Study On The Effects Of PTM In Irradiated Mice And The Mechanism Of PTM's Radiprotection

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.