Investigation of the Renal Protective Effect of Combined Dietary Polyphenols in Streptozotocin-Induced Diabetic Aged Rats

Natural polyphenols are widely reported to have a large range of pharmacological properties, especially antioxidant activities and free radical scavenging capacities. In this study, we investigate the effects of naringin, chlorogenic acid, and quercetin mixtures (NCQ) on renal fibrosis in streptozotocin (STZ)-induced diabetic aged rats and its underlying mechanisms for ten consecutive weeks. The oxidative defense system in the kidneys of treated rats was found to be improved. Several biomarkers were investigated including the blood urea nitrogen, creatinine, and uric acid. Moreover, antioxidant parameters were evaluated and we found that superoxide dismutase, catalase, glutathione peroxidase, Na⁺-K⁺-ATPase activities, the nitric oxide production, the protein carbonyl, the advanced oxidation protein products, lipid peroxidation, and reduced glutathione levels were all significantly balanced and close to control values. In addition, NCQ restored renal injuries and fibrosis as assessed by histological method and molecular biology investigation of the matrix metalloproteinase, the transforming growth factor-beta TGF-β, the tumor necrosis factor TNFα, and p53 expression. Our study proposes the NCQ combination as potential plant-derived bioactive compounds to prevent diabetic nephropathy.     

Dried Plum’s Polyphenolic Compounds and Carbohydrates Contribute to Its Osteoprotective Effects and Exhibit Prebiotic Activity in Estrogen Deficient C57BL/6 Mice

Evidence of dried plum’s benefits on bone continues to emerge. This study investigated the contribution of the fruit’s polyphenol (PP) and carbohydrate (CHO) components on a bone model of postmenopausal osteoporosis to explore their prebiotic activity. Osteopenic ovariectomized mice were fed diets supplemented with dried plum, a crude extract of dried plum’s polyphenolic compounds, or the PP or CHO fraction of the crude extract. The effects of treatments on the bone phenotype were assessed at 5 and 10 weeks as well as the prebiotic activity of the different components of dried plum. Both the CHO and PP fractions of the extract contributed to the effects on bone with the CHO suppressing bone formation and resorption, and the PP temporally down-regulating formation. The PP and CHO components also altered the gut microbiota and cecal short chain fatty acids. These findings demonstrate that the CHO as well as the PP components of dried plum have potential prebiotic activity, but they have differential roles in mediating the alterations in bone formation and resorption that protect bone in estrogen deficiency.     

Tea drinking and risk of pancreatic cancer

Background Epidemiologic studies have reported inconsistent results regarding tea consumption and the risk of pancreatic cancer. This study aimed to investigate whether tea consumption is related to the risk of pancreatic cancer. Methods We searched Medline, EMBASE, ISI Web of Science, and the Cochrane library for studies published up to November 2013. We used a meta-analytic approach to estimate overall odds ratio （OR） and 95% confidence interval （CO for the highest versus the lowest tea consumption categodes. Results The summary OR for high versus no/almost never tea drinkers was 1.04 （95% CI： 0.91-1.20）, with no significant heterogeneity across studies （P=0.751;/2=0.0%）. The OR was 0.99 （95% CI： 0.77-1.28） in males and 1.01 （95% CI： 0.79- 1.29） in females. The OR was 1.07 （95% CI： 0.85-1.34） in Asian studies, 1.05 （95% CI： 0.84-1.31） in European studies, and 0.98 （95% CI： 0.72-1.34） in the US studies. The OR was 0.87 （95% CI： 0.69-1.10） without adjustment for a history of diabetes and 1.16 （95% CI： 0.97-0.39） after adjustment for a history of diabetes. The OR was 0.90 （95% CI： 0.72-1.12） without adjustment for alcohol drinking and 1.16 （95% CI： 0.96-1.39） after adjustment for alcohol drinking. The OR was 0.97 （95% CI： 0.76-1.25） without adjustment for BMI and 1.07 （95% CI： 0.87-1.31） after adjustment for BMI. Conclusion This systematic meta-analysis of cohort studies dose not provide quantitative evidence that tea consumption is appreciably related to the risk of pancreatic cancer, even at high doses.     

葡茶多酚对尿酸诱导的肾小管上皮细胞TGF-β1表达的影响

目的研究葡茶多酚对尿酸诱导的肾小管上皮细胞TGF-β1表达的影响。方法培养分离肾小管上皮细胞,分对照组、尿酸组、葡茶多酚组（在尿酸干预基础上,分别加入终浓度为0．2、0．4、0．8mg／L的葡茶多酚）共5组,MTT法测细胞增生率、TUNEI。测凋亡率、ELISA测TGF-β1分泌,RT-PCR测TGF-β1mRNA表达。结果与尿酸组相比,加入葡茶多酚干预后,肾小管上皮细胞增生率明显增高（P〈0．01）,葡茶多酚干预浓度愈高,肾小管上皮细胞增生率则愈高;葡茶多酚各浓度组在任一时间点凋亡率均明显低于尿酸组,差异有显著意义;葡茶多酚各浓度组之间相比,浓度愈高,则培养细胞凋亡率愈低,差异有显著意义,尿酸作用时间愈长,则培养细胞凋亡率愈高;葡茶多酚各浓度组在任一时间点培养上清TGF-β1浓度均明显降低,差异有显著意义;葡茶多酚各浓度组之间相比,浓度愈高,则培养上清TGF-β1浓度愈低,差异有显著意义,尿酸作用时间愈长,则培养上清TGF-β1浓度愈高;葡茶多酚各浓度组在任一时间点培养上清TGF-β1mRNA表达均明显降低,差异有显著意义;葡茶多酚各浓度组之间相比,浓度愈高,则培养上清TGF-β1mRNA表达愈低,但0．2mg／L葡茶多酚组与0．4mg／L葡茶多酚组、0．4mg／L葡茶多酚组与0．8mg／L葡茶多酚组差异无显著意义,0．2mg／L葡茶多酚组与0．8mg／L葡茶多酚组之间差异有显著意义,尿酸作用时间愈长,则TGF-β1mRNA表达愈高。结论高尿酸能抑制肾小管上皮细胞的增生,减少肾小管上皮细胞的凋亡及TGF-β1的表达与分泌。     

超声波辅助乙醇提取山葡萄籽多酚的工艺研究

目的：确定超声波辅助乙醇提取山葡萄籽多酚的最佳工艺条件,为山葡萄籽的利用提供技术参考。方法：以山葡萄籽为原料,乙醇为提取液,通过单因素实验与正交试验设计,检测在不同乙醇浓度（20%、40%、60%、80%和95%）、提取时间（10、20、30、40和60 min）、提取温度（25℃、35℃、45℃、55℃和65℃）、料液比（1：4、1：6、1：8、1：10和1：12）、提取次数（1、2、3、4和5次）及超声功率（50、60、80、100和120W）时山葡萄籽多酚的提取率。结果：超声波辅助乙醇提取山葡萄籽多酚的最佳工艺参数为乙醇浓度60%、提取温度50℃、提取时间30 min、超声功率120W、料液比1：8,提取2次。在此工艺参数下,山葡萄籽多酚得率为11.71%,多酚含量为32.86%。结论：与传统溶剂浸提法比较,超声波辅助乙醇提取山葡萄籽多酚更具优势,该工艺具有简单、合理和高效的特点。     

茶多酚对大鼠睾丸扭转/复位模型保护作用的研究

目的:探讨茶多酚对大鼠睾丸扭转/复位模型的保护作用。方法:将24只健康雄性Wistar大鼠随机分为3组,每组8只。第Ⅰ组为假手术组(切开左侧阴囊游离睾丸,但不予扭转),第Ⅱ、Ⅲ组扭转左侧睾丸720°6h,分别于扭转复位前30min腹腔注射生理盐水和茶多酚,术后连续3d分别以低剂量维持。3组大鼠喂养至术后第5天处死,切取左侧扭转睾丸检测睾丸组织中超氧化物歧化酶(SOD)和丙二醛(MDA)含量;以原位缺口末端标记法(TUNEL)检测生精细胞凋亡指数(AI)。结果:Ⅰ、Ⅱ、Ⅲ3组左侧扭转睾丸组织SOD活力分别为(285.00±22.51)、(242.00±17.62)、(261.00±10.01)nU/mg;MDA含量分别为(1.81±0.20)、(4.34±0.34)、(2.94±0.38)nmol/mg;3组之间比较均有显著性差异。Ⅰ、Ⅱ、Ⅲ3组左侧扭转睾丸生精细胞凋亡指数(AI)分别为6.64±1.82、55.23±6.46、31.84±5.56,第Ⅲ组与第Ⅱ组相比,其生殖细胞凋亡明显减少(P<0.05)。结论:茶多酚对因睾丸扭转导致的缺血再灌注损伤具有保护作用。     

茶多酚对5500m低压条件下吸纯氧引起的小鼠心肌自由基代谢异常的保护作用

目的 观察天然抗氧化剂茶多酚（Tea Polyphenols,TP)对模拟飞行低压吸纯氧引起的小鼠心肌自由基代谢异常的保护作用。方法 42只雄性昆明种小鼠随机分为3组（n=14):对照组（A）、5500m低压吸氧组（B）和TP保护组（C）。B、C两组置于动物低压舱在5500m低压下吸氧（＞96％）,2h/d,3d/wk,共8wk。上舱暴露前,C组灌胃给予TP100mg/kg,另2组给予蒸馏水。末次实验后次日将小鼠断头处死,迅速取出心肌组织。测定心肌超氧化物歧化酶（SOD）活性和丙二醛（MDA）、一氧化氮（NO）含量。另外,用免疫组化法对心肌组织Cu,Zn-SOD和诱生型NO合酶（iNOS)的含量进行定性观察。结果 与对照比较,B组MDA水平、SOD添性和Cu,Zn-SOD酶含量明显升高（P＜0．05）;TP有明显保护作用：降低MDA生成（P＜0．01）,SOD活性和含量恢复正常。与之相反,重复5500m低压吸氧暴露后,心肌NO含量和iNOS表达明显降低。重复给予TP使NO代谢恢复正常。结论 天然抗氧化剂茶多酚对模拟飞行低压吸纯氧引起的心肌自由基代谢异常具有保护作用。     

绿茶多酚改善环孢素A抑制血管舒张的作用

目的 观察绿茶多酚(GTP)对环孢素A(CsA)抑制血管舒张作用的改善,并探讨其机制.方法 将30只SD大鼠随机平均分为3组:CsA组、对照组和CsA+GTP组.建模5周后,检测体质量、肾功能:血尿素氮(BUN)、肌酐(Cre);并取胸主动脉环,观察乙酰胆碱(Ach)诱发的血管舒张反应、左旋硝基精氨酸甲酯(L-NAME)和吲哚美辛预处理对舒张反应的影响、去内皮细胞的血管舒张反应.并检测血管组织一氧化氮(NO)水平.结果 实验5周后,CsA组大鼠体质量(253.2±8.1)g低于对照组(292.1±9.5)g;CsA+GTP组体质量(287.9±9.7)g高于CsA组;CsA组BUN、Cre含量高于对照组;CsA+GTP组BUN、Cre低于CsA组;差异均有统计学意义(P<0.05).CsA组大鼠Ach引起的动脉环的最大舒张度为(42.5±4.3)%,低于对照组的(81.2±7.6)%和CsA+GTP组的(70.1±6.5)%,差异有统计学意义(P<0.05).用L-NAME预处理后,CsA组和CsA+GTP组动脉环的舒张幅度分别为(40.3±3.7)%和(45.8±4.2)%,均低于对照组的(79.4±6.8)%;用吲哚美辛预处理后对照组和CsA+GTP组的舒张反应高于CsA组;差异均有统计学意义(P<0.05).去内皮细胞的各组血管中,血管舒张反应被明显抑制,各组血管的舒张百分比差异无统计学意义(P>0.05).CsA组大鼠血管组织中NO含量显著低于对照组和CsA+GTP组,差异有统计学意义(P<0.05).结论 CsA可导致血管组织NO水平下降,引起NO介导的内皮依赖性血管舒张功能异常.应用绿茶多酚后,则升高其血管组织中NO水平,改善内皮依赖性的血管舒张功能.     

Cavernous antioxidant effect of green tea,epigallocatechin‐3‐gallate with/without sildenafil citrate intake in aged diabetic rats

This study aimed to assess the cavernous antioxidant effect of green tea (GT), epigallocatechin‐3‐gallate (EGCG) with/without sildenafil citrate intake in aged diabetic rats. One hundred and four aged male white albino rat were divided into controls that received ordinary chow, streptozotocin (STZ)‐induced aged diabetic rats, STZ‐induced diabetic rats on infused green tea, induced diabetic rats on epigallocatechin‐3‐gallate and STZ‐induced diabetic rats on sildenafil citrate added to EGCG. After 8 weeks, dissected cavernous tissues were assessed for gene expression of eNOS, cavernous malondialdehyde (MDA), glutathione peroxidase (GPx), cyclic guanosine monophosphate (cGMP), and serum testosterone (T). STZ‐induced diabetic rats on GT demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats. Diabetic rats on EGCG demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats or diabetic rats on GT. Diabetic rats on EGCG added to sildenafil showed significant increase in cavernous eNOS, cGMP and significant decrease in cavernous MDA compared with other groups. Serum T demonstrated nonsignificant difference between the investigated groups. It is concluded that GT and EGCG have significant cavernous antioxidant effects that are increased if sildenafil is added.     

茶多酚改善大鼠缺血/再灌注心脏功能和能量代谢并抑制体外培养心肌细胞的钙内流

目的：探讨茶多酚对缺血/再灌注心脏损伤的保护作用,并研究心脏能量代谢和心肌细胞钙内流是否参与了心脏缺血/再灌注损伤的保护作用。方法在大鼠Langendorff离体心脏上实施缺血/再灌注各30 min,用一导管经压力换能器连接放大器记录心功能指标;用31P NMR技术测定心脏的能量代谢,全细胞膜片钳技术记录心肌细胞钙内流。结果与对照组比较,茶多酚（2.5 mg/L）能使缺血/再灌注心脏的心室发展压、左心室压最大收缩速率（+dp/dtmax）、左心室压最大舒张速率（-dp/dtmax）和冠脉流量显著增加（P<0.05）,并显著改善缺血/再灌注心脏的能量代谢,增加心肌ATP和PCr含量（P<0.05）。浓度为2.5和5.0 mg/L的茶多酚均能显著抑制培养心肌细胞的钙内流（P<0.01）。结论茶多酚对大鼠离体心脏缺血/再灌注损伤的保护作用可能与其改善心肌能量代谢、抑制心肌细胞钙内流的作用有关。