白藜芦醇预防性给药诱导裸鼠胃癌移植瘤细胞凋亡的观察

目的研究白藜芦醇预防性给药诱导裸鼠胃癌移植瘤细胞凋亡的作用。方法用胃癌MGC-803细胞株建立裸鼠胃癌移植瘤模型,通过白藜芦醇预防性给药,采用瘤体体积计算、透射电镜及原位末端标记染色（TUNEL）方法观察不同剂量白藜芦醇对裸鼠胃癌移植瘤的生长和细胞凋亡的影响。所有数据均以（x±s）表示,数据分析采用SPSS13.0软件,多组间均数比较采用单因素方差分析,用SNK-q检验进行两两比较,P〈0.05为差异有统计学意义。结果白藜芦醇中、高剂量组能明显抑制裸鼠胃癌移植瘤的生长,抑制率达到49.38%（P〈0.05）;电镜观察白藜芦醇各用药组出现凋亡细胞的典型形态;TUNEL法检测模型组、白藜芦醇低、中和高剂量组的凋亡细胞阳性表达率（%）分别为（14.254±4.344）,（31.270±4.461）,（44.082±3.436）和（58.809±4.060）（P〈0.01）,随着白藜芦醇用药剂量的增加,肿瘤细胞凋亡率上升。结论通过预防性给药,白藜芦醇能够抑制裸鼠胃癌移植瘤的生长,诱导裸鼠胃癌移植瘤细胞发生凋亡。     

白藜芦醇对大鼠脑创伤后TNF-α和IL-1β影响的实验研究

目的检测白藜芦醇治疗后脑创伤大鼠血清TNF-α和IL-1β的浓度变化,探讨白藜芦醇的脑保护作用。方法SD大鼠50只,随机分为对照组和治疗组,每组分伤后3h、12h、24h、48h、72h共5个时间点,各时间点每组动物5只。Feeney法自由落体致伤动物。治疗组给予白藜芦醇(50mg/kg体重)腹腔注射治疗,伤前1d治疗一次,伤后每天治疗一次;对照组同法给予等量生理盐水治疗。分别于伤后各时间点股静脉取血,静置分层后离心,取血清低温保存,放射免疫法检测血清TNF-α和IL-1β浓度。结果伤后治疗组TNF-α和IL-1β浓度比对照组明显降低。结论白藜芦醇可以降低伤后血清TNF-α和IL-1β浓度,对脑创伤有保护作用。     

白藜芦醇对辐射诱导调节T细胞紊乱的调节作用

目的观察电离辐射及白藜芦醇对调节T细胞的影响,探讨其对细胞因子TGF-β及IFN-γ的影响,阐明白藜芦醇对辐射诱导免疫抑制的改善作用。方法将24只C57BL/6雄性小鼠随机分为对照组、照射组和照射给药组,每组8只。照射组和照射给药组接受137Cs源γ射线全身照射(6.0 Gy),对照组小鼠接受伪照射。照射前7 d及照射后28 d,每日予白藜芦醇(20 mg/kg)灌胃。末次给药后1 d,检测各组小鼠外周血CD4+CD25+细胞数量,CD4+CD25+细胞内Fox P3表达水平,脾淋巴细胞TGF-β分泌水平,以及CD8+细胞及脾淋巴细胞TNF-γ表达水平。采用单因素方差分析对3组间的细胞比例及细胞因子表达水平进行比较,组间多重比较采用LSD-t检验。结果与正常小鼠比较,电离辐射可以增高CD4+CD25+细胞在外周血单核细胞和CD4+中的比例125.0%和57.2%,增高脾细胞TGF-β水平31.4%,降低脾细胞IFN-γ表达水平26.9%,组间差异均具有统计学意义(均P0.05);白藜芦醇干预可以降低单纯照射组小鼠调节T细胞在外周血单核细胞和CD4+中的比例32.3%和27.8%,降低CD4+CD25+细胞的Fox P3阳性比例26.6%,以及脾淋巴细胞TGF-β水平62.9%,增加CD8+T细胞及脾淋巴细胞生成的IFN-γ水平133.0%和87.4%,组间差异均具有统计学意义(均P0.05)。结论白藜芦醇可以抑制调节T细胞,改善受照小鼠的免疫功能。     

Protective effect of resveratrol on 5/6 nephrectomized rats and its mechanism

Objective To investigate the protective effect of resveratrol (RSV) on 5/6 nephrectomized rats and its mechanism. Methods Fifty male SD rats were randomly divided into three groups: sham operated (Sham, n＝10）, 5/6 nephrectomy (Nx, n＝20), and 5/6 nephrectomy＋RSV 20 mg/kg (Nx＋RSV, n＝20). RSV or normal saline was administered one week after 5/6 nephrectomy. Proteinuria was detected every 4 weeks. Serum creatinine and the renal pathological changes were measured after 12 weeks. Immunohistochemisty staining of fibronectin (FN), collagenⅠ, transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF) were used to analyze the changes of renal fibrosis. Western blotting was used to measure the expression of Smad3, phospho-Smad3, and acety-Smad3. Immunoprecipitation was used to detect the interaction between Sirt1 and Smad3. Results Compared with the sham operated rats, subtotal nephrectomy significantly increased proteinuria [(152.14±30.49) mg/24 h vs (25.34±7.54) mg/24 h], serum creatinine[(111.60±21.50) μmol/L vs (53.90±11.59) μmol/L], glomerular sclerosis index (1.56±0.34 vs 0.35±0.08) and the expressions of fibronectin, collagenⅠ, TGF-β and CTGF in renal tissue at 12 weeks after operation (all P＜0.01), and RSV treatment significantly inhibited the above up-regulations (all P＜0.01). Compared with the sham operated rats, subtotal nephrectomy increased the expression of phospholylation and acetylation of Smad3. RSV treatment significantly reduced the expression of acety-Smad3, but had no effect on the phospho-Smad3. Immunoprecipitation revealed a binding effect of Smad3 with Sirt1. Conclusions RSV treatment can attenuate proteinuria, protect renal function and inhibit renal fibrosis in 5/6 nephrectomized rats. This renal protective effect is associated with reduced Smad3 acetylation and activation of Sirt1, which suggesting that Sirt1 may be a potential therapeutic target of CKD.     

Resveratrol inhibits hypoxia-induced metastasis potential enhancement by restricting hypoxia-induced factor-1α expression in colon carcinoma cells

Resveratrol has been shown recently to exhibit antimetastatic effect on various human solid tumors. However, the possible molecular mechanism for its antimetastatic action needs to be elucidated. In this study, we investigated the effect of resveratrol on metastasis potential of colon carcinoma cells under normoxia and hypoxia in vitro. These results showed that, resveratrol can restrict the migration, adhesion, invasion and MMP-9 and MMP-2 secretion in Lovo cells cultured under normoxia and hypoxia. Hypoxia and iron chelator 2,2′-dipyridyl treatment can stimulate the invasion and migration enhancement of Lovo cells, while resveratrol exhibited substantial resistance on the metastasis potential stimulation by inhibiting the mRNA expression of VEGF and MMP-9 in colon carcinoma cells under normoxia and hypoxia, reducing HIF-1α protein expression under hypoxia. Also, iron chelator 2,2′-dipyridyl treatment showed approximately the same effect on metastasis potential as Lovo cells cultured under hypoxia. These data demonstrated that, the antimetastatic effect of resveratrol under hypoxia were associated with the restriction of HIF-1α protein expression and stabilization, which could be a promising drug target for resveratrol in the development of an effective chemopreventive and anticancer therapy in human tumors.     

Resveratrol,a natural phytoalexin,normalizes hyperglycemia in streptozotocin-nicotinamide induced experimental diabetic rats

Resveratrol is a polyphenolic phytoalexin produced in appreciable amounts as a secondary metabolite in grapevines in response to fungal infections. Based on the present knowledge, it appears to be a promising bioactive natural molecule with potential applications in phytotherapy or pharmacology. The present study was aimed to evaluate the antidiabetic properties of resveratrol in streptozotocin-nicotinamide induced experimental diabetes in rats. The diabetic rats orally treated with resveratrol (5 mg kg⁻¹ b.w d⁻¹) for 30 days resulted in significant (p < 0.05) decrease in the levels of blood glucose, glycosylated hemoglobin, blood urea, serum uric acid, serum creatinine and diminished activities of pathophysiological enzymes such as aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). The antihyperglycemic nature of resveratrol is also evidenced from the improvement in the levels of plasma insulin and hemoglobin. Further, the results are comparable with glyclazide, an oral standard drug. Thus, the present findings suggest that resveratrol may be considered as an effective therapeutic agent for the treatment of diabetes mellitus.     

Hepatoprotective effects of antioxidants in chronic hepatitis C

We have read with interest the paper published in issue 2, volume 16 of World Journal of Gastroenterology 2010 by Nakamura et al, demonstrating that the antioxidant resveratrol (RVT) enhances hepatitis C virus (HCV) replication, consequently, they conclude that RVT is not a suitable antioxidant therapy for HCV chronic infection. The data raise some concern regarding the use of complementary and alternative medicine since the most frequent supplements taken by these patients are antioxidants or agents that m...     

白藜芦醇在动脉粥样硬化治疗中的抗炎抗氧化及抗增殖作用研究进展

白藜芦醇是一种多酚类化合物,具有广泛的生理药理学作用,如抗炎症、抗氧化及抗增殖等多种生物活性,但目前其作用机制尚未完全明确。近年研究表明,白藜芦醇主要通过调控白细胞介素6/信号转导及转录活化因子3、核因子κB及分裂原活化蛋白激酶等关键信号转导通路达到其抗炎、抗氧化作用,主要通过抑制哺乳动物雷帕霉素靶蛋白信号通路作用达到其抗增殖作用。