生理水平的雄激素对亚急性衰老小鼠学习记忆能力的影响

目的探讨生理剂量的外源性丙酸睾酮对亚急性衰老小鼠学习记忆能力的影响。方法将C57BL/6J雄性小鼠38只随机分为对照组(10只)、去势组(10只)、D半乳糖组(9只)、丙酸睾酮组(9只),3个月后对各组小鼠进行水迷宫和避暗穿梭实验,检测脑、肝脏组织的丙二醛、超氧化物歧化酶(SOD)水平,并由Nissl染色观测海马神经元的变化情况。结果去势组小鼠各项行为学指标均劣于对照组,大脑和肝脏的丙二醛水平明显升高,SOD水平明显下降(P0.05),大脑海马CA1区结构松散,神经元数量明显减少(P0.01);与去势组比较,D半乳糖组的行为学指标进一步恶化,大脑丙二醛水平明显升高,SOD水平明显下降,大脑海马CA1区结构紊乱,神经元丢失严重(P0.05);而丙酸睾酮组的上述各项指标与对照组比较,差异无统计学意义。结论雄激素可以逆转亚急性衰老小鼠学习记忆能力的衰退。降低体内氧自由基水平,改善大脑海马CA1区形态,增加CA1区神经元数量,可能是其机制之一。     

雄激素缺乏小鼠体内活性氧和Rb蛋白表达的变化及对心脏衰老的影响

目的 探讨小鼠体内雄激素水平缺乏对心脏衰老的影响.方法 实验分为正常C57BL/ 6J雄鼠组(n=8)、去势组(n=8)、睾丸女性化鼠(tfm)组(n=10)、衰老组(n=8).测定各组血清睾酮浓度,分离心肌组织测定组织超氧化物歧化酶(SOD)和丙二醛(MDA)水平以及Western印迹测定去磷酸化Rb蛋白表达量.结果 与正常组相比,衰老组、去势组和tfm组血清睾酮浓度明显下降(P<0.01);心肌组织中SOD活性下降(P<0.05,P<0.01)、MDA含量增加(P<0.01);去磷酸化Rb蛋白表达量增加(P<0.01).与衰老组相比,去势组和tfm组SOD活性、MDA含量及去磷酸化Rb蛋白表达量差异无统计学意义.结论 体内雄激素水平缺乏可能通过增加活性氧水平(ROS)及Rb蛋白表达导致小鼠心肌组织衰老.     

慢性应激对快速老化小鼠学习能力的影响

目的观察慢性应激对4月龄快速老化小鼠(SAMP8)空间学习能力的影响并探讨可能的机制。方法 4月龄SAMP8和同龄正常老化小鼠(SAMR1)分别分成对照组和应激组。应激组小鼠给予连续4 w,每天2 h的束缚性应激。4 w后各组小鼠分别进行Y迷宫实验和海马DG区神经干细胞增殖的检测。结果应激组SAMP8 5 d Y迷宫测试总的正确反应数明显少于应激组SAMR1(P<0.01);应激组SAMP8海马BrdU阳性细胞数明显少于应激组SAMR1小鼠(P<0.01)。结论与同龄SAMR1小鼠相比,4月龄SAMP8小鼠存在对慢性应激损伤的易感性,这种应激易感性可能是SAMP8成年后快速老化的原因之一。     

雄激素缺乏及外源性睾酮对雄性小鼠心脏衰老的影响

目的探讨雄激素缺乏是否与心脏衰老有关,以及不同剂量丙酸睾酮对心脏衰老的影响。方法雄性C57BL,/6J小鼠32只随机分为正常组(8只)、去势+安慰剂组(去势组,8只)、去势+生理剂量睾酮组(生理剂量组,8只)、去势+大剂量睾酮组(大剂量组,8只)。治疗3个月后测定各组血清睾酮浓度,分离心肌组织荧光实时定量PCR测定端粒长度以及Western b10t测定去磷酸化Rb蛋白表达量。结果与正常组比较,去势组小鼠睾酮明显降低(P0.01),端粒长度明显缩短(P=0.029),去磷酸化Rb蛋白表达明显增加(P0.01)。治疗3个月后,与去势组比较,生理剂量组小鼠端粒长度明显延长(P0.01);去磷酸化Rb蛋白表达明显减少(P0.05);大剂量组小鼠端粒长度进一步缩短(P0.05);去磷酸化Rb蛋白表达进一步增加(P0.01)。结论雄激素缺乏小鼠心肌组织发生衰老,给予生理剂量睾酮可延缓心脏衰老,大剂量睾酮对心脏衰老有促进作用。     

亚甲蓝对APP/PS1小鼠海马CA1区树突棘密度的保护作用

目的探讨亚甲蓝(MB)对APP/PS1转基因小鼠海马CA1区树突棘密度改变及学习记忆能力改善的影响。方法 APP/PS1小鼠及相同品系的3月龄野生小鼠,随机分为3组,每组10只:正常对照组,为野生小鼠。模型组,为APP/PS1小鼠;治疗组,3月龄的APP/PS1小鼠口服亚甲蓝25 mg·kg-1·d-1;连续用药4个月。待3组小鼠均为7月龄时,跳台实验测试3组小鼠的学习记忆能力;高尔基染色观察各组海马CA1区树突棘密度的变化。结果亚甲蓝治疗组小鼠跳台试验错误次数减少,小鼠跳台试验的潜伏期明显延长(P<0.01);治疗组与模型组相比海马CA1区树突棘密度明显增加(P<0.01),治疗组与对照组无统计学差异(P>0.05)。结论亚甲蓝可能是通过增加海马CA1区树突棘密度来改善APP/PS1小鼠的学习记忆能力。     

柴胡疏肝散对抑郁症模型大鼠海马单胺氧化酶与乙酰胆碱酯酶活性的影响

目的 观察柴胡疏肝散对大鼠大脑海马乙酰胆碱酯酶(AChE)与单胺氧化酶(MAO)活性的影响.方法 选取60只4～5月龄的SD大鼠随机分为正常组、模型组、氟西汀组和中药组,共4组,每组15只.利用孤养结合慢性轻度不可预见性应激刺激制造抑郁症模型.21 d后,采用敞箱实验、糖水消耗量检测和体重检测等指标评定大鼠行为学改变,并用免疫组织化学染色法观察大鼠大脑海马区AChE的蛋白表达变化,利用比色法检测大鼠大脑海马区MAO活性.结果 与正常组相比,模型组水平运动得分、垂直运动得分、体重和糖水偏爱度均明显降低(P<0.01),与模型组比较,氟西汀组和中药组水平运动得分、垂直运动得分、糖水偏爱度与体重均明显升高(P<0.05～0.001);免疫组化结果显示,与正常组相比,模型组海马区AChE的蛋白表达均明显升高(P<0.05),与模型组相比,氟西汀组和中药组大鼠海马区AChE的蛋白表达均明显降低(P<0.05);比色法结果显示,与正常组相比,模型组海马区MAO活性明显升高(P<0.05),与模型组相比,氟西汀组、中药组海马区MAO活性明显下降(P<0.05).结论 柴胡疏肝散抗抑郁症的作用可能与其降低大脑组织海马区AChE蛋白表达和MAO活性有关.     

补肝养髓法对老年性痴呆海马神经元RNA和Nissl体的定量研究

目的观察补肝养髓法对自发老年性痴呆模型海马神经元内RNA和Nissl体的影响.方法用跳台实验(step-downtest)从21月龄昆明种小鼠筛选出自发老年性痴呆(记忆障碍)鼠,随机分为空白对照组、西药对照组、补肝养髓小剂量组、补肝养髓大剂量组,另设老年学习记忆正常组(老年正常组).西药对照组给以喜得镇(Hydergine)0.6mg/kg,补肝养髓小、大剂量组分别予补肝养髓方6.80 g/kg及20.41g/kg,连续60 d,正常对照和痴呆对照组均灌以等量双蒸馏水(DW);脑组织冰冻切片,细胞化学方法显示大脑皮质和海马神经元内RNA和Nissl体,全自动显微图像分析系统定量检测相关脑区RNA和Nissl体含量.结果补肝养髓法能显著增高大脑皮质和海马锥体细胞的RNA和Nissl体含量,而且其作用呈现出一定的量效关系.结论补肝养髓方可明显改善自发老年性痴呆模型的学习记忆关键脑区海马的神经元结构,并显著改善其海马神经元的RNA代谢.     

脑心通胶囊对拟血管性痴呆大鼠行为学和海马细胞形态学的影响

目的研究脑心通胶囊对血管性痴呆（VD）大鼠学习记忆能力和海马细胞形态的影响。方法采用大脑中动脉梗死（MCAO）法制成VD大鼠模型后随机分为脑心通组（中药组）、西药组、模型组，另设假手术组和正常组，共治疗28d，治疗后以Morris水迷宫实验检测其学习记忆行为能力，以HE染色、Nissl染色检测其细胞形态的变化。结果脑心通胶囊可以改善VD大鼠学习记忆能力，明显减轻缺血对海马CA1区锥体细胞的损伤。结论脑心通胶囊为治疗VD大鼠的有效方，其治疗机制可能与减轻缺血对海马CA1区锥体细胞的损伤有关。     

霍乱毒素B亚单位增强抗原效应抑制痴呆鼠病变形成的研究

目的探讨黏膜佐剂霍乱毒素B亚单位(CB)对β淀粉样多肽(Aβ)抗原效应的增强作用及对脑中Aβ斑块形成的抑制作用。方法选取转基因阳性痴呆模型鼠24只,至7月龄时,随机分为Aβ+CB组、Aβ+铝佐剂(AL)组、单Aβ抗原组、阳性对照组,每组6只,另6只转基因阴性鼠作为阴性对照组。鼻腔滴入佐剂,1次/周,持续5个月,间接ELISA法测血清抗体效价,Morris水迷宫实验测小鼠的行为学能力,双抗夹心ELISA法测脑中Aβ含量,免疫组织化学染色观察脑中Aβ斑块形成。结果免疫5个月后,Aβ+CB组抗体效价最高,为14 000,Aβ+AL组为12 000。与阳性对照组比较,Aβ+CB组寻找隐性平台时间缩短约50%(P<0.05),Aβ+AL组变化不明显(P>0.05);Aβ+CB组脑中Aβ含量明显减少(P<0.05),Aβ+AL组略有降低(P>0.05);Aβ+CB组海马区、皮质区Aβ斑块分别减少56.4%、45.6%(P<0.05),Aβ+AL组斑块减少不明显(P>0.05)。结论黏膜佐剂CB增强Aβ抗原的效应、抑制痴呆鼠脑中Aβ斑块形成,改善小鼠学习记忆能力的作用较LA更明显。     

金针菇多糖对衰老小鼠大脑抗氧化能力的影响

目的研究金针菇多糖(FVP)对衰老小鼠大脑抗氧化能力的影响。方法 ICR小鼠60只,雌雄各半,按体重随机分为6组:空白对照组,模型组,脑复康组,FVP低、中、高剂量组,实验动物喂饲6 w,处死小鼠,计算小鼠脏器指数;测量大脑抗氧化指标丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px);HE染色观察海马组织形态学改变。结果与模型组比较,FVP组脑指数显著上升(P0.05),脾脏、肝脏指数显著下降(P0.05);MDA含量显著下降(P0.05),GSH-Px和SOD活性显著上升(P0.05);FVP组显著改善海马神经元的变性、脱落。结论FVP可使衰老小鼠大脑产生抗氧化作用,可能是其抗衰老的作用机制之一。     

Androgen and estrogen receptors in brain cytosol from male, female, and testicular feminized (tfm/y hermaphrodite) mice.

Specific binding of [3H] 5alpha-dihydrotestosterone (DHT) and [3H] estradiol by cytoplasmic extracts from whole brain of castrated male, female, and androgen-insensitive, testicular feminized (tfm/y male-female), mice has been investigated using glycerol gradient centrifugation and charcoal assay. Mouse brain cytosol contains macromolecules with the characteristics of steroid hormone receptors, binding preferentially with high-affinity androgens or estrogens. Both DHT- and estradiol-receptor complexes migrate at 8-9 S in gradients at low ionic strength and at 4-5 S in gradients containing 0.5M KCl. KD's (mean +/- SE) for DHT binding by brain cytosol from castrated males, females, and tfm/y male-female are 1.1 +/- 0.4, 0.9 +/- 0.4, and 0.8 +/- 0.1 X 10(-9)M, respectively. DHT binding activity in brain cytosol from tfm/y male-female mice is reduced to about 20-30% of that from their normal littermates, as is the case for tfm/y male-female kidney cytosol. The residual androgen receptor in tfm/y male-female brain cytosol has normal sedimentation properties. Unlike the situation for androgen binding, the number of estradiol binding sites is comparable in brain cytosol from male, female, and tfm/y male-female mice. KD's (mean +/- SE) for estradiol binding are 1.6 +/- 0.5 X 10(-10)M for castrated males, 2.4 +/- 0.4 X 10(-10)M for females, and 1.8 +/- 0.4 X 10(-10)M for tfm/y male-female. Cross-competition experiments with unlabeled estradiol, DHT, or testosterone, have shown a difference in the degree of specificity of the androgen and estrogen receptors, the estrogen receptor having considerably more specificity. For the interaction of estradiol with the androgen receptor, the Ki is 8-9 X 10(-9)M. The decrease in the number of DHT binding sites in the brain of tfm/y male-female mice without a concomitant decrease in estradiol binding sites, and the different specificities of the two sites, point to the existence of distinct androgen and estrogen receptor molecules in mouse brain cytosol.     

Blockade of testosterone-induced mounting behavior in the male rat with intracranial application of the aromatization inhibitor, androst-1,4,6,-triene-3,17-dione.

Propylene glycol (glycol) solutions containing either testosterone (T) or estradiol (E2) were infused directly into the preoptic area (POA) of longterm castrated rats in order to reinstate male copulatory behavior. In addition, castrated males were administered T or E2 in the POA in combination with a steroid that has been shown to block the aromatization of testosterone to estradiol, androst-1,4,6-triene-3,17-dione (ATD). The facilitatory action of testosterone on mounting behavior was blocked when it was given in combination with ATD. Animals treated in the POA with glycol +T, glycol +E2 or ATD + E2 all showed significant increases in mounting behavior over preimplant levels. There was no significant rise in the number of intromissions or ejaculations in any of the hypothesis that, at least for mounting behavior, aromatization is necessary for the stimulation of male sexual behavior by testosterone.     

Effects of the gonadotrophin-releasing hormone agonist 'Zoladex' upon pituitary and gonadal function in hypogonadal (hpg) male mice: a comparison with normal male and testicular feminized (tfm) mice.

Hypogonadal (hpg) mutant mice, with a congenital deficiency of hypothalamic gonadotrophin-releasing hormone (GnRH), and testicular feminized (tfm) mice, which lack a functional androgen receptor, were used to study the effects of the potent GnRH agonist 'Zoladex' (ICI 118630; D-Ser (Bu(t))6, Azgly10-GnRH) on pituitary and gonadal function. Zoladex (0.5 mg) in a sustained-release lactide-glycolide copolymer depot was administered subcutaneously under anaesthesia and was left in place for 7 days, after which time the effects of the drug upon pituitary and serum gonadotrophin concentrations, glycoprotein hormone subunit mRNAs and testicular morphology were investigated. At the pituitary level, Zoladex treatment resulted in a substantial reduction in LH content in normal males, and LH content was depressed in hpg mice even below the basal levels normally found in these mutants. Pituitary LH content in the Zoladex-treated animals was depressed in the tfm groups, but not to the same levels as those found in the normal and castrated normal mice. Zoladex treatment at the time of castration prevented the post-operative elevation in serum LH associated with castration alone. In the androgen-deficient tfm mouse, Zoladex did not depress the normally elevated serum LH levels. Serum LH in the hpg animals was, in all cases, below the limit of detection of the assay. Pituitary FSH content was depressed into the hpg range in both the normal and castrated animals, but there was no further depression in the hpg mice. The pituitary content was reduced in the tfm mice, again the effects not being as dramatic as in the normal and castrated animals. Serum FSH content, as measured by radioimmunoassay, was depressed by 50% in normal mice; there was no reduction in the hpg mice, however. With regard to pituitary gonadotrophic hormone gene expression, Zoladex administration to normal mice caused a dramatic reduction in LH beta mRNA content, to a level approximating that found in untreated hpg mice. The drug also depressed LH beta mRNA in the castrated group to the hpg range when given at the time of castration, whereas in untreated castrated mice there was a significant increase in LH beta mRNA. In the tfm mouse, which can be considered as a model for long-term failure of androgen feedback, Zoladex again induced a fall in LH beta mRNA, but not to the same extent as in the normal and normal castrated group. Zoladex had no effect on the already low levels of LH beta mRNA found in hpg mice.(ABSTRACT TRUNCATED AT 400 WORDS)     

Endocrine status of the testicular feminized male (TFM) rat

The plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), androstenedione (A), dihydrotestosterone (DHT), corticosterone and corticosterone binding globulin (CBG) were determined in 160- and 350-day testicular feminized male (tfm) and normal littermate (NL) rats. In the younger group the concentrations of T, A, DHT and 5α-androstan-3α,17β-diol (Adiol) were also determined in testis tissue.Tfm rats showed a greatly elevated plasma LH indicating lack of androgen feedback. Plasma FSH, however, was normal in both age groups, suggesting that inhibin production from tfm testes was relatively unaffected.Intratesticular concentrations of A were greatly elevated in the tfm animals at both ages whilst the testicular levels of T were highly reduced when compared to NL rats. This indicates a gonadal deficiency of the 17β-hydroxy steroid dehydrogenase (17β-HSD). Furthermore, the relatively low T: DHT ratio and high concentrations of Adiol in the tfm testes confirmed previous reports that the high 5α-reductase typical for the immature rat testis is maintained into adulthood in rats with the tfm condition. A considerable degree of peripheral conversion (A → T) probably helps to maintain normal or supranormal plasma levels of T. Gonadectomy rendered all plasma androgens undetectable, indicating that the adrenal contribution was negligible.Increasing age (350 days) was associated with a marked increase in circulating androgens in tfm rats. This is probably the reason for the observed significant reduction in circulating LH in this age group when compared to the 160-day animals. The aging tfm rat is predisposed to testicular tumors which, on the basis of histology, specific [¹²⁵I]hLH binding and in vitro responsiveness to hCG, appear to be of Leydig cell origin.Microflow fluorometry (MFF) of tfm testis cell suspensions revealed the presence of haploid cells, suggesting that meiosis proceeds to a limited extent.Plasma corticosterone levels in the tfm rat were normal although plasma CBG levels were highly significantly elevated at both ages when compared to the levels in NL rats. We suggest that the adrenal hyperplasia observed in tfm rats is secondary to reduced corticosterone production and diminished free corticosterone in the circulation.     

雄激素缺乏对雄性大鼠血管内皮细胞的影响

目的:观察雄性大鼠去势后,雄激素缺乏对血管内皮细胞功能和结构的影响。方法:雄性Wistar大鼠20只随机化分为单纯去势组(10只)和假手术组(10只)。8周后,用放射免疫法测定两组大鼠血浆睾酮的浓度,取胸主动脉HE染色后,观察血管内皮细胞的形态变化;采用化学比色法测定血浆一氧化氮(NO)的水平,用ELISA法检测血清内皮素-1(ET-1)的含量。结果:与假手术组相比较,单纯去势组血浆睾酮的浓度及血浆NO的水平均显著降低,分别为[(2.47±0.53)μg/L vs.(0.28±0.07)μg/L和(33.44±8.50)μg/L vs.(21.61±10.51)μg/L,P<0.05];而血浆ET-1的含量则明显升高[(3.84±0.16)μg/L vs.(4.41±0.34)μg/L,P<0.05]。单纯去势组血管平滑肌细胞的排列不整齐,管壁厚薄欠均匀,血管内皮细胞增生。结论:雄性大鼠去势后雄激素缺乏可使大鼠血管内皮受损,释放NO减少以及ET-1增加。     

外源性睾酮对高脂饮食去势雄兔冠状小动脉的影响

目的 了解外源性睾酮对高脂饮食去势雄免冠状小动脉的影响。方法 雄性新西兰白兔35只随机分成对照组、单纯去势组、低睾酮血症补充组、生理睾酮血症补充组和高睾酮血症补充组共5组，除对照组外其余各组行去势手术，术后对后3组肌注十一酸睾酮（TU），剂量分别是3，6，12mg／kg，形成低睾酮血症、生理水平睾酮血症、高睾酮血症，测定血清雌二醇（E2）、睾酮（T）水平和E2／T比值的变化，动物于第12周末处死．心肌切片染色，测定肌间小动脉硬化发生率、内膜增厚发生率、计算内膜面积占有率（RIA）、内膜／中膜比值。结果 肌间小动脉粥样硬化发生率、肌间小动脉内膜增厚率、RIA、内膜／中膜：对照组与生理睾酮血症补充组相当且均明显低于单纯去势组、低睾酮血症补充组和高睾酮血症补充组（P〈0．05）。结论 补充生理水平的外源性睾酮能降低高脂饮食去势雄兔的冠状小动脉粥样硬化发生率、肌间小动脉内膜增厚率、RIA，改善内膜／中膜比值，从而改善动脉粥样硬化。     

外源性睾酮对去势雄兔早期动脉硬化的作用

目的旨在研究外源性睾酮对去势高脂饮食雄性家兔早期动脉硬化的影响,希望能为雄激素在临床合理应用提供一定的理论依据。方法将30只雄性新西兰白兔随机分为3组:外源性睾酮组、生理水平组与对照组。制备高脂并不同睾酮水平的雄兔模型,12周处死后测定雄兔血脂、载脂蛋白水平;观察并测量冠状动脉及肾动脉的内膜厚度。结果外源性睾酮组血清总胆固醇、甘油三酯、低密度脂蛋白胆固醇、载脂蛋白B明显高于对照组和生理水平组(P<0.01);外源性睾酮组冠状动脉早期动脉硬化的程度重于对照组和生理水平组(P<0.05)。结论补充高于生理剂量的外源性睾酮对于去势高脂饮食雄兔冠状动脉早期动脉硬化有促进作用。     

Testosterone down-regulates ornithine aminotransferase gene and up-regulates arginase II and ornithine decarboxylase genes for polyamines synthesis in the murine kidney

The enzymes ornithine aminotransferase (OAT) and ornithine decarboxylase (ODC) share L-ornithine as a common substrate and arginase II produces this amino acid. In the murine kidney, testosterone induced ODC gene expression and polyamine production, but it is unknown how OAT gene is expressed under androgen treatment. These experiments were designed to study the influence of testosterone on the renal expression of OAT gene. Pharmacological and physiological doses of testosterone were injected into female and castrated male mice. Total RNA and soluble proteins extracted from whole kidneys were analyzed by Northern and Western blots, respectively. The results clearly indicate that pharmacological doses of testosterone simultaneously down-regulated the level of OAT protein and up-regulated the expression of arginase II and ODC genes. Variations of the levels of OAT protein and arginase II mRNA and protein were strongly correlated with testosteronemia. Orchidectomy increased the renal level of OAT protein and decreased that of ODC and arginase II. These effects were reversed by injecting a physiological dose of testosterone into castrated male mice. In conclusion, OAT and ODC genes are inversely regulated by testosterone in the mouse kidney. Consequently, in kidneys of testosterone-treated mice, L-arginine-derived ornithine produced by arginase II might be preferentially used by ODC for putrescine production rather than by OAT. This metabolic fate of L-ornithine was facilitated by decreasing OAT gene expression. In contrast, in female and castrated male mice devoided of testosterone, OAT gene is highly expressed and L-ornithine is converted into L-glutamate.