金雀异黄酮的抗血小板聚集作用及机制

目的观察金雀异黄酮对血小板聚集的影响,并初步探讨其作用机制。方法制备家兔富血小板血浆和贫血小板血浆,并通过加入不同浓度的金雀异黄酮,测定其对凝血酶和血小板活化因子(PAF)诱导的血小板聚集的抑制作用;并测定其对凝血酶的抑制率及PAF诱导聚集下的血栓素(TXB2)、6-酮-前列腺-F1α(6-Keto-PGF1α)的水平。结果金雀异黄酮能明显抑制由凝血酶和PAF诱导的血小板聚集,且金雀异黄酮与凝血酶有一定的亲和力,在PAF诱导的血小板聚集中,金雀异黄酮能明显降低TXB2水平,升高6-Keto-PGF1α水平。结论金雀异黄酮能够明显抑制由凝血酶和PAF诱导的血小板聚集,其作用与抑制凝血酶有一定关系外,可能与其通过调节PAF诱导聚集TXA2和PGI2的释放有关。     

染料木黄酮通过上调血红素氧合酶-1表达减缓野百合碱诱导的大鼠肺动脉高压

目的研究染料木黄酮对野百合碱诱导的肺动脉高压大鼠肺组织血红素氧合酶-1(heme oxygenase-1,HO-1)表达的影响,探讨其减缓肺动脉高压的可能机制。方法 40只雄性SD大鼠随机分成正常对照组(n=10)、野百合碱组(n=10)、小剂量染料木黄酮治疗组(20μg/kg;n=10)、大剂量染料木黄酮治疗组(80μg/kg;n=10)。监测血流动力学变化及通过电子显微镜观察肺小动脉结构重塑,Westernblot检测肺组织HO-1的表达。结果染料木黄酮治疗组较野百合碱组大鼠平均肺动脉压降低(P<0.01),右心肥厚指数下调(P<0.01),大剂量组更显著(P<0.01)。染料木黄酮治疗组较野百合碱组大鼠肺组织HO-1表达上调(P<0.01),大剂量组更显著(P<0.01)。结论染料木黄酮能减缓野百合碱诱导的大鼠肺动脉高压,可能与上调大鼠肺组织HO-1表达有关。     

The presence of monoiodinated derivates of daidzein and genistein in human urine and its effect on thyroid gland function

Dietary supplements used by women during menopause are usually based on plant extracts containing isoflavonoids, daidzein and genistein. Genistein is a known inhibitor of many enzymes, including thyroid peroxidase (TPO). In the thyroid follicle, genistein acts as its alternate substrate for the formation of genistein iodinated derivatives. The aim of this study was to search for daidzein- and genistein-iodinated derivatives in urine of isoflavonoid-supplemented women. Additionally, selected phytoestrogens, steroid and thyroid hormones before and after three months of phytoestrogen supplementation were estimated. Urinary levels of free phytoestrogen increased significantly after therapy. They ranged between 0.3–1600, 0.6–670 and 0–206 nmol/L for daidzein, genistein and S-equol, respectively. Monoiodinated derivatives of genistein were observed (0–504 pmol/L) in 60% of the investigated samples. Steroid and thyroid hormone levels were within the normal range and were not significantly altered. The presence of monoiodinated derivates in human urine confirmed that genistein and daidzein may enter human thyroid follicles and influence TPO. Since the levels of the free thyroid hormones were not affected, we propose that the use of phytoestrogen dietary supplements is not associated with the development of thyroid-gland disorders in subjects with adequate iodine intake.     

染料木素对2型糖尿病大鼠模型血糖的影响

目的研究淡豆豉中所提取的染料木素的降糖效果以及改善糖耐量的效果。方法利用链脲佐菌素注射液对喂以高脂饲料的SD大鼠进行注射,从而制作出2型糖尿病大鼠模型;随机将2型糖尿病大鼠分成4组,每组8只,即糖尿病模型组（Model）、二甲双胍干预组（MET）、染料木素低剂量干预组（Genlow）以及染料木素高剂量干预组（Genhigh）;将4组2型糖尿病大鼠按照一定要求分别处置,并测量血糖水平和糖耐量,与正常对照组（Control）进行对比;对胰腺组织HE染色进行显微观察。结果染料木素高剂量组显著降低了血糖水平达16.5左右,与糖尿病模型组及二甲双胍组比较差异具有统计学意义（P〈0.05）;改善了各时段糖耐量,与正常对照组及糖尿病模型组比较差异均具有统计学意义（P〈0.05）;对受损萎缩的胰岛B细胞有明显的修复作用,与糖尿病模型组比较具有显著性。结论染料木素可显著降低2型糖尿病大鼠的血糖水平,并改善其糖耐量,且对受损的胰岛B细胞有修复作用,使胰岛细胞表面的胰岛素受体数量增多。     

Genistein effects on stromal cells determines epithelial proliferation in endometrial co-cultures

Background

Estrogen is the leading etiologic factor for endometrial cancer. Estrogen-induced proliferation of endometrial epithelial cells normally requires paracrine growth factors produced by stromal cells. Epidemiologic evidence indicates that dietary soy prevents endometrial cancer, and implicates the phytoestrogen genistein in this effect. However, results from previous studies are conflicting regarding the effects of genistein on hormone responsive cancers.

Methods

The effects of estrogen and genistein on proliferation of Ishikawa (IK) endometrial adenocarcinoma cells were examined in co-cultures of IK cells with endometrial stromal cells, recapitulating the heterotypic cell-to-cell interactions observed in vivo. The roles of estrogen receptor (ER)α and ERβ were evaluated using ERα and ERβ specific agonists. ER activation and cell proliferation in the IK epithelial cells were determined by alkaline phosphatase assay and Coulter counter enumeration, respectively.

Results

Both estrogen and genistein increased estrogen receptor-induced gene activity in IK cells over a range of concentrations. Estrogen alone but not genistein increased IK proliferation in co-cultures. When primed by estrogen treatment, increasing concentrations of genistein produced a biphasic effect on IK proliferation: nM concentrations inhibited estrogen-induced proliferation while μM concentrations increased proliferation. Studies with an ERβ-specific agonist produced similar results. Genistein did not influence the effects of estrogen on IK proliferation in monoculture.

Conclusions

Our study indicates that nutritionally relevant concentrations (nM) of genistein inhibit the proliferative effects of estrogen on endometrial adenocarcinoma cells presumably through activation of stromal cell ERβ. We believe that sub-micromolar concentrations of genistein may represent a novel adjuvant for endometrial cancer treatment and prevention.     

Genistein对APP695转染PC12细胞凋亡的保护作用

目的观察Genisteint（GST）对APP695转染PCI2细胞凋亡的保护作用。方法将培养的PC12细胞分为正常对照组、APP695转染组、GST干预组。采用流式细胞术检测PC12细胞凋亡率。结果APP695转染组与正常对照组比较,PC12细胞存活率明显降低,凋亡率明显升高（P〈0,01）。GST干预组与APP695转染组比较,细胞存活率显著升高,凋亡率显著降低,其中1μmol／LGST组与APP695转染纽此较,细胞凋亡率降低（P〈0．05）,5μmol／LGST组较APP695转染组细胞凋亡率则明显降低（P〈0．01）。结论GST对APP695基因转染引起的PC12细胞损伤有一定的保护作用。     

Effects of genistein on hippocampal neurodegeneration of ovariectomized rats

To investigate the mechanism underlying the neurodegeneration of postmenopausal women, the effect of genistein on hippocampal neurodegeneration was investigated in ovariectomized (OVX) Sprague-Dawley rats. Three-month-old female Sprague-Dawley rats were randomly divided into four groups: sham operated; OVX only; genistein-treated OVX (OVX-genistein); and estradiol benzoate-treated OVX (OVX-EB). Genistein and EB were subcutaneously injected into rats of the OVX-genistein and OVX-EB groups, respectively, once a day from the second day after surgery. Behavioral testing began on day 31 after surgery and lasted 5 d. The activities of superoxide dismutase and content of malondialdehyde in serum, the concentration of intrasynaptosome-free calcium, membrane relative viscosity of cerebral synaptosomes, and mean optical density (MOD) of the hippocampal synaptophysin immunoreactivity product were measured, respectively, in the eighth week after surgery. It was found that the escape latency in the OVX-EB and the OVX-genistein groups was significantly lower than that in the OVX control group (p<0.05), whereas in the behavioral test, the platform-passing number was higher than in the OVX control group (p<0.05). [Ca²⁺] _i in the cerebral cortical and hippocampal synaptosome of the OVX-only group was remarkably higher than that in the other three groups (p<0.01). The hippocampal synaptosome membrane viscosity of the OVX-only group was significantly higher than that in the sham-operated, OVX-EB (p<0.05) and the OVX-genistein (p<0.01) groups. The MOD of synaptophysin immunoreactive product in the radiation layers of CA1, CA2, CA3 and the molecular layer of the dentate gyrus of the OVX-only group was significantly lower than in the sham-operated, OVX-genistein, and OVX-EB groups (p<0.01). These results suggested that genistein, which has antioxidant properties similar to estradiol, could be used as a substitute for estradiol to prevent or treat central neurodegeneration in postmenopausal women.     

Pharmacological postconditioning with the phytoestrogen genistein

Estrogens are known to activate the phosphatidyl-inosityl 3-kinase (PI3K)/Akt pathway, which is central in the cardioprotection afforded by ischemic postconditioning. Therefore, our goal was to investigate whether a phytoestrogen, genistein, could induce a pharmacological postconditioning and to investigate potential mechanisms. We used low doses of genistein in order to avoid tyrosine kinases inhibition. Thus, pentobarbital-anesthetized rabbits underwent a coronary artery occlusion followed by 4 h of reperfusion. Prior to reperfusion, they randomly received an i.v. injection of either saline (Control), 100 or 1000 microg/kg of genistein (Geni(100) and Geni(1000), respectively), and 10 or 100 microg/kg of 17beta-estradiol (17beta(10) and 17beta(100), respectively). Infarct size (IS, % area at risk) was significantly reduced in Gen(100), Gen(1000) and 17beta(100) but not in 17beta(10) (6+/-2, 16+/-5, 12+/-3 and 29+/-7%, respectively) vs. Control (35+/-4%). A significant decrease in the percentage of TUNEL-positive nuclei within infarcted area was observed in Gen(100) and 17beta(100) vs. Controls. The estrogen receptor antagonist fulvestrant (1 mg/kg i.v.) and the PI3K inhibitor wortmaninn (0.6 mg/kg) abolished the cardioprotective effect of genistein. Western blots also demonstrated an increase in Akt posphorylation in Gen(100). In the same group, in vitro mitochondrial swelling studies demonstrated a significant inhibition of calcium-induced opening of mitochondrial transition pore vs. Controls. In conclusion, genistein exerts pharmacological postconditioning with a similar potency as 17beta-estradiol through a pathway involving activation of the estrogen receptor, of PI3K/Akt and mitochondrial preservation. Therefore, genistein should not be only considered as an inhibitor of tyrosine kinase but also as a cardioprotective estrogen.     

Genistein对bFGF诱导的EJ细胞增殖的抑制作用

目的:观察碱性成纤维细胞生长因子(bFGF)对人膀胱癌细胞株EJ细胞的增殖作用;以及酪氨酸蛋白激酶(TPK)抑制剂Genistein对bFGF诱导的EJ细胞增殖的抑制作用。方法:以不同浓度的bFGF刺激EJ细胞,再对由bFGF引起的细胞增殖施加不同浓度的Genistein;以MTT法检测细胞的增殖程度,原位凋亡细胞检测(TUNEL)和流式细胞仪(FCM)检测Genistein对EJ细胞凋亡和细胞周期的影响。结果:bFGF可以使EJ细胞增殖比明显上升,Genistein可引起细胞增殖比明显下降,其程度均随浓度增高而增强;Genistein可以促进EJ细胞的凋亡,使细胞阻滞于G2/M期。结论:bFGF可以诱导EJ细胞的增殖,Genistein可以诱导EJ细胞凋亡,对bFGF诱导的细胞增殖有抑制作用,可能为膀胱肿瘤的治疗提供新的方法。