乳铁蛋白抗辐射损伤作用的基础研究

发布时间：2018-05-14 15:20

本文选题：乳铁蛋白 + 辐射损伤　；参考：《济南大学》2013年硕士论文

【摘要】：目的：随着核技术的迅速发展，电离辐射的应用已经发展到各个领域。工业、科研和医学等领域使用的X射线探伤机、放射性同位素、X射线机、直线加速器等，一旦造成事故就会给人体造成不同程度的损伤。人体的多个系统如造血系统、免疫系统和生殖系统对电离辐射非常敏感。因此，人体长期或者大剂量接受电离辐射，会引起细胞、组织和器官损伤，诱发各种疾病，，诱发癌症、白血病，甚至引起死亡。乳铁蛋白是一种非血红素铁结合性糖蛋白，广泛分布于哺乳动物的乳汁、唾液、泪液等分泌物和血液、嗜中性粒细胞中。乳铁蛋白已在多个领域表现出特有的生物活性，如促进肠道铁吸收、抑菌与杀菌、抗氧化作用、免疫调节作用、促进肠道内双歧杆菌生长功能、抗感染作用、抗癌作用、药物协同作用。2006年，日本研究人员通过动物实验证实，乳铁蛋白具有防止辐射损伤的功效，并认为这种作用与乳铁蛋白的抗氧化作用有关。本课题通过研究乳铁蛋白对辐射损伤小鼠抗氧化、免疫功能、细胞凋亡等的影响，进一步探讨乳铁蛋白对小鼠的抗辐射损伤作用及可能存在的机制，为研究新型放射防护剂提供新的思路和方法。方法：首先研究乳铁蛋白对小鼠辐射损伤的防护作用。36只SPF级Balb/c小鼠适应性饲养1周，观察无异常后参照随机区组法分组，随机分为正常对照组、照射对照组和hLF组，每组12只，照射对照组和hLF组给予2Gy X射线全身照射。照射后hLF组每只小鼠腹腔注射4.0mg/ml的乳铁蛋白溶液1.0ml；正常对照组和照射对照组腹腔注射0.9％氯化钠注射液各1.0ml，各组小鼠自由饮食。照射后24h，处死小鼠取材，检测免疫器官指数、T淋巴细胞亚群比例、血清SOD活力、MDA水平、外周血象。另取Balb/c小鼠30只，分组、照射、给药及饮食方式同上述实验。给药20h后，每组小鼠腹腔注射体积分数为5％鸡红细胞悬液1.0ml，4h后，取材，检测腹腔巨噬细胞吞噬功能。第二是研究乳铁蛋白对脾细胞凋亡和细胞因子的影响。取Balb/c小鼠30只，分组同上述实验。hLF组按50mg/kg hLF灌胃给药，1次/d，连续7d；正常对照组和照射对照组灌胃0.9％氯化钠注射液，20ml/kg，1次/d，共7d。末次给药后2h，照射对照组和hLF组给予2Gy X射线全身照射，各组小鼠自由饮食。照射后24h，处死小鼠取材，检测脾细胞凋亡、血清Bcl-2、IL-1β、IL-2。结果：乳铁蛋白对小鼠辐射损伤的防护作用实验。实验结果发现，照射后，照射对照组和hLF组小鼠与正常对照组比较，小鼠胸腺和脾脏指数、CD8+淋巴细胞比例、SOD活力、WBC、LYM％、腹腔巨噬细胞吞噬指数和吞噬百分率均显著降低（P0.01），而MDA水平、CD4+淋巴细胞比例均显著增高，差异有统计学意义（P0.01）；hLF组小鼠脾脏和胸腺指数、CD4+、CD8+淋巴细胞比例、SOD活力、LYM％、腹腔巨噬细胞吞噬指数和吞噬百分率明显高于照射对照组（P0.01，P0.05），而MDA水平显著低于照射对照组，差异有统计学意义（P0.01）。乳铁蛋白对脾细胞凋亡和细胞因子的影响实验。实验结果发现，照射后，小鼠脾细胞凋亡增多，照射对照组小鼠脾细胞凋亡的细胞比例（包括早期凋亡细胞和晚期凋亡细胞）显著高于正常对照组，差异具有统计学意义（P0.05）；hLF组小鼠脾细胞凋亡细胞的比例正常对照组有所升高，差异无统计学意义（P0.05）；hLF组小鼠脾细胞凋亡细胞的比例显著低于照射对照组，差异有统计学意义（P0.01）。hLF组小鼠血清Bcl-2、IL-1β、IL-2浓度显著高于照射对照组，差异有统计学意义(P0.05)。结论： 1.免疫器官指数计算结果提示乳铁蛋白可能能够防止电离辐射引起的胸腺和脾脏的过度损伤并促进其恢复。 2.脾脏T淋巴细胞亚群和腹腔巨噬细胞吞噬实验证实乳铁蛋白对电离辐射引起的免疫功能损伤具有保护作用。 3.抗氧化实验的结果提示乳铁蛋白可提高电离辐射损伤后小鼠机体内清除自由基的能力和抗氧化能力。 4.乳铁蛋白提高辐射损伤小鼠外周血LYM％，但是对WBC、RBC、PLT等无明显的保护作用，这还需要进一步的研究。 5.脾淋巴细胞凋亡和血清Bcl-2测定结果表明乳铁蛋白可能通过提高bcl-2的表达，发挥抑制细胞凋亡的作用。 6.IL-1β、IL-2测定结果表明乳铁蛋白能够增强IL-1β、IL-2的分泌来抑制辐射后机体的免疫功能的损伤。
[Abstract]:Purpose :

With the rapid development of nuclear technology , the application of ionizing radiation has been developed into various fields , such as X - ray detectors , radioactive isotopes , X - ray machines and linear accelerators used in the fields of industrial , scientific research and medicine .

Method :

The protective effects of lactoferrin on radiation injury in mice were studied . Thirty - six SPF - grade Balb / c mice were randomly divided into two groups : normal control group , control group and hLF group .
In the normal control group and the control group , 0.9 % sodium chloride injection was injected intraperitoneally with 1.0 ml each group . The mice were sacrificed 24 hours after irradiation . The mice were sacrificed for 24 h , the proportion of T lymphocyte subsets , serum SOD activity , MDA level and peripheral blood image were detected .

The second was to study the effect of lactoferrin on apoptosis and cytokines in spleen cells . Balb / c mice were divided into 30 groups and group with the above - mentioned experiment . hLF group was given orally at 50mg / kg hLF , and lasted for 7 days .
In the normal control group and the control group , 0.9 % sodium chloride injection , 20 ml / kg , 1 time / day were injected into the control group for 7 days . 2 hours after the last dose , 2 Gy X - ray whole body irradiation was given to the control group and the hLF group . After irradiation , the mice were irradiated for 24 hours , the mice were sacrificed and the apoptosis of the spleen cells , the serum Bcl - 2 , IL - 1尾 and IL - 2 were detected .

Results :

The protective effects of lactoferrin on radiation injury in mice were observed . The results showed that the percentage of thymus and spleen index , percentage of CD8 + lymphocytes , SOD activity , WBC , LYM % , phagocytic index and phagocytic percentage of peritoneal macrophages decreased significantly after irradiation ( P0.01 ) , while the levels of MDA and CD4 + lymphocytes increased significantly ( P0.01 ) .
In hLF group , spleen and thymus index , CD4 + , CD8 + lymphocyte ratio , SOD activity , LYM % , phagocytic index and phagocytic percentage of peritoneal macrophages were significantly higher than those in control group ( P0.01 , P0.05 ) , while MDA level was significantly lower than that in control group ( P0.01 ) .

The effects of lactoferrin on apoptosis and cytokines in spleen cells showed that the apoptosis of spleen cells increased after irradiation , and the percentage of apoptosis in spleen cells ( including early apoptotic cells and late apoptotic cells ) was significantly higher in the irradiated mice than in the normal control group ( P0.05 ) .
The percentage of apoptotic cells in spleen cells of hLF group was higher than that of control group ( P0.05 ) .
The percentage of apoptotic cells in spleen cells of hLF group was significantly lower than that in control group ( P0.01 ) . The levels of Bcl - 2 , IL - 1尾 and IL - 2 in serum of hLF group were significantly higher than those in control group ( P0.05 ) .

Conclusion :

1 . The results of the immune organ index suggest that lactoferrin may be capable of preventing excessive damage of thymus and spleen caused by ionizing radiation and promoting its recovery .

2 . The spleen T lymphocyte subsets and the phagocytosis of peritoneal macrophages confirmed that lactoferrin had a protective effect on the immune function injury induced by ionizing radiation .

3 . The results of anti - oxidation experiments suggested that lactoferrin could enhance the ability of scavenging free radicals and anti - oxidation ability in mice after ionizing radiation injury .

4 . Milk ferritin increased lyM % in peripheral blood of irradiated mice , but there was no obvious protective effect on WBC , RBC , PLT .

5 . Apoptosis of splenic lymphocytes and the determination of Bcl - 2 in serum showed that lactoferrin could play a role in inhibiting apoptosis by increasing the expression of bcl - 2 .

6 . IL - 1尾 , IL - 2 assay showed that lactoferrin could enhance the secretion of IL - 1尾 and IL - 2 to inhibit the immune function of IL - 1尾 and IL - 2 .

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R142

【参考文献】