rhIL-12对恒河猴造血系统辐射防护作用的初步研究

摘要本研究旨在初步观察重组人白介素-12（rhIL-12）对急性辐射损伤猴造血系统的防护和治疗作用，为同类型病人的临床救治提供实验依据。在体外实验中，观察了不同浓度rhIL-12（0、1、5、25、125和625ng/ml）对来自人和健康成年猴骨髓造血祖细胞集落形成能力的影响。在体内实验中，用11只经3．0Gy全身照射后90d活存猴再经致死剂量^60Coγ（6．0Gy）射线全身1次照射以建立重度骨髓型急性放射病动物模型。模型动物被随机分为照射对照组（n=4）、单次给药组（n=3）和分次给药组（n=4）。单次给药组于照射后2h皮下注射rhIL-124μg／kg，分次给药组分别于照射后2h和3、6、9d皮下注射rhIL-121μg/kg，对照组于皮下注射同样体积的PBS。观察照射后动物活存情况和外周血象变化。体外培养结果显示，不同浓度rhIL-12可明显促进正常猴和人骨髓单个核细胞形成各系造血祖细胞集落，特别是CFU-E和CFU-GM最为明显。照射对照组动物于照射后22d内全部死亡，死亡动物平均活存时间为（20．3±1．2）d；rhIL-12单次给药组3只动物全部存活，rhIL-12分次给药组1只动物于照射后17d因贫血死亡。与对照组比较，rhIL-12治疗能明显提高动物存活（P=0．018），并促进外周血白细胞数、血红蛋白水平、血小板以及网织红细胞数的恢复（P〈0．05）。结论：rhIL-12可明显促进灵长类骨髓造血祖细胞体外集落形成，并明显促进重度骨髓型急性放射病猴的造血功能恢复，提高动物存活率。

Radiation Protection Effect of rhIL-12 on Monkey Hematopoietic System

This study was aimed to investigate the radioprotective effects of recombinant human interleukin-12 （ rhlL- 12 ） on monkey hematopoietic system, and to provide experimental evidence for future clinical prophylaxis and treatment for patients who suffered from acute radiation syndrome. In in vitro study, the effect of rhIL-12 in different concentrations （0,1,5, 25,125 and 625 ng/ml） on colony forming capacity of human or monkey bone marrow-derived mononuclear cells was examined in methylcellulose H4434 medium. In in vivo study, the acute radiation syndrome model was established in 11 Rhesus monkeys which received lethal total body irradiation by 6 Gy ^60Coγin single time irradiation. The irradiated monkeys were randomly divided into 3 subgroups： control group （n = 4） which received subcutaneous PBS injection, rhIL-12 single-close group （n = 3） which received subcutaneous single injection of rhIL-12 （4 μg/kg） at 2 h after irradiation, and multiple-dose group （n = 4） which received subcutaneous injection of rhIL-12 （1 μg/kg per injection） at 2 h, day 3, 6 and 9 after irradiation respectively. Peripheral blood cells were counted before and after irradiation every other day. The survival status of animals were observed daily. In vitro test results showed that different concentrations of rhIL-12 obviously promoted human and healthy monkeys＇ bone marrow mononuclear cells to form various hematopoietic progenitor cell colonies, especial CFU-E and CFU-GM. All animals in control group died within 22 d after lethal tota/body irradiation, average survival time was （20.3 ± 1.2） d. Only one monkey in multiple-dose group died due to anemia on day 17. All monkeys in single-dose group survived. Compared with control group, rhIL-12- administrated monkeys＇ white blood cell count, hemoglobin level, platelet and reticulocyte counts showed faster recovery from high dose radiation. It is concluded that the rhlL-12 treatment can promote the bone marrow hematopoietic stem/ progenitor cell colony formation in vitro and protect lethally-irradiated monkeys. There is an obvious therapeutic effect of rhIL-12 on monkeys suffered from bone marrow failure caused by severe acute radiation exposure.