【作者】 李雪静；

【导师】 李娟；

【作者基本信息】 吉林大学 ， 劳动卫生与环境卫生学， 2006， 硕士

【摘要】 电离辐射是一种严重危害人体健康的有害因素,机体受到大剂量电离辐射会引起以骨髓造血功能障碍、胃肠道损伤或脑损伤为基本病变的急性放射病;长时间连续受到小剂量照射则会出现以造血组织损伤为主,伴有其它系统改变的全身性疾病;另外电离辐射对机体产生的损伤还具有远后效应和致癌效应。目前使用的众多辐射防护剂,大多为化学合成药物,但由于其在有效剂量上毒性较大,故实用价值有限,而天然植物以其毒副作用小、资源丰富,迅速成为辐射防护药物研究的新热点,其中多糖是近几年辐射防护药物研究的新亮点。本研究选用盛产于长白山区的真菌松茸,索式提取法去除脂类物质,水提醇沉法得到粗提物,三氯乙酸法去除蛋白得到本实验受试物-松茸多糖(Polysaccharide of Tricholoma Matsutake ,PTM)。本研究采用一次性全身X射线照射小鼠,建立辐射损伤模型,分别从免疫功能、抗氧化功能、造血功能等方面研究了PTM的辐射防护作用,并探讨其辐射防护作用机制。实验结果表明:PTM能够显著拮抗由于辐射损伤引起的体液免疫、细胞免疫和非特异性免疫功能下降,促进机体免疫功能恢复,缩短免疫功能恢复时间;增强辐射损伤小鼠SOD、GSH-Px和CAT抗氧化酶的活力,减少细胞受辐射引起的脂质过氧化反应,减轻自由基对机体的损伤,增强机体清除自由基的能力;保护造血干细胞、骨髓基质细胞,促进造血功能恢复,降低骨髓细胞DNA损伤,减轻细胞周期紊乱。提示:PTM可通过拮抗免疫损伤、清除自由基、降低造血损害三个作用发挥其辐射防护功能的。更多还原

【Abstract】 In 21^st century, the nuclear power station as representative’s peace usin-g the nuclear power will continously develop, the massive radioactivewaste in the nuclear power application will produce, interventional radiology and the radioactive isotope are generally applicated in the labor, agriculture and medicine, these all constitute to the ecology, the environment and the human health threat. Along with the human becoming an information based society process enhancement, the electro-magnetic radiationpollution will be everywhere. The radiation is a kind of serious harmfulfactor to human body health. Body receiving a large dose of radiationwill be able to cause acute radiation disease which leads to hematopoietic function barrier, the gastro-intestinal tract damage or the brain damageas the basic pathological changes. Receiving a long time radiation of small dose will appear the symptom of the hematopoietic system damagesprimarily, accompanied by other system disease;Moreover the damageof the radiation also has the far effect and the carcinogenic effect to body.At present,chemical drugs radioprotected mainly in clinical application have higher effects,but also higher adverse reaction and drug resistances.Consequently,it is urgent to find new drugs that have high performance and low toxicities. The natural plant posses distinct anti-radiation effects and low toxicities,become the hot spot of radiation protection medicine,Especially,Polysaccharide change to new lightspot in rencent reseach.Most study in recent years indicate that the natural active materialwhich possess antiradiation effects mainly is polysaccharide,generally existing in plants、eumycete and algae,a few glycoside、coumarins and alkaloid also have good effects. Polysaccharide of tricholoma matsutake（PTM） extracted from the natural eumycete--Tricholoma matsutake havemany biological activities,such as anticancer and immune enhancement.The purpse of this study is to investigate the protection of PTM againstdamages of immune system、anti-oxide system and hematogentic induced by radiation and the mechanism involved,and first report the experimental results that PTM exhisits radioprotection and get some experimentalevidences for application of PTM as an antiradiation agent.Methods Mice were exposed to total body radiation with a singledose of 2.0 Gy X-ray,the rate of dose is 0.287Gy·min-1 .We observed the effects of PTM on the damage of immunologic system and anti-oxidant system and hematopoietic system. Immunologic system including thymocytes and splenocy、the prolife reaction of splenocytes to ConA、the phagocytic ratio of mouse Mφ、the phagocytic index of mouse Mφ and antibody production response of splenocytes, anti-oxidant system including enzyme activities of SOD、GSH-Px and CAT and content of MDA, hematopoietic system including CFU-S、CFU-F、the level of DNA damage、cell cycle of bone marrow and micronucleus rates of bone marrow PCE were detected in 1st 、5th、14th day after radiation.Results （1） Immunological parameters included index of thymocytesand splenocy、the prolife reaction of splenocytes to ConA、the phagocytic ratio of mouse Mφ、the phagocytic index of mouse Mφ and antibodyproduction response of splenocytes showed a markedly increased in thegroups treated with PTM compared to a severe decrease in the IC groups. （2） The enzyme activities of superoxide dismutase （SOD）、glutathioneperoxidase （GSH-Px） and catalase （CAT） were significantly decreased when the mice were exposed to 2.0 Gy X-ray,while the content of malondialdehyde（MDA） was significantly increased at same dose of X-ray. PTMinduced a dose-dependant increase of enzyme activities of SOD、GSH-Px and CAT,and dose-dependant decrease of the content of MDA. The enzyme activities of SOD、GSH-Px and CAT in the high dose of PTM were same as NC group in 14th day after radiation. （3）PTM could preventmice from hematopietic suppression induced by radiation in a dose-dependant manner.PTM decreased the micronucleus rates of bone marrow PCE、the rate of comet cell and the length of comet、the percentage of G1phase of bone marrow cell;increased the colony forming units-spleen and fibrolast colony forming units.Conclusion In summary,our results indicate that pre-treatment of animals with PTM 7 days prior to X-ray exposure significantly inhibites X-ray induced damage in immunologic system and anti-oxidant system andhematopoietic system.Against immunologic injury、enhancing the abilityof cleaning free radical and decreasing hematopoietic system damage maybe one of the mechanisms that PTM protect mice against damage induced by radiation.However,further investigations are needed to interpret theother mechanisms.更多还原