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。     

基于TNFR/RIPK1通路探索紫草素对大鼠脊髓损伤的作用及机制

目的:初步探讨紫草素对大鼠急性脊髓损伤(spinal cord injury,SCI)后神经功能恢复的影响及作用机制。方法:将96只Sprague-Dawley(SD)雄性大鼠分为4组:假手术组,即A组;假手术+紫草素组,即B组;脊髓损伤+二甲基亚砜(dimethyl sulfoxide,DMSO)组,即C组;脊髓损伤+紫草素组,即D组;每组24只。C、D组采用钳夹法制作大鼠急性SCI 模型。所有大鼠硬膜下置管,A 组不给药,B组和D组造模后30 min 经导管注射紫草素100 mg·kg^-1,C组注射等量 DMSO,每日1次,至取材时间点。各组分别于造模后6、12 h和3 d 每组取8只大鼠,行 Basso-Beattie-Bresnahan(BBB)评分及造模后1、3、7、14、21 d行斜板实验,再处死动物取脊髓组织。造模后1 h 每组大鼠腹腔注射碘化丙啶(propidine iodide,PI)1 mg·kg^-1,术后24 h取材检测脊髓组织 PI 红染细胞数;24 h 时取材采用苏木素-伊红(haematoxylin eosin,HE)染色观察脊髓损伤情况,尼氏(Nissl)染色观察神经元存活数量,使用Western-blot技术检测 B细胞淋巴瘤-2(B cell lymphoma-2,Bcl-2)蛋白及凋亡相关蛋白受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)的表达水平。结果:造模后A组和B组各时间点的 BBB 评分均正常,C、D组各时间点均低于A、B组,D组造模后12 h和3 d的 BBB 评分高于同时间点C组(P<0.05)。造模后12 h,D组PI 红染细胞较C 组明显减少,神经元崩解减轻(P<0.05)。造模后24 h,A 组和 B 组脊髓组织 HE 和 Nissl 染色正常,D 组脊髓组织损伤程度和存活神经元数量均优于 C 组(P<0.05)。Bcl-2、RIPK1蛋白在A 组、B 组表达很低; RIPK1 在C组表达明显增高,在D组表达明显下降,差异有统计学意义(P<0.05);Bcl-2蛋白在D 组表达高于C 组(P<0.05)。结论:紫草素可减轻大鼠急性SCI后的病理变化,改善行为学评分,促进脊髓神经功能恢复。其具体机制可能与抑制TNFR/RIPK1信号通路介导的坏死性凋亡有关。     

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.     

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。     

紫草素对高糖诱导的血管内皮细胞凋亡和氧化应激的影响

目的:探讨紫草素(shikonin)对高浓度葡萄糖诱导的血管内皮细胞凋亡和氧化应激水平的影响及其可能的作用机制。方法:体外培养的大鼠胸主动脉内皮细胞随机分为5组:正常对照组(培养基中葡萄糖浓度为5.5 mmol/L)、高糖组(培养基中葡萄糖浓度为33 mmol/L)、高糖+低浓度紫草素组(培养基中葡萄糖浓度为33mmol/L,紫草素浓度为0.1μmol/L)、高糖+中浓度紫草素组(培养基中葡萄糖浓度为33 mmol/L,紫草素浓度为1μmol/L)和高糖+高浓度紫草素组(培养基中葡萄糖浓度为33 mmol/L,紫草素浓度为10μmol/L)。各组细胞经相应处理后,CCK-8法检测细胞活力,流式细胞术检测细胞的凋亡率;此外,检测细胞中丙二醛(malondialdehyde,MDA)、活性氧簇(reactive oxygen species,ROS)、超氧化物歧化酶(superoxide dismutase,SOD)及谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)的水平,以反映细胞的氧化应激状态;Western blot检测Nrf2/HO-1信号通路的活性。结果:相较于高糖组,紫草素处理可呈剂量依赖性地逆转高糖所致的内皮细胞活力降低及凋亡率增加。与正常对照组相比,高浓度葡萄糖可升高内皮细胞中MDA和ROS的含量,同时降低SOD和GSH-Px的活性;相较于高糖组,给予紫草素干预后,细胞内MDA和ROS的含量降低,SOD和GSH-Px的活性升高。此外,高糖可致内皮细胞中cleaved caspase-3、HO-1及核内Nrf2蛋白表达的增加;与高糖组相比,给予紫草素干预后细胞中cleaved caspase-3、HO-1和核内Nrf2的表达部分下降。结论:紫草素可显著改善高糖所致的血管内皮细胞凋亡,其作用机制可能与激活Nrf2/HO-1信号通路并降低细胞的氧化应激水平有关。     

紫草素对HGF诱导的人肺癌细胞上皮-间充质转化的逆转作用

目的:探讨紫草素(shikonin)对肝细胞生长因子(HGF)诱导的人非小细胞肺癌PC9细胞迁移、侵袭及上皮-间充质转化(EMT)的影响。方法:用HGF诱导PC9细胞建立EMT模型,采用不同剂量的shikonin干预24 h后,MTT法检测细胞活力;划痕愈合实验检测细胞的迁移能力;Transwell小室实验检测细胞的侵袭能力;Western blot法检测细胞中上皮型钙黏蛋白(E-cadherin)、神经型钙黏蛋白(N-cadherin)和波形蛋白(vimentin)的蛋白表达水平。结果:Shikonin可显著抑制PC9细胞的活力(P0.01),随着给药剂量的增加,shikonin对细胞的生长抑制率显著上升,并呈一定的剂量依赖关系,IC_(50)为9.364μmol/L。HGF可诱导PC9细胞发生迁移和侵袭;划痕愈合实验和Transwell小室实验显示,shikonin能明显抑制由HGF诱导的肺癌PC9细胞迁移和侵袭(P0.01)。Western blot检测结果显示HGF可诱导PC9细胞的EMT标志物E-cadherin蛋白表达下调,N-cadherin和vimentin蛋白表达上调,使其发生EMT;shikonin则可逆转由HGF诱导的PC9细胞E-cadherin蛋白表达下调及N-cadherin和vimentin蛋白表达上调(P0.01)。结论:Shikonin能逆转由HGF诱导的肺癌PC9细胞EMT,同时抑制其迁移和侵袭。