Quercetin protects cardiomyocytes against doxorubicin-induced toxicity by suppressing oxidative stress and improving mitochondrial function via 14-3-3γ

Cardiotoxicity limits the clinical applications of doxorubicin (Dox), which mechanism might be excess generation of intracellular ROS. Quercetin (Que) is a flavonoid that possesses anti-oxidative activities, exerts myocardial protection. We hypothesized that the cardioprotection against Dox injury of Que involved 14-3-3γ, and mitochondria. To investigate the hypothesis, we treated primary cardiomyocytes with Dox and determined the effects of Que pretreatment with or without 14-3-3γ knockdown. We analyzed various cellular and molecular indexes. Our data showed that Que attenuated Dox-induced toxicity in cardiomyocytes by upregulating 14-3-3γ expression. Que pretreatment increased cell viability, SOD, catalase, and GPx activities, GSH levels, MMP and the GSH/GSSG ratio; decreased LDH and caspase-3 activities, MDA and ROS levels, mPTP opening and the percentage of apoptotic cells. However, Que’s cardioprotection were attenuated by knocking down 14-3-3γ expression using pAD/14-3-3γ-shRNA. In conclusion, Que protects cardiomyocytes against Dox injury by suppressing oxidative stress and improving mitochondrial function via 14-3-3γ.     

Quercetin induces morphological and proliferative changes of rat’s uteri under estrogen and progesterone influences

This study investigated the effect of 10 or 100 mg/kg/day quercetin on the uterus of ovariectomized adult female rats receiving sex-steroid replacement regime mimicking changes in hormonal profiles during the reproductive cycle. Following seven days of treatment with estrogen and progesterone with or without quercetin, uteri were harvested for histological and proliferative cell nuclear antigen (PCNA) protein and mRNA expression and PCNA protein distribution analyses. Our findings indicated that co-administration of 10 mg/kg/day quercetin with estrogen and progesterone caused a significant decrease in the size of uterine lumen and epithelial heights with lower PCNA protein and mRNA expression as compared to estrogen plus progesterone-only treatment (P < 0.05). Concomitant treatment with estrogen and progesterone with 100 mg/kg/day quercetin resulted in a marked increase in the number of glands with increased PCNA protein and mRNA expression. Significantly higher PCNA distribution was observed in the stroma and glands as compared to estrogen plus progesterone-only treatment (P < 0.05). In conclusion, at 10 mg/kg/day, quercetin affects uterine morphology but not proliferation, however at 100 mg/kg/day, quercetin induced significant stromal and glandular proliferation which could predispose the uterus towards neoplastic development.     

槲皮素提取条件的优选

目的优选槲皮素的提取工艺。方法采用浸渍法和回流法从仙人掌中提取槲皮素。选择溶剂种类、浓度、回流提取时间和仙人掌粉末粒度4个因素,并以L9(34)正交设计安排实验。结果最佳回流提取工艺为:过60目筛的干燥仙人掌粉末加95%甲醇回流3h。结论回流提取的效率高于浸渍提取。     

槲皮素通过p53-p21-Rb通路缓解慢性阻塞性肺疾病的肺衰老

目的 探讨槲皮素对慢性阻塞性肺疾病(COPD)小鼠肺衰老的治疗作用及机制。方法 将30只C57BL/6小鼠随机分为对照组、模型组、槲皮素组,每组10只。模型组和槲皮素组采用烟熏联合气道内滴注脂多糖(LPS)的方法构建COPD小鼠模型。造模成功后,槲皮素组给予槲皮素(50 mg/kg)灌胃,1次/d,持续4周;对照组和模型组给予等体积生理盐水。采用苏木精-伊红(HE)染色法观察小鼠肺组织病理改变,并评估肺部病理损伤;采用衰老相关β-半乳糖苷酶(SA-β-gal)染色法观察小鼠肺组织的衰老状况;采用免疫组化法检测肺组织中凋亡相关蛋白Bcl-2、Bax表达情况;采用蛋白质印迹(Western blot)法检测肺组织中衰老相关蛋白p53、p21、Rb表达水平。结果 与对照组比较,模型组小鼠肺组织病理损伤明显,SA-β-gal染色的阳性面积明显增加,肺组织中Bcl-2蛋白表达减少、Bax蛋白表达增多,衰老相关蛋白p53、p21、Rb表达水平明显升高(均P<0.05);与模型组比较,槲皮素组小鼠肺组织病理损伤减轻,SA-β-gal染色阳性面积减少,肺组织中Bcl-2蛋白表达增高、Bax蛋白表...     

槲皮素对人卵巢癌SKOV-3细胞增殖的影响

 目的：探讨槲皮素对人卵巢癌SKOV-3细胞增殖抑制和凋亡的影响,为卵巢癌临床治疗提供依据。方法：不同浓度槲皮素处理卵巢癌SKOV-3细胞后,采用MTT实验检测细胞增殖抑制作用并计算抑制率,细胞免疫化学染色法鉴定细胞凋亡,流式细胞术检测细胞周期及细胞凋亡。结果：槲皮素能够抑制SKOV-3细胞的增殖,且呈时间和剂量依赖性,免疫荧光显示槲皮素对SKOV-3细胞具有诱导凋亡作用,流式细胞术显示SKOV-3细胞被阻滞在S期, G2/M期细胞比例降低,凋亡率上升。结论：槲皮素在体外能够抑制卵巢癌SKOV-3细胞的增殖,阻止细胞由S期向G2期移行,促进其凋亡。     

槲皮素对小鼠T细胞体外活化的抑制作用

目的:通过分析槲皮素对淋巴细胞早期活化标记物CD69表达的影响,探讨其对T淋巴细胞体外活化抑制作用的机制。方法:分离小鼠淋巴结细胞,加入多克隆刺激剂及槲皮素共同培养,分别于2、6、24h收获细胞,进行双色免疫荧光标记,以流式细胞仪对T细胞的CD69分子表达情况进行分析并计算抑制率。结果:槲皮素(终浓度10μmol/L)对未受刺激的T细胞CD69表达百分率无明显影响,而经佛波醇酯(PDB)及刀豆蛋白A(ConA)活化同时加入槲皮素的T细胞CD69表达百分率在2h、6h及24h均显著下降(P＜0.01)。槲皮素对PDB的抑制率随作用时间延长而明显下降,对ConA的抑制率平缓而持久。结论:槲皮素对PDB、ConA活化的T淋巴细胞均显示明显的抑制效应,表明该药可能作用于T细胞活化信号传递通路蛋白激酶Cθ或其下游部位,并且,这种抑制效应表现出一定的可逆性。     

槲皮素对镉致大鼠急性肾损伤预防作用的研究

目的研究镉致急性肾损伤中肾脏的病理和临床改变及槲皮素的预防作用。方法雄性Wistar大鼠随机分成对照组和预防组。测定肾损伤指标:血尿素氮(BUN)、尿乙酰氨基葡糖苷酶(NAG)、尿γ-L-谷氨酰转肽酶(γ-GT)、尿蛋白含量。光镜及透射电镜下观察肾脏病理改变。结果槲皮素预防组与对照组相比,大鼠的一般状态较好。预防组与对照组相比,肾脏病理损伤相对减轻且肾损伤指标含量显著降低,各组间比较差异具有统计学意义(P<0.01)。结论镉能够导致肾损伤,槲皮素对镉性肾损伤具有一定的预防作用。     

东北不同产地野生罗布麻叶总黄酮含量及抗氧化性比较

目的 测定东北松嫩草原和辽河入海口野生罗布麻叶总黄酮和槲皮素含量,并对其抗氧化活性进行比较.方法 超声波辅助提取总黄酮,比色法和HPLC分别测定总黄酮和槲皮素含量,DPPH·和·OH清除法评价抗氧化活性.结果 松嫩草原和辽河入海口罗布麻叶总黄酮含量分别为10.593～11.001mg·g-1,11.203mg·g-1;槲皮素含量分别为5.507～5.753mg·g-1,5.218mg·g-1.松嫩草原罗布麻叶总黄酮抗氧化活性较强.结论 辽河入海口和松嫩草原野生罗布麻叶总黄酮、槲皮素含量差异不显著,松嫩草原野生罗布麻叶总黄酮具有较强的抗氧化活性.     

槲皮素抑制乳腺癌发生及增殖的实验研究

目的 探讨槲皮素抑制乳腺癌发生及增殖的作用。方法 建立三甲基苯丙蒽（DMBA）诱导的乳腺癌动物模型。79只雌性SD大鼠随机分为A组（DMBA）、B组[DMBA 三苯氰胺（TAMC)],C组（DMBA＋槲皮素）及D组（空白对照）。持续喂养28周,经光镜、电镜观察,抗PCNA及H－ras免疫组化分析。结果 （1）A组大鼠乳腺肿瘤发生率为76．2％,明显高于B组（40．9％）、C组（45．5％）及D组（0％）,P＜0．05;B组与C组相比差异无显著性意义（P＞0．05）。（2）A组大鼠乳腺癌平均直径2．37cm,明显大于B组（1．82cm)及C组（1．71cm),P＜0．05;B组和C组相比差异无显著性意义（P＞0．05）。（3）PCNA免疫组化染色显示;A组和B组和C组相比差异有显著性意义（P＜0．05）;B组和C组相比差异无显著性意义（P＞0．05）。（5）H－ras免疫化染色显示;A组与B组和C组比较差异有显著性意义（P＜0．05）,B组和C组相比差异无显著性意义（P＞0．05）。结论 槲皮素有降低DMBA诱导的SD大鼠乳腺癌发生率及抑制肿瘤生长的作用,其机理可能与抑制ras基因活性、阻抑细胞增殖有关。     

The effect of quercetin on topotecan cytotoxicity in MCF-7 and MDA-MB 231 human breast cancer cells

BACKGROUND: Topotecan, which is a Camptothecin derivative, shows a large spectrum in anti-tumor activity. Topotecan exerts its cytotoxic effect on tumor cells mainly by inhibition of topoisomerase I activity resulting in double-strand DNA breaks. In our study, we investigated the combined cytotoxic action of Topotecan and Quercetin in MCF-7 and MDA-MB 231 human breast cancer cells. To examine the possible relation between the cytotoxic activity of Topotecan and oxidative stress, we measured ROS and nitrite levels in both human breast cell lines. MATERIALS AND METHODS: MCF-7 and MDA-MB 231 cells were exposed to Topotecan, Quercetin, or a combination of both agents for 24 h at 37 degrees C. The viability of the cells was measured using the colorimetric MTT (3-(4,5)-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. We determined reactive oxygen species and nitrite levels as indicators of oxidative stress in both cell lines with and without Topotecan and/or Quercetin incubations using fluorometric dichlorofluorescin diacetate (DCFH-DA) and diaminonaphtalene (DAN) assay. RESULTS: The IC(50) concentration of Topotecan was 100 ng/ml in MCF-7 cell line and 160 ng/ml in MDA-MB231 cell line. Treatment with Quercetin enhanced cytotoxicity of Topotecan as 1.4-fold in MCF-7 and 1.3-fold in MDA-MB-231 cell line. A significant increment on ROS and nitrite levels was found in MCF-7 and MDA-MB-231 cells following Topotecan incubation. CONCLUSIONS: Our results suggest that Topotecan has cytotoxic activity against both of the breast cancer cell lines in vitro. A combination with Quercetin increases efficacy of Topotecan in the treatment of breast cancers. Our results indicate that increased oxidative stress plays a role in the cytotoxic action of Topotecan.