褐藻糖胶对人乳腺癌MCF-7细胞的增殖抑制和凋亡诱导作用

目的：研究褐藻糖胶对体外培养的人乳腺癌MCF-7细胞增殖及凋亡的影响，并探讨其凋亡机制。方法:不同浓度(100 mg/L、300 mg/L、500 mg/L、1 000 mg/L)褐藻糖胶处理MCF-7细胞48h后，应用四甲基偶氮唑蓝（MTT）法检测细胞的增殖；Hoechst 33258染色、琼脂糖凝胶电泳法观察细胞的凋亡的形态学及生化改变；逆转录聚合酶链反应（RT-PCR）和蛋白印迹分别测定细胞〖STBX〗bcl-2〖STBZ〗和bax mRNA及其蛋白的表达。结果:不同实验浓度(100 mg/L、300 mg/L、500 mg/L、1 000 mg/L)的褐藻糖胶均能抑制MCF-7细胞的增殖（P<0.01），抑制率呈浓度依赖性增大；褐藻糖胶诱导MCF-7细胞凋亡数增加，且可见明显的、凋亡特有的DNA梯形条带；在褐藻糖胶存在下，〖STBX〗 bcl-2〖STBZ〗 mRNA和蛋白表达减少，而bax mRNA和蛋白表达增加，Bcl-2/Bax比值下降（P<0.05）。结论:褐藻糖胶可抑制MCF-7细胞增殖，且诱导其凋亡，其凋亡机制是下调Bcl-2和上调Bax蛋白的表达。     

Fucoidan Promotes the Reconstruction of Skin Equivalents

In this study we investigated the effects of fucoidan on the proliferation of fibroblasts and the reconstruction of a skin equivalent (SE). Fucoidan significantly stimulated the proliferation of CCD-25Sk human fibroblasts and Western blot analysis demonstrated that fucoidan markedly increased the expression of cyclin D1 and decreased the expression of p27. Fucoidan was used to reconstruct SE. Immunohistochemical staining showed that the addition of fucoidan to dermal equivalents increased expression of proliferating cell nuclear antigen (PCNA) and p63. In addition, expression of α6-integrin was significantly increased by fucoidan, whereas expression of β1-integrin, type 1 collagen, elastin, fibronectin did not markedly change. These results suggest that fucoidan has positive effects on epidermal reconstruction and will therefore be beneficial in the reconstruction of SE.     

Differential effects of fucoidans with low and high molecular weight on the viability and function of spleen cells

Fucoidan is an edible sulfated polysaccharide purified from brown algae that has multiple biological activities. However, the effects of fucoidans of different molecular weights on immune cells have not been determined. Thus, we treated spleen cells with low- and high-molecular-weight fucoidans (LMF and HMF, respectively). Viability assays demonstrated that HMF enhanced the viability and prevented the death of spleen cells. Furthermore, functional analysis revealed that HMF significantly increased the production of interferon-γ and nitric oxide. In contrast, LMF had low activity and was relatively toxic to spleen cells. Taken together, these results indicate that HMF makes the greatest contribution to the immunostimulatory activity of fucoidan mixtures. Additionally, fucoidans with different molecular weights may have different effects on the viability and function of immune cells. This study increases our understanding of fucoidans, and may broaden their use in the basic research and clinical fields.     

褐藻多糖硫酸酯对大鼠脑缺血再灌注损伤后的神经保护作用

目的探讨褐藻多糖硫酸酯（FPS）对脑缺血再灌注损伤的神经保护作用及可能机制。方法将48只大鼠按照随机数字表法分为假手术组、大脑中动脉栓塞（MCAO）组、FPS低剂量组（MCAO＋FPS 50 mg/kg）、FPS高剂量组（MCAO＋FPS 100 mg/kg）,每组12只。假手术组大鼠只分离右侧颈总动脉及颈内外动脉,MCAO组、FPS低剂量组、FPS高剂量组采用线栓法制作大脑中动脉栓塞模型,缺血2 h后再灌注后FPS低、高剂量组予鼠尾静脉注射FPS50、100 mg/kg。对所有大鼠按照Longa标准进行神经功能评分;采用TTC法测量脑梗死体积;蛋白印迹法测定Nrf2蛋白的表达。结果与MCAO组比较,FPS低、高剂量组大鼠神经功能评分明显降低、转录因子NF-E2相关因子2（NF-E2-related factor 2,Nrf2）蛋白表达明显增高,FPS高剂量组神经功能评分、Nrf2蛋白表达改变得更为显著（P〈0.05,P〈0.01）;FPS高剂量组大鼠脑梗死体积明显减小（P〈0.01）。结论 FPS通过提高Nrf2的表达缩小脑梗死体积,对脑缺血再灌注损伤大鼠起到神经保护作用。     

Fucoidan-induced ID-1 suppression inhibits the in vitro and in vivo invasion of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a fast growing tumor associated with a high tendency for vascular invasion and distant metastasis. Recently, we reported that fucoidan displays inhibitory effect on proliferation and invasion of HCC cells. In this study, we investigated the anti-metastatic effect of fucoidan on HCC cells and the key signal that modulates metastasis. The anti-metastatic effect of fucoidan was evaluated in vitro using an invasion assay with human HCC cells (Huh-7, SNU-761, and SNU-3085) under both normoxic (20% O₂ and 5% CO₂, at 37 °C) and hypoxic (1% O_2, 5% CO₂, and 94% N_2, at 37 °C) conditions. Complementary DNA (cDNA) microarray analysis was performed to find the molecule which is significantly suppressed by fucoidan. In vivo study using a distant metastasis model by injecting SNU-761 cells into spleen via portal vein was performed to confirm the inhibitory effect by small interfering RNA (siRNA) transfection. Immunoblot analyses were used to investigate the signaling pathway. Fucoidan significantly suppressed the invasion of human HCC cells (Huh-7, SNU-761, and SNU-3085). Using cDNA microarray analysis, we found the molecule, ID-1, which was significantly suppressed by fucoidan treatment. Downregulation of ID-1 by siRNA significantly decreased invasion of HCC cells, both in vitro and in vivo (both P < 0.05) in a NDRG-1/CAP43-dependent manner. In immunoblot assay, downregulation of ID-1 by siRNA decreased the expressions of epithelial-mesenchymal transition markers including CK19, vimentin, MMP2, and fibronectin. Immunofluorescence study also revealed that actin rearrangement was inhibited when ID-1 was down-regulated in HCC cells. Interestingly, in SNU-761 cells, the ID-1 expressions under hypoxic conditions were lower as compared to those under normoxic conditions. Under hypoxic conditions, HIF-1α up-regulated NDRG-1/CAP43, while HIF-2α down-regulated ID-1, which might be a compensatory phenomenon against hypoxia-induced HCC invasion. In conclusion, NDRG-1/CAP43-dependent down-regulation of ID-1 suppressed HCC invasion both in vitro and in vivo, which was modulated by fucoidan treatment. Moreover, the compensatory down-regulation of ID-1 against hypoxia-induced HCC invasion was observed. ID-1 is a novel therapeutic target for the treatment of metastatic HCC.     

褐藻糖胶抗血栓研究进展

褐藻糖胶是一种酸性硫酸化多糖，有多种生物活性和药理作用，其抗血栓活性尤为明显。褐藻糖胶能够抑制凝血酶的产生及活性，提高组织型纤溶酶原活化剂对纤溶酶原的激活作用，从而具有抗血栓形成和溶栓功能。     

Are murine marginal-zone macrophages the splenic white pulp analog of high endothelial venules?

The entry of lymphocytes into the spleen, in contrast to lymph nodes, does not involve high endothelial venule (HEV) interaction. The precise point of entry, as well as the mechanism by which lymphocytes enter the lymphoid areas of the spleen, remains controversial. We examined in detail the effect of two agents, pertussis toxin (PT) and the sulfated polysaccharide fucoidan, on splenic lymphocyte entry and positioning. These have previously been shown to interfere with lymphocyte extravasation across HEV. PT prevents lymphocyte extravasation, but not binding, to HEV, whereas fucoidan prevents binding and thus subsequent extravasation. Studies presented here show that pretreatment of murine lymphocytes with PT does not numerically affect entry into spleen, but profoundly alters lymphocyte positioning within the spleen. When fluorescently labeled, PT-treated lymphocytes are injected intravenously, they initially accumulate in the marginal zone, in apparent association with the layer of marginal zone macrophages (MZM?) which form a shell around the white pulp. They fail to traverse this layer into the white pulp, and subsequently localize in the red pulp. In contrast, untreated cells initially appear in the marginal zone, then continue to migrate into the white pulp after traversing the MZM? layer. The localization of PT-pretreated lymphocytes adjacent to the MZM? layer is disrupted by intravenous administration of fucoidan. Using a flow cytometric assay of aggregation between MZM? and lymphocytes, we confirmed that fucoidan is also able to inhibit this association in vitro, whereas PT has no effect on this interaction. We propose that MZM? in the mouse are the splenic analog of HEV, forming the port of entry of lymphocytes into the white pulp of the spleen.     

Genotoxicity studies on fucoidan from Sporophyll of Undaria pinnatifida

The sulfated seaweed extract, fucoidan, has anticoagulant, antithrombotic, and antiviral activities. Despite extensive work on the biological activities of fucoidan, detailed studies on the genotoxicity of fucoidan from Sporophyll of Undaria pinnatifida sources have not been tested before. The objective of this study was to investigate the genotoxicity effects of fucoidan extracted from Sporophyll of U. pinnatifida using a test battery of three different methods. In a reverse mutation assay using four Salmonella typhimurium strains and Escherichia coli, fucoidan did not increase the number of revertant colonies in any tester strain regardless of metabolic activation by S9 mix, and did not cause chromosomal aberration in short tests with S9 mix or in the continuous (24 h) test. A bone marrow micronucleus test in ICR mice dosed by oral gavage at doses up to 2000 mg/kg bw/day showed no significant or dose-dependent increases in the frequency of micronucleated polychromatic erythrocytes (MNPCE), and the high dose suppressed the ratio of polychromatic erythrocytes (PCE) to total erythrocytes. We conclude that fucoidan presents no significant genotoxic concern under the anticipated conditions of use.     

褐藻多糖硫酸酯对 TGF-β1体外诱导的肾小管上皮细胞间质转分化过程中细胞骨架的影响

目的：通过体外观察褐藻多糖硫酸酯对TGF-β1诱导肾小管上皮细胞（HK-2）间质转分化过程中细胞角蛋白（cytok-eratin,CK）和α-平滑肌肌动蛋白（α-smooth muscle action ,α-SMA）表达的影响,探讨该药对HK-2上皮-间质转分化的影响及其作用机制。方法体外培养正常人肾小管上皮细胞（ HK-2）细胞株,采用倒置相差显微镜观察对照组、诱导组和药物组细胞形态的变化,免疫细胞化学SABC法和图像分析技术检测培养第3 d对照组、诱导组和药物组HK-2细胞CK和α-SMA阳性细胞的平均光密度值。结果培养第3 d,对照组HK-2细胞呈现铺路石样上皮细胞形态特点,诱导组细胞呈长梭形,类似纤维细胞,药物组细胞以上皮细胞为主,少数细胞呈梭形;与对照组相比较,诱导组CK阳性细胞平均光密度值显著降低（ P＜0.05）,α-SMA阳性细胞平均光密度值增加（P＜0.05）;与诱导组相比较,药物组CK阳性细胞平均光密度值显著增加（P＜0.05）,α-SMA阳性细胞平均光密度值显著降低（P＜0.05）。结论①褐藻多糖硫酸酯具有抑制TGF-β1体外诱导的肾小管上皮细胞间质转分化的作用;②褐藻多糖硫酸酯可能通过改变细胞骨架成分发挥抑制肾小管上皮细胞间质转分化作用。