;ER-β和NG蛋白的表达在海马各区均有所升高(P<0.05)。结论:卵巢移植可以防止海马神经元数量的减少,并促进ER-β和NG表达,发挥雌激素对中枢神经系统的保护作用。     

Nuclear localization of estrogen receptor-immunoreactivity in the preoptic area of female rats and its reduction by intraventricular colchicine treatment.

The subcellular localization of estrogen receptor (ER) was investigated in the preoptic area of ovariectomized female rats by electron microscopic immunohistochemistry, using a monoclonal antibody to ER. ER-immunoreactivity was localized in the nuclei of neurons of the periventricular preoptic nucleus (Pe) and the medial preoptic area (MPA). ER-immunoreactivity had a speckled pattern in the nucleus, but was not observed in the nucleolus or cytoplasm. After intraventricular colchicine treatment, ER-immunoreactivity within the nucleus was reduced drastically in neurons of the Pe and the MPA. The possible mechanism by which colchicine alters ER-immunoreactivity is mentioned.     

Intrahypothalamic actinomycin-D: Sexual behavior and nucleolar ultrastructure in the steroid-primed ovariectomized rat and the intact cyclic rat

Nucleolar segregation, a condition incompatible with RNA synthesis, caused by actinomycin-D in preoptic area neurons results in an inhibition of steroid-induced sexual receptivity. When the nucleoli in the cells of the preoptic area returned to normal the animals displayed high levels of sexual receptivity. The data indicated a statistically significant positive correlation between sexual receptivity and normal appearing nucleoli in preoptic area neurons. Unilateral injections of Act-D (0.08 μg/1μl saline vehicle) into the medial preoptic area (MPOA) of intact, cyclic rats caused nucleolar segregation in the area of the injection with some diffusion of the drug to the contralateral MPOA and ipsilateral basomedial hypothalamus. When the volume of vehicle was reduced to 0.5 μl, the percentage of rats with nucleolar segregation in the latter two areas decreased to 13%.     

Ginkgo biloba extract EGb 761 attenuates hippocampal neuronal loss and cognitive dysfunction resulting from chronic restraint stress in ovariectomized rats

We have recently found that a combination of ovariectomy (OVX) and chronic restraint stress causes cognitive dysfunction and reduces hippocampal CA3 neurons in female rats and that estrogen replacement suppresses the OVX/stress-induced behavioral and morphological changes. In this study, we examined the effect of Ginkgo biloba extract (EGb 761), a popular herbal supplement, on the cognitive dysfunction and neuromorphological change in OVX/stress-subjected rats. Female Fisher 344 rats were randomly divided into three groups: vehicle-treated OVX, EGb 761 (50 mg/kg) -treated OVX and vehicle-treated sham-operated control groups. Two months after ovariectomy, all animals received restraint stress for 21 days (6 h/day), and were then subjected to a novel object recognition test followed by morphological examination by Nissl staining. EGb 761 was orally administered once daily until the behavioral analysis was done. Treatment with EGb 761 improved memory impairment and neuronal loss of hippocampus in the OVX/stress-subjected group in the same ways as 17beta-estradiol. On the other hand, EGb 761 did not affect the loss of bone mineral density and increase in body weight after OVX, although 17beta-estradiol attenuated them. These results have important implications for neuroprotective and cognition enhancing effects of EGb 761 in postmenopausal women and suggest that the effects are mediated by a different mechanism from estrogen.     

卵巢切除对椎体骨力学强度的影响研究

三个月龄SD雌性大鼠64只,平均体重180～240g,作双侧卵巢切除(OVX组)和假手术(Sham-O组):术后第1,3,5,7月取L2椎体。另职新生24～72小时雌性SD鼠48只,丝线结扎切除双前肢及尾根部,建立双后肢大鼠模型。3月时再同法分OVX及Sham-O组,术后第2,5,7月时分别处死动物切取L2椎体,在测量椎体几何形态后进行垂直压缩试验,结果显示:OVX组椎体平均高度减低(P<0.05),椎体上端前后缘变大(P<0.05),OVX组1月时椎体载荷及能承受的应力等均已明显下降(P<0.01),7月时降至低值。双后肢大鼠组:力学测试显示各阶段OVX组力学强度明显下降,各力学参数呈现较正常应力组为高的趋势,可能与双后肢站立后椎体承受的应力增加有关。椎体力学强度的减低,以致即便是较小的创伤亦具有极高的骨折危险性。     

The distributions of apoptotic cells in the medial preoptic areas of male and female neonatal rats

The medial preoptic area (MPA) of the hypothalamus of the rat contains two sexually dimorphic nuclei, the periventricular preoptic nucleus (PVpo) and the medial preoptic nucleus (MPN). To examine the relationship between sexual dimorphism and neuronal death, we examined the number of apoptotic cells in the subdivisions of the MPA in neonatal rats of postnatal days 1 (P1), 4 (P4), 7 (P7) and 14 (P14). Apoptotic cells in these areas were classified according to their progression into three stages. P1 and P4 rats contained many apoptotic cells in the subfield along the third ventricle, including the PVpo, and their number was significantly larger in P1 males: in particular, the number of early-stage cells was larger in males than females. The number of apoptotic cells in the MPN was increased in P4 and P7 rats, although no significant sexual differences were seen in the total number or in the number of each progressive stage of apoptotic cells. In P14 rats, very few apoptotic cells were seen in the MPA. Our data revealed that the distribution of apoptotic cells in the MPA of developing rats depends on the sexuality, subdivision of the area and postnatal period.