紫草素通过PI3K/Akt通路抑制氧糖剥夺诱导的大鼠原代皮层神经元凋亡

目的:探讨紫草素对氧糖剥夺(OGD)损伤模型中大鼠原代皮层神经元的作用及机制。方法:用不同浓度(0. 02、0. 2、2和20μmol/L)紫草素对大鼠原代皮层神经元经进行预处理,再经OGD损伤处理,用乳酸脱氢酶(LDH)释放法和荧光素二乙酸酯/碘化丙啶(FDA/PI)双染法分别检测神经元活性和凋亡情况,选择最适紫草素浓度。然后,在加入紫草素之前提前加入LY294002(PI3K/Akt信号通路抑制剂,1μmol/L),用Wesern blot法检测神经元p-Akt(Ser473)水平变化,用LDH法和FDA/PI双染法检测神经元活性和凋亡率变化。结果:0. 2、2及20μmol/L的紫草素可显著提高神经元存活率(P 0. 05),同时还可使神经元内p-Akt(Ser473)水平显著升高(P 0. 05); LY294002可显著阻断紫草素对神经元p-Akt(Ser473)水平和凋亡率的影响(P 0. 05)。结论:紫草素可通过激活PI3K/Akt通路来减少OGD诱导的大鼠原代皮层神经元凋亡。     

Shikonin protects chondrocytes from interleukin-1beta-induced apoptosis by regulating PI3K/Akt signaling pathway

Chondrocyte apoptosis is mostly responsible for the development and progression of osteoarthritis. IL-1β is generally served as an agent that induces chondrocyte apoptosis. Shikonin exerts its anti-inflammatory effect on cartilage protection in vivo. We aimed to explore the protective effect of shikonin on interleukin-1beta (IL-1β)-induced chondrocyte apoptosis and the potential molecular mechanisms. Chondrocytes were isolated from the joints of newborn Sprague-Dawley rats. The MTT assay and LDH cell death assay were used to determine the cell viability and chondrocyte apoptosis was detected by Annexin-V/PI staining and nucleosomal degradation. The contents of phosphorylated-PI3K (p-PI3k), phosphorylated-Akt (p-Akt), Bcl-2, Bax, and cytochrome c were detected by Western blotting. A quantitative colorimetric assay was used to detect the caspase-3 activity. Our results showed that pretreatment with shikonin (4 μM) inhibited cytotoxicity and apoptosis induced by IL-1β (10 ng/ml) in chondrocytes. Shikonin pretreatment also decreased the activity of IL-1β that decreased Bcl-2 expression and levels of p-PI3K and p-Akt, and increased Bax expression, cytochrome c release, and caspase-3 activation. It also reversed the activity of IL-1β that promoted the synthesis of matrix metalloproteinase-13 and inhibited the expression of tissue inhibitor of metalloproteinase-1 expression, with the net effect of suppressing extracellular matrix degradation. These data suggested that shikonin may protect chondrocytes from apoptosis induced by IL-1β through the PI3K/Akt signaling pathway, by deactivating caspase-3.     

The Inhibitory Effect of Shikonin on the Agonist-Induced Regulation of Vascular Contractility

Shikonin, a natural flavonoid found in the roots of Lithospermum erythrorhizon, has been shown to possess many biological functions. The present study was undertaken to investigate the influence of shikonin on vascular smooth muscle contractility and to determine the mechanism involved. Denuded aortic rings from male rats were used and isometric contractions were recorded and combined with molecular experiments. Shikonin significantly relaxed fluoride-, thromboxane A₂- or phorbol ester-induced vascular contraction suggesting as a possible anti-hypertensive on the agonist-induced vascular contraction regardless of endothelial nitric oxide synthesis. Furthermore, shikonin significantly inhibited fluoride-induced increases in pMYPT1 levels and phorbol ester-induced increases in pERK1/2 levels suggesting the mechanism involving the inhibition of Rho-kinase activity and the subsequent phosphorylation of MYPT1 and the inhibition of MEK activity and the subsequent phosphorylation of ERK1/2. This study provides evidence regarding the mechanism underlying the relaxation effect of shikonin on agonist-induced vascular contraction regardless of endothelial function.     

Natural Compound Shikonin Induces Apoptosis and Attenuates Epithelial to Mesenchymal Transition in Radiation-Resistant Human Colon Cancer Cells

Radiation resistance represents an imperative obstacle in the treatment of patients with colorectal cancer, which remains difficult to overcome. Here, we explored the anti-proliferative and migration-inhibiting properties of the natural product shikonin on a radiation-resistant human colon carcinoma cell line (SNU-C5RR). Shikonin reduced the viability of these cells in a dose-dependent manner; 38 μM of shikonin was determined as the half-maximal inhibitory concentration. Shikonin induced apoptotic cell death, as demonstrated by increased apoptotic body formation and the number of TUNEL-positive cells. Moreover, shikonin enhanced mitochondrial membrane depolarization and Bax expression and also decreased Bcl-2 expression with translocation of cytochrome c from mitochondria into the cytosol. In addition, shikonin activated mitogen-activated protein kinases, and their specific inhibitors reduced the cytotoxic effects of shikonin. Additionally, shikonin decreased the migration of SNU-C5RR cells via the upregulation of E-cadherin and downregulation of N-cadherin. Taken together, these results suggest that shikonin induces mitochondria-mediated apoptosis and attenuates epithelial-mesenchymal transition in SNU-C5RR cells.     

紫草素诱导消化系统肿瘤细胞凋亡的研究进展

紫草素是从中药紫草中提取的萘醌类化和物,具有抗炎、抗氧化、抗血小板、抗肿瘤等多种药理活性。紫草素能明显抑制肝癌、结肠癌、胃癌细胞的增殖并诱导其凋亡,而对正常细胞不良反应小,其作用机制包括激活胱天蛋白酶家族启动凋亡、引起Bcl-2蛋白酶家族表达变化从而促进细胞色素C的释放、诱导活性氧类的产生等。该文对紫草素诱导消化系统肿瘤细胞凋亡的作用及其机制进行综述。     

Shikonin derivatives inhibited LPS-induced NOS in RAW 264.7 cells via downregulation of MAPK/NF-kappaB signaling

AIM OF THE STUDY: Shikonin/alkannin (SA) derivatives, analogs of naphthoquinone pigments, are the major components of root extracts of the Chinese medicinal herb (Lithospermum erythrorhizon; LE) and widely distributed in several folk medicines. In the present study, the effect and the underline molecular mechanism of shikonin derivatives isolated from root extracts of Lithospermum euchroma on lipopolysaccharide (LPS)-induced inflammatory response were investigated. MATERIALS AND METHODS: Effects of five SA derivatives, including SA, acetylshikonin, beta,beta-dimethylacrylshikonin, 5,8-dihydroxy-1.4-naphthoquinone, and 1,4-naphthoquinone on LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in mouse macrophage RAW264.7 cells were examined. RESULTS: Data suggested that SA derivatives inhibited LPS-induced NO and PGE(2) production, and iNOS protein expression. RT-PCR analysis showed that SA derivatives diminished LPS-induced iNOS mRNA expression. Moreover, the phosphorylation of extracellular signal-regulated kinase (ERK)1/2 in LPS-stimulated RAW 264.7 cells was concentration-dependently suppressed by SA derivatives. SA inhibited NF-kappaB activation by prevention of the degradation of inhibitory factor-kappaB and p65 level in nuclear fractions induced by LPS. CONCLUSIONS: Taken together, these results suggest that the anti-inflammatory properties of SA derivatives might result from inhibition of iNOS protein expression through the downregulation of NF-kappaB activation via suppression of phosphorylation of ERK, in LPS-stimulated RAW 264.7 cells.     

紫草素对NZB／WF1小鼠狼疮性肾炎的疗效及其作用机制

目的探讨紫草素对NZB／WF1狼疮样小鼠的疗效及作用机制。方法将60只28周龄NZB／WF1狼疮样小鼠随机分为赋型剂组和紫草素低剂量组、高剂量组灌胃治疗14周．分别检测各组治疗前、后小鼠的尿蛋白和血。肾功能、抗双链DNA抗体、血清可溶性黏附分子,并观察各组小鼠肾组织病理学改变,同时采用RT—PCR法检测各组肾组织可溶性血管细胞黏附分子（VCAM一1）和可溶性细胞问黏附分子（ICAM一1）mRNA的表达水平。结果紫草素各组小鼠尿蛋白、血肾功能、血清可溶性黏附分子水平、肾组织VCAM一1和ICAM-1mRNA表达水平及肾小球损伤分级均较赋型剂组显著降低（均P〈0．05或0.01）。结论紫草素可减少NZB／WF1狼疮样小鼠尿蛋白水平,并可改善其肾功能和减轻肾脏病理损害,其作用机制可能与调节肾组织VCAM一1和ICAM一1mRNA表达水平有关。     

紫草素滴丸制备工艺的研究

目的:考察紫草素滴丸的制备工艺,设计正交实验,确定最佳工艺条件。方法:以聚乙二醇4000为基质,二甲基硅油为冷却剂,滴制工艺为:滴制温度85℃,冷却液5～25℃梯度冷却,滴距5cm,滴速40滴/min。结果:该工艺制得的滴丸圆整度好,丸重差异小,崩解时限为21 min,符合药典规定。结论:该工艺适合紫草素滴丸的制备。     

紫草油用于治疗早期压疮的疗效观察

目的研究探讨紫草油对早期压疮治疗的疗效观察。方法对50例早期压疮随机分为观察组和对照组,观察组采用紫草油进行治疗护理。结果25例压疮全部治疗有效,其中治愈24例,显效1例。结论紫草油治疗护理早期压疮疗程短、方法简单、疔效确切,值得在临床护理工作中推广应用。     

紫草素对口腔鳞癌Tca8113细胞增殖与凋亡的作用

目的：研究紫草素对体外培养的口腔鳞癌Tca8113细胞的增殖抑制及诱导凋亡作用。方法：采用四甲基偶氮唑蓝（MTT）法观察紫草素对Tca8113细胞的体外增殖抑制作用;采用光镜、透射电镜、琼脂糖凝胶电泳技术及流式细胞术观察紫草素对Tca8113细胞凋亡的影响。采用SPSS12．0软件包对数据进行单因素方差分析及t检验。结果：MTr检测显示．紫草素在0-50μmol／L浓度范围内。对Tca8113细胞的增殖抑制作用呈现时间依赖性和浓度依赖性（P〈0．01）．电镜下可见典型的细胞核皱缩及凋亡小体,DNA琼脂糖凝胶电泳观察到典型梯状条带,流式细胞仪结果显示亚G1期细胞明显增加,各组细胞凋亡率均显著高于对照组（P〈0．01）。结论：紫草素对口腔鳞癌Tca8113细胞具有明显的增殖抑制及诱导凋亡作用．可用于口腔鳞癌化学防治的新尝试。