DNA damage response in resting and proliferating peripheral blood lymphocytes treated by camptothecin or X-ray

DNA damage response (DDR) in different cell cycle status of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated. The PBLs were stimulated into cell cycle with phytohemagglutinin (PHA). The apoptotic ratio and the phosphorylation H2AX (S139) were flow cytometrically measured in resting and proliferating PBLs after treatment with camptothecin (CPT) or X-ray. The expressions of γH2AX, Bcl-2, caspase-3 and caspase-9 were detected by Western blotting. DDR in 293T cells was detected after H2AX was silenced by RNAi method. Our results showed that DNA double strand breaks (DSBs) were both induced in quiescent and proliferating PBLs after CPT or X-ray treatment. The phosphorylation of H2AX and apoptosis were more sensitive in proliferating PBLs compared with quiescent lymphocytes (P<0.05). The expression levels of anti-apoptotic proteins Bcl-2 were reduced and cleaved caspase-3 and caspase-9 were increased. No significant changes were observed in CPT-induced apoptosis in 293T cells between H2AX knocking down group and controls. It was concluded that proliferating PBLs were more vulnerable to DNA damage compared to non-stimulated lymphocytes and had higher apoptosis rates. γH2AX may only serve as a marker of DNA damage but exert no effect on apoptosis regulation.     

传统疝修补术与Lichtenstein无张力疝修补术治疗腹股沟疝的对比研究

目的 探讨腹股沟疝修补的适宜手术方式.方法 240例腹股沟疝患者按照手术顺序编号分为传统疝修补术组(传统组)和Lichtenstein无张力疝修补术组(无张力组),每组120例.观察比较两组的临床指标和并发症.结果 传统组手术时间为(34.26±4.56) min,短于无张力组的(40.35±6.24) min,差异有统计学意义(P＜0.01);传统组进食、下床、住院时间分别为(6.73±0.64)h、(7.53±1.11)h、(8.53±3.06)d,均长于无张力组的(2.06±1.61)h、(2.63±0.83)h、(4.38±2.53)d,差异有统计学意义(P＜0.01);传统组住院费用为(4825.20±157.32)元,高于无张力组的(4683.47±151.28)元,差异有统计学意义(P＜0.01).两组恢复正常活动时间比较差异无统计学意义(P＞0.05).传统组恶心呕吐、头痛、尿潴留、切口疼痛(中度)发生率及复发率分别为5.83％(7/120)、5.00％(6/120)、19.17％(23/120)、32.50％(39/120)、10.83％(13/120),均高于无张力组的0、0、1.67％(2/120)、6.67％(8/120)、0.83％(1/120),差异有统计学意义(P＜ 0.05或＜0.01);两组切口感染、阴囊血肿、异物感、睾丸疼痛萎缩、慢性疼痛发生率比较差异无统计学意义(P＞0.05).结论 Lichtenstein无张力疝修补术与传统疝修补术相比能明显地减少患者术后近、远期并发症的发生率,恢复更快,是腹股沟疝修补的适宜手术方式.     

CDK1 siRNA干扰在Taxol诱导细胞凋亡中的作用

目的 研究转染细胞周期依赖性蛋白激酶1(cyclin-dependent kinase 1,CDK1)siRNA、以及转染后进行凋亡刺激对细胞周期和凋亡的影响,探讨CDK1在细胞凋亡中的确切作用,揭示细胞周期与细胞凋亡协调的分子机制.方法 以人宫颈癌细胞株HeLa细胞为研究对象,脂质体转染CDK1 siRNA,转染后48 h加紫杉醇(Taxol) (20 μg/ml)刺激凋亡,Western印迹检测CDK1和抗凋亡蛋白BCL2表达,AnnexinV/PI法检测细胞的凋亡,流式细胞仪分析DNA含量检测细胞周期.结果 转染CDK1 siRNA后,CDK1蛋白的表达下降,细胞周期G2/M期比例增加,细胞凋亡率与对照相比没有明显升高.只加Taxol刺激12 h后细胞凋亡率增加并伴有S期和G2/M期比例增加. 转染CDK1 siRNA后再用Taxol刺激,其细胞凋亡率没有明显改变,G2/M期阻滞效应也没有叠加.BCL2蛋白只在加Taxol刺激组表达下降,与CDK1表达减少没有相关性.结论 siRNA沉默导致的CDK1表达降低只导致细胞周期G2/M期阻滞,没有引起细胞凋亡;CDK1的表达降低对紫杉醇所诱导的细胞周期阻滞和细胞凋亡效应没有明显影响.     

生长激素对MOLT-4细胞增殖的影响

生长激素(GH)是由脑垂体前叶嗜酸性细胞所分泌的生长刺激因子[1].我们通过研究rhGH是否对人T淋巴细胞型白血病细胞株(Molt4)具有增殖作用以及观察生长激素受体(GHR)在Molt-4细胞中的表达,以期为rhGH的临床研究提供实验依据.     

X射线对人外周血淋巴细胞DNA损伤修复和凋亡的影响

目的 研究不同时间诱导X射线照射的淋巴细胞进入细胞周期DNA损伤修复与凋亡的影响.方法 X射线(0.5 Gy)作用于正常人外周血淋巴细胞,以照射后不同时间点(0、4 h)分别加入PHA并分成两组,即照射后0 h加PHA组(A组)和照射后4 h加PHA组(B组),再分别培养0、0.5、2 h,用流式细胞术和免疫印迹法检测A组和B组γ-H2AX蛋白的表达,Annexin-V/PI法分析A、B两组的细胞凋亡率.结果 流式细胞术及免疫印迹结果均显示A组的γ-H2AX蛋白表达高于B组(P＜0.05),且均先升高后降低.A组细胞凋亡率亦大于B组.结论 不同时间诱导被打击的淋巴细胞进入周期其可能发生DNA修复并同时伴随细胞凋亡的发生.