ABSTRACT To study the protective effects of Sipunculus nudus polysaccharide (SNP) on human intestinal epithelial cell (HIEC) damage induced by ionizing radiation, the survival rate of HIECs was detected by CCK-8 method, and the concentration of SNP was identified. The effect of SNP on the proliferation ability of post-irradiated HIECs was analyzed by a cloning method. After 137Cs γ-ray irradiation for 48 h with the absorbed dose of 10 Gy, cell apoptosis was observed by microscopy using the Hoechst33342/PI staining, and the apoptosis rate and ROS levels were measured using flow cytometry. The results showed that the HIEC survival rate decreased significantly with the increasing absorbed doses. When HIECs were pretreated with a certain concentration of SNP, the survival rate increased significantly, showing a positive correlation with the concentration of SNP, and reached the maximum level when the SNP mass concentration was 50 μg/mL. After irradiation, the survival rate of the cloned cells was observed to be higher than that of irradiation model group. The apoptosis rate and intracellular ROS levels decreased significantly for HIECs pretreated with SNP as compared with the irradiation model group. These results indicated that the SNP pretreatment could protect HIECs from damage caused by radiation.The underlying mechanism might be attributed to free radical scavenging by SNP and reduction in cell apoptosis.

Objective To investigate the protective effect of sipunculusnudus polysaccharide (SNP) on HUVEC cell damage induced by ionizing radiation.Methods The survival rate of HUVEC cells was detected by CCK-8,after irradiation with 137Cs γ-rays and pre-treatment with SNP,and optimal absorption dose rate of 137Cs γ-ray was 8 Gy and optimal concentration of SNP was confirmed to be 100 g/mL.The radiation sensitivity of HUVEC cells pretreated with SNP was detected by clone formation assay.Apoptosis rate of HUVEC cells was measured by Hoechst33342/PI staining and flow cytometry.Results The results indicated that the survival rate of HUVEC cells decreased significantly with the increase of irradiation dose (P ＜ 0.01).When pretreated with SNP,the survival rate of HUVEC cells significantly increased,and it was positively correlated with the concentration of SNP.When the end concentration of SNP was as high as 100 μg/ml,the survival rate reached the highest (84.96％),and the survival rate after irradiation increased from 63.43％ to 84.96％ (P ＜0.01).The rate of clone formation in the SNP-treated group was also significantly higher as compared with that of the control group(P ＜ 0.01).Compared with the irradiation model group,the apoptosis rate and intracellular reactive oxygen species (ROS) levels in the SNP-treated group decreased significantly,with the apoptosis rate decreasing from 15.6％ to 6.8％,and ROS level decreasing from 47.10 × 104 to 41.77 × 104,with statistical signficance (P ＜ 0.05 or P ＜ 0.01).The blue fluorescence of the Hoechst 33342 coloring and red fluorescence of PI coloring also decreased signficantly in the SNP-treated group (P ＜ 0.01).Conclusion The results suggested that SNP pretreatment could increase cell survival rate and cloning rate after irradiation,reduce radiation-induced apoptosis and intracellular ROS levels effectively,indicating that SNP treatment could exert a certain protective effect on HUVEC cell damage induced by ionizing radiation.

目的 评价新型静电纺丝伤口敷料的止血性能及促创伤愈合作用,为该敷料的进一步开发应用奠定基础.方法 将胶原蛋白和壳聚糖的混合溶液通过静电纺丝技术纺织在海藻酸盐无纺布基布上,制备成新型静电纺丝伤口敷料(胶原蛋白-壳聚糖静电纺丝膜复合海藻酸盐敷料CCEAD).通过体外凝血实验、兔耳动脉创伤止血实验和兔背部创伤止血实验评价CCEAD的止血性能.建立大鼠背部全皮层创伤模型,分别在术后3、5、7、12 d拍照计算伤口愈合率,测定CCEAD的促愈合作用;取伤口创面皮肤组织,HE染色观察组织病理学变化;免疫组化染色观察在伤口愈合过程中CD31、FGF-2和TGF-β的表达情况.结果 CCEAD组的体外凝血指数BCI为36.91％±6.62％,显著小于阳性对照明胶海绵组(69.82％±1.83％)和阴性对照医用纱布组(79.93％±6.30％)(P＜0.01).兔耳动脉创伤止血实验中,CCEAD组的止血时间(107.67±17.62)s短于医用纱布组(163.67±15.50) s(P＜0.05).兔背部创伤止血实验中,CCEAD组Hb光度吸收值(0.120±0.052)明显低于医用纱布组(0.294±0.021) (P＜0.01).在促创伤愈合实验中,术后第7天,CCEAD组愈合率为65.70％±4.94％,高于阳性对照壳聚糖敷料组(48.78％±8.33％)(P＜0.05),明显高于医用纱布组(37.76％±6.35％)(P＜0.01).HE染色显示,CCEAD在伤口愈合早期能够促进成纤维细胞生长和新生血管形成,促进肉芽组织的生成.免疫组化结果显示,CCEAD能促进CD31、FGF-2和TGF-β在伤口愈合早期的表达,有利于伤口的愈合.结论 新型静电纺丝伤口敷料(胶原蛋白-壳聚糖静电纺丝膜复合海藻酸盐敷料)止血性能优良,具有明显的促创伤愈合作用,有望开发成新型伤口敷料.

探讨螯合剂(EDTA·Na2、DTPA、EDTMPA)和吸附剂(海藻酸钠和羧甲基壳聚糖)对Cs+污染伤口的洗消作用.通过皮肤打孔建立大鼠背部体表创伤模型,优化染毒液体积、洗消液体积、染毒时间等洗消实验条件,建立洗消实验模型.选取放射性核素铯的稳定同位素(Cs+)进行伤口染毒洗消实验,以3种螯合剂和2种吸附剂合适浓度的水溶液作为洗消液,采用一次性伤口脉冲冲洗系统对染毒伤口进行洗消,收集洗消液,用电感耦合等离子体发射光谱仪测定洗消液中Cs+含量,计算洗消效率.结果表明:螯合剂EDTA·Na2的洗消效率随着其浓度的增加而逐渐升高,浓度为0.6 mol/L的EDTA·Na2的洗消效率达到74.15％,显著高于生理盐水组(p<0.01).DTPA的洗消效率与生理盐水组比较没有显著差异.EDTMPA的洗消效率呈现先增加后减少的趋势,与生理盐水组比较,浓度为0.01 mol/L的EDTMPA的洗消效率显著增高(p<0.01),达到76.06％.吸附剂海藻酸钠的洗消效率随着其浓度的增加呈现升高趋势,与生理盐水组比较,3 g/L海藻酸钠的洗消效率显著增高(p<0.05),达到68.22％.羧甲基壳聚糖的洗消效率随着其浓度的增加呈现升高的趋势,与生理盐水组比较,4 g/L的羧甲基壳聚糖有显著性差异(p<0.01),达到74.22％.结果提示,螯合剂(EDTA·Na2、EDTMPA)和吸附剂(海藻酸钠、羧甲基壳聚糖)对Cs+具有良好的去污效果,有望开发成放射性核素Cs+污染伤口的高效洗消剂.