Effect of lonizing Radiation on the Expression of p16,CyclinD1 and CDK4 in Mouse Thymocytes and Splenocytes

OBJECTIVE: To investigate the effect of ionizing radiation on the expression of p16, CyclinD1, and CDK4 in mouse thymocytes and splenocytes. METHODS: Fluorescent staining and flow cytometry analysis were employed for the measurement of protein expression. RESULTS: In time course experiments, it was found that the expression of p16 protein was significantly increased at 8, 24, and 48 h for thymocytes (P < 0.05, P < 0.01, and P < 0.05, respectively) and at 24 h for splenocytes (P < 0.05) after whole body irradiation (WBI) with 2.0 Gy X-rays. However, the expression of CDK4 protein was significantly decreased from 8 h to 24 h for thymocytes (P < 0.05-P < 0.01) and from 8 h to 72 h for splenocytes (P < 0.05-P < 0.01). In dose effect experiments, it was found that the expression of p16 protein in thymocytes and splenocytes was significantly increased at 24 h after WBI with 1.0, 2.0, and 4.0 Gy (P < 0.05-P < 0.01), whereas the expression of CDK4 protein was significantly decreased with 2.0 Gy for thymocytes (P < 0.05) and 0.5-6.0 Gy for splenocytes (P < 0.05-P < 0.01). Results also showed that the expression of CyclinD1 protein decreased markedly in both thymocytes and splenocytes after exposure. CONCLUSION: The results indicate that the expression of p16 protein in thymocytes and splenocytes can be induced by ionizing radiation, and the p16-CyclinD1/CDK4 pathway may play an important role for G1 arrest of thymocytes induced by X-rays.     

X射线对小鼠脾细胞内P16、cyclin D1和CDK4表达的影响

目的:探讨X射线对小鼠脾细胞内P16、cyclin D1和CDK4表达的影响.方法:采用细胞间接荧光标记法、FACScan流式细胞仪检测不同剂量X射线全身照射后小鼠脾细胞内P16、cyclin D1和CDK4三种蛋白表达的时程变化和量效关系.结果:2.0 Gy X射线照后24 h小鼠脾细胞P16表达明显高于假照组;CDK4表达水平在照后8 h明显降低,持续至照后72 h仍低于正常水平.周期蛋白cyclin D1表达轻度下调.不同剂量照射后P16蛋白表达呈剂量依赖性增加,1.0～4.0 Gy组与假照射组相比显著增多(P＜0.05,P＜0.01);cyclin D1蛋白表达随剂量升高有降低趋势;CDK4亦呈剂量依赖性降低,0.5～6.0 Gy组与假照组比较差异具有显著性(P＜0.05,P＜0.01).结论:P16/cyclin D1/CDK4/pRb通路在电离辐射诱导脾细胞G1期阻滞中可能起十分重要作用.     

G1 Arrest and Relative Protein Expressions in Mouse Thymocytes Induced by Whole Body X—Ray Irradiation

Objective:To investigate the molecular regulation of G1 arrest of mouse thymocytes induced by ionizing radiation.Methods:Cell cycle was analyzed by flow cytomtry(FCM)following staining of cells with proidium iodide.Fluorescent staining and flow cytometry analysis were employed for measurement of protein expression.Results:it was demonstrated that G1 phase of mouse thymocytes increased significantly at 12h after whole body irradiation(WBI)with the doses of 0.5,1.0 and 2.0Gy,and at 24h following 2.0Gy exposure,measured by FCM.In the time course experiment,it was found that G1 phase of thymocytes increased significantly at 4h,reached a peak level at 24h and came down toward 48h after WBI with 2.0Gy X-rays.The results also showed that after 2.0Gy exposure,the expression of proteins in mouse thymocytes increased significantlty from 1h to 8h for p53,for p21 from 4h to 48h ,and for MDM2 at 4h and 8h.measured by FCM,But no change was found for GADD45 protein expression.Conclusion;These results suggest that G1 arrest could be induced by a single dose of 0.5Gy,1.0Gy or 2.0Gy,and its molecular control might be established through the p53-p21 pathway.     

G1 Arrest and Relative Protein Expressions in Mouse Thymocytes Induced by Whole Body X-Ray Irradiation G1 Arrest and Relative Protein Expressions in Mouse Thymocytes Induced by Whole Body X-Ray Irradiation

Objective　To investigate the molecular regulation of G1 arrest of mouse thymocytes induced by ionizing radiation. Methods　Cell cycle was analyzed by flow cytometry (FCM) following staining of cells with proidium iodide. Fluorescent staining and flow cytometry analysis were employed for measurement of protein expression. Results　It was demonstrated that G1 phase of mouse thymocytes increased significantly at 12h after whole body irradiation (WBI) with the doses of 0.5, 1.0 and 2.0 Gy, and at 24h following 2.0Gy exposure, measured by FCM. In the time course experiment, it was found that G1 phase of thymocytes increased significantly at 4h, reached a peak level at 24h and came down toward 48h after WBI with 2.0Gy X-rays. The results also showed that after 2.0Gy exposure, the expression of proteins in mouse thymocytes increased significantlty from 1h to 8h for p53, for p21 from 4h to 48h, and for MDM2 at 4h and 8h, measured by FCM. But no change was found for GADD45 protein expression. Conclusion　These results suggest that G1 arrest could be induced by a single dose of 0.5 Gy, 1.0Gy or 2.0Gy, and its molecular control might be established through the p53-p21 pathway.     

离辐射对小鼠EL-4淋巴瘤细胞caspase-3蛋白表达的影响

目的：观察电离辐射对caspase-3蛋白表达的影响。方法：采用体外传代培养的小鼠EL-4淋巴瘤细胞为实验材料；采用单克隆抗体免疫荧光标记，FACScan流式细胞仪(FCM)检测蛋白表达的变化；采用PI荧光标记及FCM测定细胞凋亡的变化；量效实验, 观察0.5、1.0、2.0、4.0及6.0 Gy X射线照射后24 h EL-4细胞caspase-3蛋白表达及细胞凋亡的变化；时效实验, 观察4.0 Gy照射后2、4、8、12、24、48及72 h EL-4细胞caspase-3蛋白表达的变化。结果：量效实验表明，0.5、2.0、4.0及6.0 Gy X射线照射后24 h EL-4细胞中caspase-3蛋白表达均明显增高，与假照射对照组比较，差异具有显著性 (P<0.05或P<0.01)。0.5、1.0及4.0 Gy 照射后24 h EL-4细胞凋亡明显增高，与假照射对照组比较，差异具有显著性 (P<0.05或P<0.01)。 时效实验表明，4.0 Gy照射后8、12及24 h EL-4细胞中caspase-3蛋白表达均明显增高, 与同时间点假照射对照组比较，差异具有显著性 (P<0.01或P<0.001)。结论：电离辐射可诱导EL-4细胞caspase-3蛋白表达增高。同时诱导EL-4细胞凋亡。     

X射线全身照射对小鼠脾细胞和腹腔巨噬细胞凋亡的影响

目的：观察不同剂量 X 射线全身照射对小鼠脾细胞和腹腔巨噬细胞凋亡的影响。方法：Annexin-V和PI双染后，采用流式细胞术检测小鼠脾细胞和腹腔巨噬细胞在照射后不同时间的细胞凋亡变化。结果：2 Gy X 射线全身照射与假照射组比较，小鼠脾细胞 凋亡百分率在照射后24 h明显升高（Ｐ< 0.05），腹腔巨噬细胞凋亡百分率从照射后4 h开 始明显升高（Ｐ< 0.05，Ｐ< 0.01），持续到48 h（Ｐ< 0.001）；0.075 Gy X 射 线全身照射与假照射组比较，小鼠脾细胞凋亡百分率在照射后24 h明显降低（Ｐ< 0.05）， 腹腔巨噬细胞凋亡百分率从照射后2 h开始至照射后16 h均有显著降低（Ｐ< 0.05）。 结论：较高剂量辐射促进小鼠脾细胞和腹腔巨噬细胞凋亡，而低剂量辐射对小鼠脾细胞和腹腔巨噬细 胞凋亡没有促进作用，并且能降低免疫细胞凋亡。     

Akt联合电离辐射对人乳腺癌MCF-7细胞凋亡、自噬和增殖的影响

目的: 通过检测Akt联合电离辐射对乳腺癌MCF-7细胞凋亡、自噬和增殖的影响,探讨以Akt为靶点的乳腺癌放射治疗作用。方法: 选择人乳腺癌MCF-7细胞、Akt过表达MCF-7(Akt-MCF-7)细胞和Akt低表达(Akt-RNAi-MCF-7) 细胞,实验分为MCF-7组、MCF-7+4 Gy组、Akt-MCF-7+4 Gy组和Akt-RNAi-MCF-7+ 4 Gy组 。3种细胞经4 Gy照射后,Western blotting法检测Akt蛋白表达,AnnexinⅤ-FITC和PI染色流式细胞术检测细胞凋亡率,MDC染色荧光显微镜观察细胞自噬百分比,MTT法检测细胞增殖活性。结果: 与MCF-7 细胞比较,Akt-MCF-7细胞中Akt蛋白表达强度增加,Akt-RNAi-MCF-7细胞中Akt蛋白表达强度降低。与MCF-7组比较,MCF-7+4 Gy、Akt-MCF-7+4 Gy和Akt-RNAi-MCF-7+4 Gy组细胞凋亡率和自噬百分比均明显增加(P<0.05或P<0.01),且以Akt-RNAi-MCF-7+4 Gy组增加最明显;与MCF-7+4 Gy组比较,Akt-MCF-7+4 Gy组细胞凋亡率和自噬百分比明显降低(P<0.05或P<0.01),而Akt-RNAi-MCF-7+4 Gy组细胞凋亡率和自噬百分比明显增加(P<0.05或P<0.01)。与MCF-7组比较,MCF-7+4 Gy组、Akt-MCF-7+4 Gy组和Akt-RNAi-MCF-7+4 Gy组细胞增殖活性在不同时间点均明显降低(P<0.05或P<0.01),Akt-RNAi-MCF-7+4 Gy组细胞增殖活性降至最低。与MCF-7+4 Gy组比较,Akt-MCF-7+4 Gy组细胞增殖活性在24 h时明显升高(P<0.05),而Akt-RNAi-MCF-7+4 Gy组细胞增殖活性在不同时间点均明显降低(P<0.01)。结论: Akt过表达可以显著降低电离辐射诱导的MCF-7细胞凋亡、自噬和增殖,而Akt低表达作用则相反。     

电离辐射对成纤维细胞中透明质酸蛋白及透明质酸酶1mRNA表达水平的影响

目的:观察电离辐射对成纤维细胞中透明质酸（HA）蛋白及透明质酸酶1（HAase1） mRNA表达水平的影响,并探讨其在放射性臂丛神经损伤发病机制中的作用。方法: 成纤维细胞分别采用0.5、1.0、2.0、4.0和6.0 Gy X射线照射,作为 5个剂量组,同时设假照射对照组（0 Gy）。透射电镜观察0、2.0、4.0和6.0 Gy X射线照射后48 h成纤维细胞的形态变化。采用ELISA法和RT-PCR法检测0、0.5、1.0、2.0、4.0、和6.0 Gy X射线照射后24及48 h成纤维细胞中HA蛋白及HAase1 mRNA表达水平的变化。结果：2.0 Gy X射线照射后48 h细胞染色质凝聚,有空泡形成;4.0 Gy X射线照射后48 h细胞核凹陷、染色质断裂;6.0 Gy X射线照射后细胞核凹陷、染色质固缩、出现空泡,部分胞浆溶解。不同剂量X射线照射后24 h HA蛋白表达均明显增高,与0 Gy组比较差异有统计学意义(P<0.05);0.5～2.0 Gy X射线照射后48 h HA蛋白表达变化不明显,4.0和6.0 Gy组与 0 Gy组比较,差异有统计学意义（P<0.05）。0～6.0 Gy X射线照射后24 h HAase1 mRNA水平明显增高,与0 Gy组比较,差异有统计学意义（P<0.05）。1.0、4.0和6.0 Gy X射线照射后48 h HAase1 mRNA水平明显增高,与0 Gy组比较,差异有统计学意义(P<0.05)。结论：电离辐射可诱导人成纤维细胞中HA蛋白表达和HAase1 mRNA水平增高,可能对放射性臂丛神经损伤的发生发展起到一定的作用。     

Effects of Corticosterone,. cAMP, cGMP, Ca^2＋, and Protein Kinase C on Apoptosis of Mouse Thymocytes Induced by X-ray Irradiation

Objective To observe the effects of signal factors of corticosterone （CS）, cAMP, cGMP, Ca^2＋ and protein kinase C （PKC） on lymphocyte apoptosis in mouse thymus induced by X-rays of 4 Gy in vitro. Methods The DNA lyric rate for thymocytes was measured by fluomspectrophotometry. Results The DNA lyric rate for thymocytes 4-8 hours after irradiation with 2-8 Gy was significantly higher than that in the control （P〈0.01）. As compared with the control, the DNA lyric rate for thymocytes treated with 0.01 μnol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.05-0.4 μg/mL ionomycin （Iono, P〈0.05 or P〈0.01） or 0.05-0.4 ng/mL phorbol myristate acetate （PMA, P〈0.05 or P〈0.01）, respectively, was significantly increased, while the rate for thymocytes treated with 50 ng/mL cGMP was not significantly increased. The DNA lyric rate for thymocytes treated with 0.01 μmol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.2 and 0.4 μg/mL Iono （P〈0.05）, and 0.2 and 0.4 ng/mL PMA （P〈0.05） plus 4-Gy irradiation, respectively, was significantly higher than that treated with single 4-Gy irradiation, while the rate for thymocytes treated with 50 ng/mL cGMP plus 4-Gy irradiation was not increased. When both 0.4 I.tg/mL Iono and 0.4 ng/mL PMA acted on the thymocytes, the DNA lyric rate for thymocytes was significantly higher than that in the control （P〈0.01）, the DNA lytic rate for thymocytes treated with both 0.4 μg/mL Iono and 0.4 ng/mL PMA plus 4-Gy irradiation was significantly higher than that treated with single 4-Gy irradiation （P〈0.05）, but was Iono plus 4-Gy irradiation or 0.4 ng/mL PMA plus 4-Gy irradiation. can promote thymocyte apoptosis induced by larger dose X-rays. not significantly higher than that treated with 0.4 μg/mL Conclusion CS, cAMP, Ca^2＋, and PKC signal factors can promote thymocyte apoptosis induced by larger dose X-rays.     

褪黑素对小鼠胸腺细胞电离辐射损伤的防护作用

目的：探讨外源性褪黑素（MLT）对电离辐射所致小鼠胸腺细胞损伤的影响及其机制。 方法：通过腹腔注射方式给予昆明系小鼠外源性MLT,分别建立单次给药和连续给药两种动物模型。对于单次给药动物模型,腹腔注射不同浓度MLT后60 min给予1 Gy X射线全身照射,12 h后采用流式细胞术和荧光分光光度法分别检测胸腺细胞凋亡小体百分率和DNA裂解率的变化;对于连续给药动物模型,连续1周腹腔注射不同浓度MLT后给予1 Gy X射线全身照射,24 h后检测胸腺细胞数量及³H-TdR掺入率的变化。 结果：单次给药动物模型,小鼠受1 Gy X射线全身照射后12 h,胸腺细胞数显著低于假照组（P<0.001）,凋亡小体百分率和DNA裂解率显著高于假照组（P<0.001）。照射前预先给予外源性MLT,与0 mg•kg^-1 MLT组（单纯照射组）比较,胸腺细胞数增多,以0.5 mg•kg^-1 MLT组增多最明显（P<0.01）;凋亡小体百分率和DNA裂解率降低,在0.1~2.5 mg•kg^-1 MLT浓度范围内差异均具有显著性（P<0.001）。连续给药动物模型,小鼠受1 Gy X射线全身照射后24 h,胸腺细胞数及³H-TdR掺入率均显著低于假照组（P<0.001）。照射前预先给予外源性MLT,与单纯照射组相比,胸腺细胞数和³H-TdR掺入率均显著增多,前者在0.01~0.10 mg•kg^-1 MLT浓度范围内差异具有显著性（P<0.01）,后者在0.1~1.0 mg•kg^-1 MLT浓度范围内差异均有显著性（P<0.05）。 结论：照射前预先给予外源性MLT可减轻电离辐射所致小鼠胸腺细胞损伤,对小鼠免疫功能具有保护作用。     

电离辐射和5-氟尿嘧啶对EL-4细胞周期的解偶联作用

目的：研究电离辐射和5-氟尿嘧啶（5-FU）对EL-4细胞周期解偶联的时间-效应关系和剂量-效应关系。方法：取指数生长期EL-4细胞,采用不同照射剂量（0、1.0、2.0和4.0 Gy）电离辐射和不同浓度5-FU（0、0.001、0.010、0.100和1.000 mg•L^-1）处理EL-4细胞,于0、4、8、16、24和48 h后分别收集细胞,碘化丙啶（PI）荧光标记及流式细胞术（FCM）检测细胞倍体变化。结果：与假照组比较,2.0 Gy X射线照射后,EL-4细胞二倍体细胞百分率在照射后8~24 h显著增加（P<0.05或P<0.01）,48 h恢复至正常水平;四倍体细胞百分率在照射后8~48 h显著降低（P<0.05或P<0.01）;八倍体细胞百分率在照射后16~24 h显著降低（P<0.05）。1.0~4.0 Gy X射线照射后16 h,与假照组比较,二倍体细胞百分率剂量依赖性增加（P<0.05或P<0.01）,四倍体细胞百分率呈剂量依赖性下降（P<0.01）,八倍体细胞百分率变化不显著。0.100 mg•L^-1 5-FU 给药后,与0 mg•L^-1组比较,EL-4细胞二倍体细胞百分率在给药后16~48 h显著降低（P<0.01）;四倍体细胞百分率在给药后8~24 h显著增加（P<0.05 或 P<0.01）,48 h回降;八倍体细胞百分率在给药后4~16 h显著增加（P<0.05）。不同剂量5-FU给药后16 h,与0 mg•L^-1组比较,EL-4细胞二倍体细胞百分率显著降低（P<0.05或P<0.01）,四倍体细胞百分率显著增加（P<0.05或P<0.01）,二者变化在0.001~1.000 mg•L^-1剂量范围内呈剂量依赖性;八倍体细胞百分率仅在0.010和0.100 mg•L^-1组显著增加（P<0.05或P<0.01）。结论：1.0~4.0　Gy电离辐射无诱导EL-4细胞发生细胞周期解偶联作用,0.010~0.100 mg•L^-1 5-FU可以诱导EL-4细胞发生细胞周期解偶联。     

Effect of X-rays on expression of caspase-3 and p53 in EL-4 cells and its biological implications

Objective To investigate the effect of X-rays on expression of caspase-3 and p53 protein in EL-4 cells and its implications in induction of apoptosis and polyploid cells. Methods Mouse lymphoma cell line （EL-4 cells） was used. Fluorescent staining and flow cytometry analysis were employed for measurement of protein expression, apoptosis, cell cycle, and polyploid cells. Results The expression of caspase-3 protein increased significantly at 8 h and 12 h, compared with that of sham-irradiated control （P〈0.05, respectively） and the expression of p53 protein increased significantly at 2, 4, 8, 12, and 24 h, compared with that of sham-irradiated control （P〈0.05-P〈0.01） in EL-4 cells after 4.0 Gy X-irradiation. Apoptosis of EL-4 cells was increased significantly at 2, 4, 8, 12, 24, 48, and 72 h after 4.0Gy exposure, compared with that of sham-irradiated control （P〈0.05-P〈0.001）. G2 phase cells were increased significantly at 4, 8, 12, 24, 48, and 72 h （P〈0,05-P〈0.001）. However, no marked change in the number of 8 C polyploid cells was found from 2 to 48 h after 4.0 Gy exposure. Conclusion The expressions of caspase-3 and p53 protein in EL-4 cells are induced by X-rays, which might play an important role in the induction of apoptosis, and the molecular pathway for polyploid formation might be p53-independent.     

X射线全身照射对小鼠胸腺细胞p53、p21、GADD45及MDM2蛋白表达的影响

目的：观察电离辐射全身照射对小鼠胸腺细胞ｐ５３、ｐ２１、ＧＡＤＤ４５ 及ＭＤＭ２ 蛋白表达的影响。方法：采用间接免疫荧光标记,流式细胞术检测蛋白表达的变化。结果：２ Ｇｙ Ｘ射线照射后１～８ ｈ ｐ５３ 蛋白表达显著增高;照射后４～４８ ｈ ｐ２１ 蛋白表达显著增高;ＭＤＭ２ 蛋白在照后４ ｈ 及８ ｈ 显著增高;而ＧＡＤＤ４５ 蛋白表达在照后１～４８ ｈ 内无明显变化。结论：电离辐射可诱导胸腺细胞ｐ５３、ｐ２１ 及ＭＤＭ２ 蛋白表达增高。此结果将对辐射诱导胸腺细胞Ｇ１ 期阻滞的分子通路研究有重要意义。     

尾叶香茶菜二萜类化合物B对人宫颈癌细胞的生长抑制作用及其机制

目的:观察尾叶香茶菜二萜类化合物B(DB)对人宫颈癌细胞株Hela细胞的生长抑制作用并探讨其机制。方法:处于对数生长期的Hela细胞分为正常对照组,0.5、1.0、2.0、4.0、8.0、16.0、32.0mg.L-1DB实验组,MTT法观察不同剂量DB作用24和48h后Hela细胞增殖抑制率,相差显微镜观察DB作用后Hela细胞形态的改变,RT-PCR和Western blotting分别观察DB作用后Hela细胞P53、P21、CDK2mRNA和蛋白表达水平。结果:MTT检测,24h时2.0、4.0、8.0DB组Hela细胞增殖抑制率分别为18.18%、28.89%和32.84%,48h时2.0、4.0、8.0DB组Hela细胞增殖抑制率分别为26.64%、47.03%和51.90%,呈时间-剂量依赖性(P<0.05或P<0.01);形态学观察,DB作用后Hela细胞变圆、体积缩小,有部分细胞漂浮;2.0、4.0和8.0mg.L-1DB分别作用Hela细胞24和48h后,P53和P21mRNA和蛋白表达水平明显高于正常对照组(P<0.01),CDK2mRNA和蛋白表达水平明显低于正常对照组(P<0.01)。结论:DB可抑制Hela细胞生长,其机制可能与上调细胞周期相关基因p53、p21的表达,下调CDK2表达,从而影响细胞从G1期进入S期有关。     

pshuttle-Egr-1-hSmac质粒联合X线照射对乳腺癌MDA-MB-435细胞增殖的抑制作用

目的:构建pshuttle-Egr-1-hSmac质粒并转染人乳腺癌MDA-MB-435细胞,观察其抑制肿瘤细胞的辐射增敏作用。方法：转染pshuttle-Egr-1-hSmac质粒的MDA-MB-435细胞经过2 Gy X线照射不同时间（4、8、12、24 和48 h）和0.5 ~ 5.0 Gy X线照射后24 h收集细胞,采用RT-PCR和Western blotting法检测Smac mRNA及其蛋白表达。将细胞分为对照组、pshuttle质粒组、pshuttle-Egr-1-hSmac 质粒组、2 Gy 组、pshuttle+2.0 Gy组 和pshuttle-Egr-1-hSmac+ 2.0 Gy组,MTT法检测各组细胞增殖;克隆形成实验检测细胞存活能力;Annexin Ⅴ-FITC双染法检测细胞凋亡;PI单染法检测细胞周期。结果:对照组和pshuttle质粒组MDA-MB-435细胞中Smac mRNA无表达,而pshuttle-Egr-1-hSmac质粒组MDA-MB-435细胞Smac mRNA表达水平随时间延长逐渐升高,于24和48 h时表达水平最高;经0.5 ~ 5.0 Gy X线照射后24 h MDA-MB-435细胞Smac mRNA表达水平随照射剂量增加而逐渐增加,在2.0和5.0 Gy X线照射后Smac mRNA表达水平最高。pshuttle-Egr-1-hSmac质粒组4、8、12和24 h后Smac蛋白表达水平逐渐升高,24 h后表达水平最高。经过0、0.5、1.0、2.0和5.0 Gy X线照射后24 h Smac蛋白表达水平逐渐升高,尤其以5.0 Gy X线照射时表达水平最高。MTT法检测时程效应,2.0 Gy、pshuttle+2.0 Gy和pshuttle-Egr-1-hSmac+2.0 Gy质粒组24、48和72 h细胞A490值明显低于对照组（P<0.01）;剂量效应,pshuttle-Egr-1-hSmac质粒组1.0～5.0 Gy X线照射后,MDA-MB-435细胞A490值明显低于0 Gy X线照射(P<0.05或P<0.01)。pshuttle-Egr-1-hSmac质粒组细胞存活分数明显低于对照组（P<0.01）。pshuttle-Egr-1-hSmac+2.0 Gy组细胞凋亡率明显高于2.0 Gy组（P<0.01）,G0/G1期和S期细胞百分率明显低于2.0 Gy照射组（P<0.01）,G2/M期细胞百分率明显高于2.0 Gy组（P<0.01）。结论：X线照射能增加pshuttle-Egr-1-hSmac质粒转染的MDA-MB-435细胞有效表达Smac mRNA及蛋白,能抑制细胞存活,且诱导G2/M期阻滞和凋亡增加;Smac基因联合放射治疗可明显增加乳腺癌细胞的放射敏感性。     

褪黑素对电离辐射诱导离体小鼠淋巴细胞凋亡的影响

目的：探讨褪黑素（melatonin,MLT）对电离辐射诱导的离体小鼠淋巴细胞凋亡的影响及其机制。 方法：采用流式细胞术（FCM）和荧光分光光度法分别检测小鼠胸腺和脾淋巴细胞凋亡小体百分率和DNA裂解率。 结果：电离辐射可诱导离体小鼠胸腺、脾淋巴细胞凋亡,在0.5~6.0 Gy范围内凋亡呈剂量依赖性增加。照射前预先加入2 mmol•L^-1MLT,细胞凋亡小体百分率和DNA裂解率与单纯照射组比较均显著降低,胸腺、脾淋巴细胞凋亡小体百分率分别降低为单纯照射组的86.25%和89.22%,DNA裂解率分别降低为单纯照射组的87.23%和89.16%。 结论：MLT在体外可减轻电离辐射诱导的小鼠淋巴细胞凋亡,对淋巴细胞损伤有防护作用。     

电离辐射对Jurkat T细胞凋亡与坏死的影响

目的：研究电离辐射诱导Jurkat T细胞凋亡与细胞坏死的变化规律,探讨电离辐射作用后细胞的死亡模式与机理。方法：采用Annexin V-EGFP和PI 双染、流式细胞术(FCM)检测不同剂量（0.075、0.500、1.000、2.000、4.000和6.000 Gy）X射线照射后Jurkat T细胞凋亡与细胞坏死的时间-效应关系和剂量-效应关系。结果：时间-效应关系,2.000 Gy X射线照射后,与假照组比较,Jurkat细胞凋亡百分率在照射后18 h显著增加,至24 h始终维持在较高水平（P＜0.001）;细胞坏死百分率于照射后4 h显著增加,12 h 达峰值,至48 h始终维持在较高水平（P＜0.001）。剂量-效应关系,0.075Gy X射线照射后18 h,Jurkat T细胞凋亡百分率和细胞坏死百分率与假照组相比较未见明显变化（P＞0.05）。2.000~6.000 Gy较大剂量X射线照射后18 h,细胞凋亡百分率和细胞坏死百分率与假照组比较均呈剂量依赖性增加（P＜0.001）。结论：2.000 Gy以上剂量X射线可以诱导Jurkat T细胞发生凋亡和坏死,细胞坏死比细胞凋亡出现时间更早,持续时间更长。     

电离辐射对Jurkat T细胞周期进程的影响

目的：探讨电离辐射诱导Jurkat T细胞损伤过程中细胞周期进程的变化规律。方法：采用流式细胞术 (FCM) 检测低剂量（0.075 Gy）和较大剂量（0.5、1.0、2.0、4.0及6.0 Gy）X射线照射后Jurkat T细胞周期进程变化的时间-效应关系和剂量-效应关系。结果：时间-效应关系研究发现,2.0 Gy X射线照射后Jurkat T细胞相继发生S期延迟和G₂期阻滞,S期细胞百分率于照射后立即增加(P<0.001),而G₂+M期细胞百分率照射后8 h开始显著增加（P<0.001）。剂量-效应关系研究发现,75 mGy低剂量X射线照射即可诱导Jurkat T细胞发生S期延迟（P<0.001）和G₂期阻滞（P<0.05）;0.5~6.0 Gy较大剂量X射线照射后,Jurkat T细胞发生S期延迟和G₂期阻滞。与假照组相比较,G₀/G₁期细胞百分率显著降低（P<0.001）,在0.5~6.0 Gy内具有剂量依赖性,而S期和G₂+M期细胞百分率显著升高（P<0.05或P<0.001）。结论：X射线照射可以改变Jurkat T细胞周期进程,诱导其相继发生S期延迟和G₂期阻滞,在0.5~6.0 Gy内具有剂量依赖性。     

电离辐射对小鼠腹腔巨噬细胞TLR4和转接蛋白MyD88表达的影响

目的：观察电离辐射对小鼠腹腔巨噬细胞TLRs介导的信号传导通路中TLR4和转接蛋白MyD88表达的影响,探讨低剂量辐射诱导机体免疫效应的机制。方法：昆明系雄性小鼠160只。时间-效应实验60只,随机分为假照组、照射后4、8、16、24和48 h实验组,每组10只;剂量-效应实验100只,随机分为假照组、0.050、0.075、0.100、0.200、0.500、1.000、2.000、4.000和6.000 Gy照射组,每组10只;X 线全身照射 (WBI) 后,采用流式细胞术检测小鼠腹腔巨噬细胞中TLR4和MyD88阳性细胞百分率。结果：时间-效应实验表明,与假照组比较,0.075 Gy 照射后TLR4和MyD88表达率在4 h后开始增高,分别在16 h和4 h达高峰（P<0.05或P<0.01,）;2.000 Gy 照射后,TLR4和MyD88表达率在4 h后开始增高, 16 h达高峰（P<0.01）。剂量-效应实验表明,与假照组比较,各剂量照射组 TLR4和MyD88表达率均随照射剂的增加递增,在0.075 Gy 开始明显增加（P<0.05）,在2.000 Gy 照射后达高峰（P<0.01）。结论：电离辐射使小鼠腹腔巨噬细胞TLR4和转接蛋白MyD88表达增高,促进小鼠的免疫反应,启动固有免疫及适应性免疫。     

p16在人脑胶质瘤中的表达及其意义

目的: 探讨p16在脑胶质瘤中的表达及其意义。方法: 采用免疫组织化学、核酸原位杂交和多重PCR的方法,检测68例脑胶质瘤和10例正常脑组织标本中p16的表达。结果: p16和mRNA在胶质瘤Ⅰ～Ⅱ级和Ⅲ～Ⅳ级的阳性表达,差异均有统计学意义(P<0.01～P<0.005),而多重PCR检测p16在胶质瘤Ⅰ～Ⅱ级和Ⅲ～Ⅳ级的阳性表达,差异无统计学意义(P>0.05)。结论: p16基因缺失可能与胶质瘤的发生有关;p16低表达在人脑胶质瘤的恶性进展中起重要作用,可作为预后评估指标之一。