雌二醇对离体大鼠缺氧—复氧心脏的保护作用

本实验采用离体大鼠心脏灌注模型，观察雌二醇对缺氧－复氧心脏收缩功能及超微结构的影响。结果表明，雌二醇对缺氧－复氧心肌具有一定的保护作用，这一作用此雌激能相对提高缺氧－复氧心肌组织中谷胱甘肽过氧化物酶活性和相对降低其Ｃａ＾２＋含量有关。     

HO-1在保护缺氧-复氧心脏中的作用及其机制研究

目的：研究血红素氧化酶1（HO-1）在对抗 心肌缺氧-复氧损伤中的作用，并探讨环氧化酶2（COX-2）是否参与其作用机制。 方法：采用离体大鼠心脏Langendorff灌流模型，观察心功能和酶学等指标。 结果：（1）HO-1的诱导剂高铁血红素可明显抑制缺氧-复氧心脏LVEDP增高 ，LVDP和±dp/dtmax的下降；减少复氧期LDH释放，缩小心肌梗死面积（P <0.01）。（2）HO-1的抑制剂可加重缺氧-复氧心脏LVDP和±dp/dtmax下 降，LDH释放和梗死面积明显高于单纯缺氧-复氧组（P<0.05）。（3）GC的抑制剂亚甲 蓝和COX-2的抑制剂塞来昔布均可部分取消高铁血红素降低缺氧-复氧心脏LVEDP，增加LVDP 和±dp/dtmax的作用，使LDH的释放和梗死面积明显增加（P<0.05） 。 结论：诱导HO-1增加可保护缺氧-复氧心肌，其作用可能通过激动鸟苷酸 环化酶途径，继而调节COX-2的活性来完成。     

钙激活钾通道在缺氧后处理对心肌保护的作用

目的： 探讨缺氧后处理在全心停灌缺氧模型中是否具有对抗心肌缺氧/复氧（A/R）损伤的作用，以及钙激活钾通道（KCa）和线粒体透性转换孔道（mPTP）是否参与缺氧后处理的抗心肌缺氧/复氧损伤。方法： 采用离体大鼠心脏Langendorff灌流模型，全心缺氧30 min、复氧120 min复制A/R模型。测定心室力学指标和复灌各时点冠脉流出液中乳酸脱氢酶（LDH）含量。实验结束测定心肌组织甲臜（formazan）含量。分离心肌线粒体，测定高钙诱导下mPTP的开放情况。结果： 缺氧后处理心肌细胞的formazan含量明显高于、而复灌期间冠脉流出液中LDH含量低于单纯A/R组，明显改善心室力学指标，缓解冠脉流量的减少。KCa通道阻断剂paxilline能明显阻断缺氧后处理的心肌保护作用。缺氧后处理心肌细胞的mPTP开放程度显著低于A/R组。结论： 缺氧后处理具有抗心脏缺氧/复氧损伤的作用，这种保护作用可能与其抑制KCa通道的开放和降低mPTP的开放有关。     

线粒体渗透转换孔在肿瘤坏死因子α诱导的抗心肌缺氧/复氧损伤中的作用

目的：研究肿瘤坏死因子α（TNFα）诱导的抗心肌缺氧/复氧损伤的保护作用是否与抑制线粒体渗透转换孔的开放有关。 方法： 采用离体大鼠心脏灌流方法，结扎冠状动脉左前降支30 min和复氧120 min复制局部缺氧/复氧损伤模型，测定心肌梗死面积、冠脉流出液中乳酸脱氢酶（LDH）含量及各项心室力学指标。 结果： 与单纯缺氧/复氧组相比，1×104 U/L TNFα预处理明显降低心脏缺氧/复氧后的梗死面积和复氧期冠脉流出液中LDH含量，促进左室发展压、左室做功和左室舒张末压力的恢复。线粒体渗透转换孔开放剂atractyloside和钙激活钾通道阻断剂paxilline减弱了TNFα的作用。 结论： TNFα诱导的抗心肌缺氧/复氧损伤的保护作用可能与其抑制线粒体渗透转换孔的开放及促进钙激活钾通道的开放有关。     

多胺对大鼠缺氧-复氧心肌细胞内钙的影响

目的：观察外源性低浓度多胺对大鼠缺氧-复氧心肌细胞钙超载的影响。 方法: 酶解分离大鼠心室肌细胞，用正常氧合Tyrode液灌流8 min, 换为缺氧液灌流32 min, 再转换为正常氧合Tyrode液灌流8 min,复制心肌缺氧-复氧模型。分别在缺氧前给予精胺，缺氧-复氧后给予精胺、精脒、腐胺。应用激光扫描共聚焦显微镜（LSCM）连续观察细胞内钙荧光强度的动态变化。 结果: 精胺（1 mol/L）对正常静息状态下大鼠心室肌［Ca2+］i无影响。缺氧前给予精胺，可取消复氧引起的心肌［Ca2+］i增高；缺氧-复氧后给予精胺、精脒、腐胺对缺氧-复氧引起［Ca2+］i升高也有不同程度的降低作用，其中以精胺的作用最强。复氧后给予精胺降低缺氧-复氧［Ca2+］i 升高的作用小于缺氧前给予。 结论: 缺氧前给予精胺可拮抗缺氧-复氧心肌细胞钙超载发生；复氧后给予精胺可使缺氧-复氧心肌细胞钙超载减轻，但其作用力度不如缺氧前给药。多胺拮抗缺氧-复氧心肌细胞钙超载的作用以精胺＞精脒＞腐胺的顺序递减。     

各部位心肌细胞对硝酸酯类药物预适应能力的实验研究

目的： 研究各部位的心肌细胞对缺氧再复氧损伤的耐受能力、产生缺氧预适应的能力以及一氧化氮产生预适应保护心肌细胞的途径。 方法： 培养不同部位的心肌细胞（心房、左心室、右心室、心尖和全心脏），分别给予下列的刺激：缺氧复氧，缺氧预适应，低浓度精氨酸预适应，高浓度精氨酸预适应，观察细胞坏死率、细胞凋亡率、培养液中乳酸脱氢酶浓度、细胞内游离钙离子浓度以及细胞内蛋白激酶C的活性强度变化等。 结果： 实验表明，缺氧复氧损伤可以造成不同部位间心肌细胞坏死率和凋亡率明显升高，培养液中LDH的含量增加，细胞内钙离子超载，但各组细胞间并没有明显区别（P>0.05）。给予缺氧预适应后，细胞损伤的各种指标均显著低于缺氧复氧组（P<0.05）。给予细胞不同浓度的精氨酸处理，这些指标同样程度的低于缺氧复氧组（P<0.05），同时细胞内蛋白激酶C的活性高于缺氧复氧组（P<0.05）。 结论： 药物预适应可以对缺氧复氧损伤产生明显的拮抗作用，它可能是通过激活细胞内蛋白激酶C来发挥作用的，而各部位的心肌细胞产生药物预适应的能力没有显著性差别。     

维拉帕米和Mn~（2＋）对缺氧及复氧单心肌细胞游离Ca~（2＋）的影响

本文采用荧光探针Ｆｕｒａ－２结合计算机图像处理技术观察不同时间的缺氧及复氧单心肌细胞内游离Ｃａ￣（２＋）含量的变化以及Ｃａ￣（２＋）通道阻滞剂及Ｎａ￣＋－Ｃａ￣（２＋）交换抑制剂对其的响。结果显示随着缺氧和缺氧复氧时间的延长，细胞内Ｃａ￣（２＋）浓度逐渐增加。缺氧复氧时细胞内Ｃａ￣（２＋）增加幅度较单纯缺氧大。Ｍｎ￣（２＋）及维拉帕米均能降低缺氧时心肌细胞内Ｃａ￣（２＋）超负荷（Ｐ＜０．０５）。Ｍｎ￣（２＋）同时也能降低缺氧复氧时细胞内Ｃａ￣（２＋）含量（Ｐ＜０．０５），而维拉帕米降钙作用不明显（Ｐ＞０．０５）。本文提示缺氧和缺氧复氧时细胞内Ｃａ￣（２＋）超负荷的机制并非完全一致。     

山莨菪碱和异搏定对离体大鼠心脏“缺氧—复氧”损伤的防治作用比较

本文在离体大鼠心脏灌流模型上,比较山莨菪碱与异搏定对心脏缺氧—复氧损伤(氧反常)的防治作用,结果发现在缺氧期向灌流液中加入山莨菪碱(1.64×10~(-4)M),与异搏定(5×10~(-8)M)都能有效地减轻心脏缺氧—复氧损伤,表现为心功能的恢复,心肌酸中毒和细胞内乳酸脱氢酶的漏出,心肌组织脂质过氧化产物与钙含量增加的程度都有明显改善。然而在复氧灌流期应用异搏定并不能阻止氧反常的发生;但山莨菪碱在复氧期应用时,也能显著减轻氧反常损伤。结果提示山莨菪碱可能具有除钙拮抗作用以外的更广泛的抗缺氧—复氧损伤机制,值得进一步探讨。     

β-肾上腺素能刺激促进离体小鼠心脏缺氧/复氧诱导的细胞凋亡

目的：观察β-肾上腺素能刺激与缺氧/复氧损伤对离体小鼠心脏细胞凋亡的影响。 方法： 逆行灌注离体小鼠心脏，观察不同剂量异丙基肾上腺素（Iso）和不同时间缺氧/复氧心肌细胞凋亡率的变化，并观察β1-肾上腺素能受体阻滞剂、caspase-拮抗剂、Bcl-2对其凋亡率的影响，以TUNEL法检测心肌细胞凋亡率。 结果： 单独Iso未引起心肌细胞凋亡率的变化，但可增加缺氧/复氧所诱导的细胞凋亡率；Bcl-2转基因鼠细胞凋亡率明显低于正常小鼠；β1-受体拮抗剂（美托洛尔）及caspase -拮抗剂（zVAD.fmk）可明显抑制Iso和缺氧/复氧所致细胞凋亡。 结论： β-肾上腺素能受体激动剂可促使缺氧/复氧所诱导心肌细胞凋亡，其诱导凋亡的作用主要通过β1-受体介导，β1-受体拮抗剂可抑制二者共同作用所诱导心肌细胞凋亡。     

缺氧－复氧幼狗心肌细胞冷冻蚀刻电镜观察

本实验以幼狗心脏为实验对象，应用冷冻蚀刻技术观察ＡＴＰ－ＭｇＣｌ２对缺氧－复氧幼狗心肌细胞，尤其是膜结构的影响。结果表明，缺氧－复氧对照组心肌细胞损伤较重，而ＡＴＰ－ＭｇＣｌ２组心肌细胞损伤轻ｑ提示，ＡＴＰ－ＭｇＣｌ２对缺氧－复氧幼狗心肌细胞质膜、线粒体等超微结构有保护作用。     

The effect of estradiol and progesterone on the sexual behavior of ovariectomized mares

Daily treatment (5 days) with estradiol resulted in increased levels (p less than 0.05) of proceptive behavior in ovariectomized as compared to control mares (N = 8 per treatment) within 4 hr of injection and for the 4 subsequent days. Ejaculations occurred more often (p less than 0.05) in estrogen-treated mares on days 2-5, but the number of precopulatory investigations by the stallions was not altered. Progesterone treatment resulted in an absence of sexual behavior except in one mare on Day 1. Control mares exhibited varying levels of sexual interest. The concurrent administration of estradiol and progesterone produced a biphasic effect on proximity-related behaviors. Proximity behaviors were initially (Day 1) greater and subsequently less in the group treated with both hormones than in the group treated with estradiol alone. Injections of free estradiol resulted in a shorter latency to effect for two measures of proceptivity than did injections of estradiol benzoate. A dose response test for progesterone showed no effect with 0, 1, or 10 mg, but 100 mg was inhibitory (p less than 0.05). These results demonstrated that within 4 hr estradiol stimulated, while progesterone inhibited estrous behavior in ovariectomized mares and that concurrent administration of estradiol and progesterone produced a biphasic effect, first enhancing, then suppressing some aspects of the estrous response. The relatively short latency to action of all treatments and the biphasic effect of concurrent estradiol and progesterone may be attributable to low level, endogenous hormones.     

Long-term transdermal dihydrotestosterone therapy: effects on pituitary gonadal axis and plasma lipoproteins

In order to investigate whether dihydrotestosterone (DHT) alone has an inhibiting effect on pituitary luteinizing hormone (LH) secretion, and whether this natural androgen has any effect on plasma lipids when administered transdermally, dihydrotestosterone was applied for 3 mth in a daily dose of 125 or 250 mg in gel form for transdermal absorption (Andractim) to elderly males with relatively low plasma testosterone levels. The results clearly show that DHT inhibits LH secretion, as plasma LH levels were decreased, although testosterone, free testosterone, estradiol and free estradiol levels were decreased. Regarding plasma lipid levels, DHT administration for 3 mth resulted in a moderate decrease in plasma cholesterol and low-density lipoprotein (LDL) levels, and a slight decrease in high-density lipoprotein (HDL)-cholesterol levels, the HDL/TLC ratio remaining constant. This suggests that percutaneous DHT administration is a relatively safe modality of androgen replacement therapy as far as atherogenicity is concerned.     

Epidermal growth factor induces the progesterone receptor in fetal uterine cells in culture: antagonistic effect of antiestrogens

Cells isolated from the uterus of the guinea pig foetus can be maintained in culture even through several sub-cultures. In these cells, estradiol increases progesterone receptor concentrations 2 o 3 times, although estradiol has no effect on cell proliferation. Epidermal growth factor (EGF) stimulates both cell proliferation and the progesterone receptor 4-Hydroxytamoxifen, a tamoxifen metabolite and potent anti-oestrogen, completely inhibits the stimulatory effect of EGF on the progesterone receptor but has no effect on the EGF-induced cell growth. These cells have specific binding sites with high affinity for 125I-EGF. Estradiol increases the number of binding sites but does not affect the affinity for EGF. 4-Hydroxytamoxifen has no significant effect on either the number of binding sites or the binding affinity. In conclusion, EGF could be an autocrine or paracrine factor in estrogen-sensitive cells not only as a potent mitogen but also as a factor capable of increasing an estrogen-induced protein like the progesterone receptor. The observation that an anti-estrogen can also act as an "anti-growth factor" suggests a close relationship between estrogens and growth factors.     

Effect of estradiol on mouse uterine epithelial cell transepithelial resistance (TER)

PROBLEM: The effects of estradiol on epithelial cell function in the uterus may either be direct or indirect through the paracrine effects of underlying stromal cells. The aim of this study was to test whether estradiol-17beta (E(2)) acts directly to regulate uterine epithelial cell monolayer integrity. METHODS OF STUDY: Mouse uterine epithelial cells were isolated and grown on cell culture inserts to form confluent, polarized monolayers, as indicated by the development of high transepithelial resistance (TER). RESULTS: When polarized epithelial cells were treated with E(2), TER was significantly decreased within 24 hr of exposure. Epithelial cells remained hormonally responsive in culture for at least 10 days. In contrast to estradiol, incubation with progesterone, cortisol, aldosterone, and DHT had no effect on uterine epithelial cell TER. The ability of E(2) to decrease TER was inhibited following co-incubation with ICI 182,780, a pure estrogen receptor antagonist. To further investigate the mechanism involved in estradiol-induced decreases in TER, we tested the effect of TAPI-0, an inhibitor of matrix metalloproteinases. Our findings indicate that TAPI-0 reversed the inhibitory effect of E(2) on TER. CONCLUSIONS: These studies demonstrate that epithelial monolayer integrity is directly influenced by E(2) and ER mediated. Further, it suggests that the mechanism through which estradiol decreases TER is mediated by matrix metalloproteinases.     

Social and sexual motivation in the mouse

Does a sexual encounter have reward value for a learned operant response? Ovariectomized female mice with or without estradiol replacement were trained to perform a bar-contact operant response for either male or female targets. Response rates of females with estradiol replacement did not differ from those of females without estradiol replacement or females responding for access to females. Reflexive receptive sexual behavior remained responsive to estradiol replacement. Experiment 2 demonstrated that socially isolated females would respond faster for access to a female target than when group housed. Finally, the oxytocin blocker, atosiban, reduced both operant and reflexive social behavior. These results converge on the conclusion that the operant reward value of social and sexual contact is primarily social.     

Lordosis behavior in males of two inbred strains of guinea pig

The lordosis behavior of male guinea pigs from inbred strains 2 and 13 was examined. Significantly more isolated gonadally intact males of strain 2 than strain 13 displayed lordosis. Castration did not decrease the display of lordosis. In castrated strain 2 males, those which showed lordosis did not have higher plasma androgen, estrone or estradiol levels than those which did not show lordosis. They also did not differ hormonally from ovariectomized strain 2 females even though strain 2 females never showed lordosis without hormone replacement. Although the lordosis shown by strain 2 males was not related to endogenous gonadal hormone levels, estradiol benzoate (EB) administration facilitated lordosis. EB had no clear effect on lordosis in strain 13 males. Progesterone after EB priming had no further facilitative effect in males of either strain. These results indicate that lordosis is more readily elicited from strain 2 than strain 13 males. Furthermore, lordosis in strain 2 males is not dependent upon gonadal hormones for its display although it is facilitated by EB (but not progesterone).     

成人循环内皮祖细胞的性别差异和雌二醇的体外动员作用

目的: 探讨成人循环内皮祖细胞(EPCs)数量及功能的性别差异、女性月经周期对其的影响和雌二醇的体外动员作用。方法: 选择月经周期正常的健康女性和年龄匹配的同等条件男性各10名,男性1次采血,女性在月经周期内3个性激素变化阶段(卵泡初期、排卵前期和黄体中期)分别采血。用流式细胞仪计数循环CD34⁺/CD133⁺/含有激酶插入结构域的受体(KDR)⁺的EPCs数量,放射免疫法测定雌二醇水平;经体外培养7 d,计数EPCs,并观察其黏附能力;分别通过跨膜迁移实验和增殖实验观察不同浓度雌二醇的影响。结果: 女性组循环EPCs数量明显高于男性组(P<0.01),月经周期内排卵前期和黄体中期明显高于卵泡初期(P<0.05)。经体外培养测定EPCs功能,男性与女性无明显差异。较高浓度的雌二醇(≥1×10^-9 mol/L)能显著增强EPCs的跨膜迁移能力和增殖能力(P<0.05)。结论: 成人循环EPCs数量存在性别差异并且受女性月经周期影响,雌二醇对EPCs的动员有重要作用。     

雌激素替代抑制萘诱导去卵巢大鼠的晶状体氧化损伤

背景：抗氧化作用可能是雌激素对晶状体保护作用的机制之一,但此机制的具体途径目前仍不明确,同时临床上常用的几种雌激素替代治疗方法对晶状体氧化损伤的影响至今少见报道。 目的：观察雌二醇及其联合孕酮对萘诱导去卵巢雌性大鼠晶状体氧化损伤模型中晶状体混浊情况、晶状体氧化防御系统、脂质过氧化产物及可溶性蛋白水平的影响。 方法：将SD大鼠随机分为假手术组、模型组、雌二醇组、雌二醇+孕酮组,后3组均行双侧卵巢切除。术后2周,4组均用萘混悬液灌胃,定期行裂隙灯显微镜检查观察各组大鼠晶状体变化;灌胃6周后检测晶状体氧化防御系统、脂质过氧化产物及可溶性蛋白水平,测定血清雌二醇和孕酮水平。 结果与结论：与模型组相比,雌二醇组、雌二醇+孕酮组及假手术组晶状体混浊程度轻,出现时间晚,而晶状体超氧化物歧化酶、谷胱甘肽、维生素C,可溶性蛋白含量,血清雌二醇与孕酮水平增高(P  < 0.05或P < 0.01),丙二醛水平降低(P < 0.05)。结果证实,雌二醇及其联合孕酮两种替代治疗方法对萘诱导去卵巢雌性大鼠晶状体的氧化损伤均有抑制作用,其机制与晶状体氧化防御系统的活性、抑制脂质过氧化产物的形成并维持可溶性蛋白的水平有关,抑制晶状体的氧化损伤是雌激素替代治疗发挥晶状体保护作用的机制之一。     

17β-雌二醇和二噁英对子宫内膜间质细胞表达趋化因子IL-8及其受体CXCR1的调控作用

解析内外环境因素对子宫内膜间质细胞表达IL-8及其自分泌作用的调控。采用免疫组化法比较子宫内膜异位症患者异位灶和在位内膜CXCR1翻译水平表达;流式细胞术分析17β-雌二醇和二噁英单独或联合作用对子宫内膜间质细胞表面CXCR1表达的调控作用;ELISA法分析17β-雌二醇和二噁英单独或联合作用对子宫内膜间质细胞分泌IL-8的影响。结果显示CXCR1在子宫内膜异位症患者异位灶组织高表达。17β-雌二醇和二噁英单独作用均抑制子宫内膜间质细胞表面CX-CR1的表达以及IL-8的分泌。二者联合作用能够上调CXCR1的表达,上调幅度与雌二醇浓度呈正相关;但进一步抑制了IL-8的分泌。雌激素与二噁英对子宫内膜间质细胞复合作用抑制其IL-8的分泌及其自分泌作用;子宫内膜异位症患者腹腔液高水平IL-8并非由内外雌激素样物质直接作用于异位灶子宫内膜间质细胞所致。     

17β-雌二醇和二噁英对子宫内膜间质细胞表达趋化因子IL-8及其受体CXCR1 的调控作用

解析内外环境因素对子宫内膜间质细胞表达IL-8及其自分泌作用的调控。采用免疫组化法比较子宫内膜异位症患者异位灶和在位内膜CXCRI翻译水平表达;流式细胞术分析17β-雌二醇和二嗯英单独或联合作用对子宫内膜间质细胞表面CXCRI表达的调控作用;ELISA法分析17β-雌二醇和二嗯英单独或联合作用对子宫内膜间质细胞分泌IL-8的影响。结果显示CXCRI在子宫内膜异位症患者异位灶组织高表达。17β-雌二醇和二嗯英单独作用均抑制子宫内膜间质细胞表面CX—CR1的表达以及IL-8的分泌。二者联合作用能够上调CXCR1的表达,上调幅度与雌二醇浓度呈正相关;但进一步抑制了IL-8的分泌。雌激素与二嗯英对子宫内膜间质细胞复合作用抑制其IL-8的分泌及其自分泌作用;子宫内膜异位症患者腹腔液高水平IL-8并非由内外雌激素样物质直接作用于异位灶子宫内膜间质细胞所致。