Cytotoxicity of the β-carboline alkaloids harmine and harmaline in human cell assays in vitro

beta-Carboline alkaloids are natural products widely distributed in plants and also found in alcoholic beverages, well-cooked foods and tobacco smoke. Various authors have reported genotoxic activities of several carboline in prokaryotic and eukaryotic cells that have been attributed to their abilities to intercalate into DNA. But studies on the genotoxic and on the cytotoxic potencies in human cells in vitro are not found in the literature. In the present study the toxicities of one full aromatic beta-carboline alkaloid (harmine) and one dihydro-beta-carboline alkaloid (harmaline) were evaluated by means of two in vitro human cell assays: the cytochalasin-B blocked micronucleus (CBMN) assay and the viability/colony formation assay with four different human cultured non-transformed (CCD18Lu) and transformed (HeLa, C33A and SW480) cells. Neither alkaloid was able to induce micronuclei levels above that of control levels in a wide range of doses tested; although, harmine at the highest concentrations assayed induced apoptotic as well as necrotic cells. Harmine produced a good viability of all cell lines assayed (control and tumor) while harmaline significantly reduced the viability of transformed and non-transformed cell lines in a dose-dependent manner. Harmine displayed a dose-dependent inhibitory effect on cell proliferation against all human carcinoma cells, but the SW480 transformed cell line showed a higher sensitivity. These results suggested that harmine was identified as a useful inhibitor of tumor development.     

培养人淋巴细胞分裂阻滞与常规微核测试法的比较研究Ⅲ．微核直径和微核率的检测比较

采用未照射（对照）和体外放射线照射３个供血员的全血，检测应用细胞松弛素法（ＣＢ）与常规法，对测得的淋巴细胞微核直径和微核率作了比较。结果表明：１）３．１Ｇｙ的γ－线照射，ＣＢ法微核率７．５１７％高于常规法６．１７１％（Ｐ＜０．０５）；ＣＢ法平均微核体积是常规法的１．８倍，ＤＮＡ损伤检测效率是常规法的２．２倍。２）未照射组中，ＣＢ法测的健康人自发微核率０．７６７％也高于常规法０．４９２％（Ｐ＜０．０５）；ＣＢ法平均微核体积是常规法的１．６倍，ＤＮＡ损伤检测效率是常规法的２．５倍。结合文献资料可认为，ＣＢ法在检测电离辐射的诱变性上较常规法敏感。细胞松弛素Ｂ有一定的遗传毒性，实际工作中应有选择地使用ＣＢ法。     

优化胞质分裂阻滞实验方案用于核质桥分析的可行性

目的探索优化胞质分裂阻滞实验方案用于辐射诱导核质桥分析的可行性,为以核质桥为指标进行生物剂量估算提供科学依据。方法用2 Gy ⁶⁰Coγ射线(剂量率为1 Gy/min)照射人离体外周血(设0 Gy对照),照射后28 h在细胞样品中加入终浓度为6μg/ml的松胞素B,培养48、56、68和72 h后收获;或照射后加入终浓度为0.6、1、2、6、10μg/ml的松胞素B,培养68 h后收获。应用胞质分裂阻滞法进行标本制备,分析单核细胞、双核细胞、多核细胞的比例,以及辐射诱导核质桥率及微核率。结果对不同细胞培养时间,随细胞培养时间的增加,0和2 Gy核分裂指数和双核细胞比例具有升高的趋势;2 Gy核质桥率无明显变化规律(0.0230~0.0330/细胞),差异无统计学意义(P>0.05),微核率差异亦无统计学意义(P>0.05)。对不同浓度松胞素B处理组,随松胞素B浓度的增加,0和2 Gy时核分裂指数和双核细胞比例有所升高;2 Gy核质桥率无明显变化规律(0.0230~0.0470/细胞),差异无统计学意义(P>0.05);与6μg/ml组相比,10μg/ml组微核率显著降低(U=2.74,P<0.01)。结论不同细胞培养时间组和不同松胞素B浓度组的辐射诱导核质桥率差异无统计学意义。适当缩短细胞培养时间可提前得到核质桥分析结果;培养开始加入松胞素B可简化实验步骤,但可供分析的细胞数过少,用于剂量估算的可行性尚需进一步研究。