造血干细胞移植辐射预处理生物标志物的实验研究

Study of biological markers for radiation pretreatment of hematopoietic stem cell transplant recipients

目的研究小鼠受^60C0γ射线照射后血液和免疫系统的早期生物参数变化，为造血干细胞移植（HSCT）受者放疗预处理寻找灵敏可靠的生物剂量标志物。方法采用纯品系BALB／c雄性小鼠，随机分为1个对照组和3个照射组。应用^60C0γ射线全身照射，吸收剂量分别为0、2、4和6Gy。照射后24h，外周血白细胞计数及淋巴细胞百分率应用血常规计数测定；外周血和骨髓嗜多染红细胞微核（inn—PCE）应用Giemsa染色镜下计数观察；骨髓细胞、脾脏和胸腺早期凋亡率应用Annexin V／PI双染法流式细胞仪检测。结果与对照组比较，各照射组小鼠外周血白细胞计数及淋巴细胞百分率随辐射剂量增加而显著降低（P〈0．01），其回归方程分别为E=0．1750D^2-1．7440D＋5．2020和E=84．9390-3．4255D；外周血和骨髓mn．PCE随辐射剂量增加而显著增加（P〈0．01），骨髓mn—PCE与辐射剂量呈正相关，其回归方程为E=3．9725D＋2．9700；骨髓细胞、脾脏和胸腺早期凋亡率随辐射剂量增加而显著增高（P〈0．01），呈线性正相关，回归方程分别为E=3．42D＋8．36，E=3．0645D＋3．1840和E=2．5620D＋2．5090。结论外周血淋巴细胞计数和骨髓嗜多染红细胞微核率与辐射剂量呈线性相关，其回归方程可作为放射预处理剂量评估灵敏可靠的早期生物剂量标志物；骨髓细胞、脾脏和胸腺淋巴细胞早期凋亡率与辐射剂量呈线性正相关，其回归方程可用于HCST受者放射预处理免疫系统抑制程度的判定指标。

Objective To study the early biological parameterchanges of blood and immune systems of mice after ^60C0 γ-ray irradiation in order to find sensitive and reliable biological dose markers for radiation pretreatment ofhematopoietic stem cell transplant recipients. Methods Pure strain BALB/c male mice were randomly divided into control group and three irradiation groups and absorbed doses of total body irradiation by ^60C0 γ-ray were 0, 2, 4, 6 Gy, respectively. In 24h after irradiation, WBC counts and lymphocyte percentages of peripheral blood were determined by blood cell counting; polychromatic erythrocyte micronucleus （mn- PCE） of peripheral blood and bone marrow were observed by microscope after Giemsa staining; apoptosis rates of bone marrow, spleen, thymus cells were assayed by flow cytometry using Annexin V and PI double staining. Results Compared with the control group, WBC counts and lymphocyte percentages of peripheral blood in the irradiated groups significantly decreased with the increase of radiation doses （P〈0.01）, and their regression equations were E=O.1750D^2- 1.7440D＋5.2020 and E=84.9390-3.4255D respectively. The mn-PCE of peripheral blood and bone marrow in the irradiated groups significantly increased with the increase of radiation doses （P〈0.01）, bone marrow mn-PCE was positively correlated with the radiation dose with regression equation as E=3.9725D＋2.9700. The early apoptosis rates of bone marrow cells, spleen and thymus cells significantly increased with the increase of radiation doses （P〈0.01）, which were positively correlated with radiation doses, and their regression equations were E=3.42D ＋ 8.36, E=3.0645D ＋ 3.1840 and E=2.5620D ＋ 2.5090 respectively. Conclusions Peripheral blood lymphocyte count and bone marrow mn-PCE rate were linearly correlated to radiation doses, which could be used as sensitive and reliable early biological markers of the radiation pretreatment recipients, and the doses of the radiation pretreatment recipients could be accurately judged according to their regression equations. The early apoptosis rates of bone marrow, spleen and thymus cells were positive linear correlation with the radiation doses, and their regression equations could be used to judge the degree of inhibition of the immune system for radiation pretreatment recipients.