目的 探讨白药子总生物碱对 X 射线辐射损伤致小鼠白细胞减少的保护作用及其机制。方法 采用辐射法（一次性全身照射，照射剂量 2.5 Gy）制备白细胞减少症小鼠模型，90 只昆明种小鼠随机分为对照组，模型组，白药子生物碱低、中、高剂量（1.25、2.50、5.00 mg·kg^-1）组以及重组人粒细胞刺激因子（G-CSF）阳性对照组，共 6 组，每组 15 只。除对照组外，各组小鼠均进行 1 次性全身照射，白药子总生物碱各组分别于照射前 3 d 及照射后连续 ig 给药 3、15 d，G-CSF 组于照射前 3 d sc 给药，照射后 ig 给药 15 d。实验结束后取小鼠股骨计算有核细胞数及 DNA 水平。处死小鼠后称取小鼠肝脏、脾脏和胸腺质量，计算脏器指数。采用血液学分析仪分别于照射前及照射后 3、7、15 d 对外周血细胞中的白细胞（WBC）进行计数。收集小鼠血清，采用酶联免疫吸附法检测粒细胞-巨噬细胞集落刺激因子（GM-CSF）、血清 γ 干扰素（IFN-γ）、白细胞介素-3（IL-3）、白细胞介素-4（IL-4）、血管细胞黏附分子-1（VCAM-1）和可溶性细胞间黏附分子（SICAM-1）。通过苏木精和伊红染色检测小鼠肝脏、脾脏的病理变化。电镜观察脾脏、肝脏的超微结构。取肝脏组织，检测抗氧化相关指标。结果 白药子总生物碱可以明显抑制 X 射线照射后 14 d 内外周血白细胞的减少，同时提高 X 射线辐射后的骨髓 DNA 水平及小鼠造血生长因子 GM-CSF 水平，提高 X 射线辐射后免疫炎症因子 IL-3、SICAM-1 水平，减轻肝脏和脾脏组织损伤，维持小鼠肝脏、脾脏正常功能，并显著降低肝脏中的丙二醛（MDA）和黄嘌呤氧化酶（XOD）水平。结论 白药子总生物碱增强免疫和造血功能，揭示其作为放射防护剂和辐射缓解剂的治疗潜力。

Objective To investigate the protective effect and the mechanism of the total alkaloids of Stephaniae Cepharantha Radix on leukopenia induced by X-ray radiation damage in mice. Methods A mouse model of leukopenia was made by radiation method (one-time whole-body irradiation, irradiation dose of 2.5 Gy). Kunming mice were randomly devided into six groups: control group, model group, total alkaloids of Stephaniae Cepharantha Radix low, medium, high dose (1.25, 2.50, 5.00 mg·kg^-1) groups, and granulocyte colony-stimulating factor (G-CSF) positive control group with 15 animals in each group. Except for the control group, all groups of mice were subjected to one-time whole-body irradiation, and the total alkaloids of Stephaniae Cepharantha Radix were ig administered consecutively for 15 d before and after irradiation in each group, respectively, while the G-CSF group was sc administered for 3 d before irradiation and ig for 15 d after irradiation. The number of nucleated cells and DNA level were calculated after the experiment. Liver, spleen and thymus mass were weighed to calculate organ indices after execution of mice. White blood cells (WBC) in peripheral blood cells were counted before and 3, 7 15 d after, respectively, by using a hematology analyzer. Serum from mice were collected by enzyme-linked ELISA for granulocyte-macrophage colony-stimulating factor (GM-CSF), serum interferon (IFN-γ), interleukin-3 (IL-3), interleukin-4 (IL-4), vascular cell adhesion molecule 1 (VCAM-1) and soluble intercellular adhesion factor (SICAM-1). Pathologic changes in the liver and spleen of mice were detected by hematoxylin and eosin staining. The ultrastructure of spleen and liver was observed by electron microscopy. Liver tissue was obtained and tested for antioxidantrelated indices. Result It showed that the total alkaloids of Stephaniae Cepharantha Radix could significantly inhibit the reduction of peripheral blood leukocytes within 14 d after X-ray irradiation, at the same time increase the content of bone marrow DNA and the content of hematopoietic growth factor GM-CSF in mice after X-ray radiation, increase the content of immunoinflammatory factors IL-3 and SICAM-1 after X radiation, reduce the damage of liver and spleen tissues, maintain the normal function of the liver and spleen in mice, and significantly reduce the levels of malondialdehyde (MDA) and xanthine oxidase (XOD) in liver. Conclusion Enhancement of immune and hematopoietic functions by the total alkaloids of Stephaniae Cepharantha Radix reveals its therapeutic potential as a radioprotective and radiation mitigating agent.

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