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Objective:With the rapid development of nuclear technology, the application of ionizingradiation has developed into various areas. In the industry, scientific research andmedicine, once the X-ray detection apparatus, radioactive isotope, X ray machine,linear accelerator cause accidents, it would cause varying degrees of damage toperson. There are many systems of person such as hematopoietic system, immunesystem and reproductive system is sensitive to ionizing radiation. Therefore, if humanaccept long-term or large dose ionizing radiation, the cell, tissue and organ would bedamaged, and various diseases, cancer, leukemia and so on also would be bring outand even cause death. Lactoferrin is one of nonheme iron-binding glycoproteins.Lactoferrin is widely distributed in the milk of mammalian, saliva, tears, and othersecretions, in addition, lactoferrin is also found in the blood and neutrophils.Lactoferrin has unique biological activity in different realms, such as the promotion ofintestinal iron absorption, bacteriostatic effect and bactericidal effect anti-oxidation,immunomodulation effect, the promote function of intestinal bifidobacteria growth,anti-infection effect, anti-cancer effects, drug synergism and so on. In2006, Japaneseresearchers confirmed that lactoferrin has protective effect on acute radiation injurythrough the animal experiments, meanwhile they pointed that the effect of lactoferrinwas closely related with the anti-oxidant of lactoferrin. The effect of lactoferrin onanti-oxidant, immunoprotection and apoptosis and so on to radiation in mice wasstudied to further analysis the effect of lactoferrin against radiation in mice and themechanism in mice. And it could provide new ideas and methods to the study of newradiation protective medicament.Methods：First, the effects of lactoferrin against injuries induced by radiation was studied.36SPF Balb/c male mice that were fed for1weeks and had no abnormality wererandomly divided into3groups as a normal control group, an irradiated group and ahLF group, with12rats in each group. The control group and the hLF group weregiven2Gy X-rays.2hours later, the mice in hLF group received intraperitoneal injection of1.0ml4.0mg/ml lactoferrin solution. And the mice in the normal controlgroup and the irradiation group received1.0ml saline.24hours after irradiation, themice were sacrificed to detect immune organ index, T lymphocyte subsets, activitiesof SOD, MDA, the peripheral hemogram. Another30Balb/c mice, the method ofgrouping, irradiation, administer medication and diet was the same with the aboveexperiment.20hours after administered, each group of mice were injected5%volumefraction of chicken red blood cell suspension1.0ml by intraperitoneal, and4hourslater, the mice were sacrificed to detect the phagocytic function of peritonealmacrophage.Second, the effects of lactoferrin on apoptosis and cytokine spleen cells wasstudied.30Balb/c mice, the method of grouping was the same with the aboveexperiment. The mice in hLF Group received50mg/kg of hLF by administration,1time/d, continuous7d, and the mice in normal control group and irradiation groupwere administered with saline,20ml/kg,1time/d, continuous7d.2h after the lastadministration, the irradiated control group and hLF group were given2Gy X-rays.24h after irradiation, the mice were sacrificed to detect the apoptosis of spleen cellsand the concentration of Bcl-2, IL-1β and IL-2in serum.Results：Experiment research in the effects of lactoferrin against Injuries Induced byRadiation. The result of this experiment was that the index of thymus and spleen, thepercentage of CD8+lymphocytes in mice, SOD activity, WBC, LYM%, thephagocytic index and phagocytic percentage of peritoneal macrophage in irradiationcontrol group and hLF group were significantly decreased compared with those of thenormal control group(P<0.01), while the level of MDA, CD4+lymphocyte percentageincreased significantly, the difference between both groups was statistically significant(P<0.01); in the hLF group, the spleen and thymus index, CD4+and CD8+lymphocyte percentage, SOD activity, LYM%and the peritoneal macrophagephagocytic index and phagocytic percentage were all higher than that of the irradiatedcontrol group, while the level of MDA was significantly lower than the irradiatedcontrol group, the different between both groups was statistically significant (P<0.01,P<0.05).The effects of lactoferrin on apoptosis and cytokine spleen cells was studied. Theresult of this experiment was that the ratio of apoptosis in mouse spleen cells(including the apoptotic cells in early and late apoptotic cells) was significantly higher than that in normal control group, the difference between irradiated control group andhLF group was statistically significant (P<0.05); result there was group no significantdifference in the percentage of apoptotic cell of hLF group and normal controlgroup(P>0.05); result of apoptotic cell percentage in hLF group was significantlylower than that of the irradiated group, the difference between both groups wasstatistically significant (P<0.01). Experimental results show that the serum Bcl-2, IL-1β, IL-2concentration of hLF group was significantly higher than that of the irradiatedgroup, the difference between both groups was statistically significant (P<0.05).Conclusion：1.The calculation results of Immune organ index suggest may be able to preventthe thymus and spleen of excessive damage caused by ionizing radiation andpromote its recovery.2.The experiment of spleen T lymphocyte subgroup and abdominal macrophagephagocytosis approves that Lactoferrin has a protective effect on immune functiondamage caused by ionizing radiation3.The results of Antioxidant experiment suggest lactoferrin can increase the abilityof scavenging free radicals and antioxidant capacity of the mice which was injuryedby the ionizing radiation4.Lactoferrin could increase the peripheral blood LYM%of mice that wasinjuryed by ionizing radiation, but for the WBC, RBC, PLT, there was no significantprotective effect, which needs further research.5.The determination results of Spleen lymphocytes apoptosis and serum Bcl-2show that lactoferrin can increase the expression of Bcl-2, and play the role ofinhibition of apoptosis.6. the determination results of IL-1βand IL-2show that lactoferrin can enhancethe secretion of IL-1beta, IL-2to suppress the injury of body’s immune functionafter ionizing radiation
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