大鼠肝癌形成过程MCM7基因动态变化

目的：4g讨MCM7基因在黄曲霉毒素B1（AFB1）实验诱发大鼠肝癌过程中的动态变化及意义。方法：将70只雄性4周龄Wistar大鼠随机分为AFB1组（50只）和对照组（20只），AFB1组腹腔注射AFB1，对照纽则给予溶媒二甲基亚砜。在诱发肝癌过程中，分别于第13、33和53周对大鼠进行肝活检；实验至第73周处死全部大鼠取肝组织；采用实时荧光定量PCR、蛋白质印迹法和免疫组化方法检测肝组织中MCM7rnRNA和蛋白的表达情况。结果：AFB1组肝细胞癌发生率为44．1％（15／a4），对照组为0（0／16），AFB1组显著高于对照组，χ^2=8．093，P〈0．001。随着大鼠肝癌的形成，MCM7mRNA和蛋白的表达水平逐步升高，AFB1组第53和73周显著高于第13和33周，F值分别为55．632和207．253，P值均〈0．001；对照组各时间点的表达较低且变化不大。免疫组化结果显示，AFB1组第53周McM7蛋白阳性表达率为26．7％且以弱阳性为主，第73周MCM7蛋白阳性表达率为100％且多为强阳性，阳性表达率和表达强度均比其他时间点的高，两者比较差异均有统计学意义，P值均〈0．001。结论：MCM7表达水平随着肝癌的形成逐渐上升，且在肝癌组织中表达最高，MCM7有可能是参与肝癌形成的关键基因，但其详细机制有待进一步探讨。

Dynamic change of MCM7 during hepatocarcinogenesis in rat

OBJECTIVE： To investigate the dynamic change of minichromosome maintenance complex component 7 （MCMT） in hepatocarcinogenesis induced by aflatoxin B1 （AFB1） in rats. METHODS：Seventy Male and 4-weeks old Wist ar rats were divided randomly into AFBI（50） and control groups（20）. Rats in AFB1 group were injected intraperitoneally with AFB1 and solvent DMSO, and control groups were given DMSO. During hepatocarcinogenesis, liver biopsies were performed on all animals at 13th, 33rd, 53rd-week of the experiment. Animals were sacrificed at the 73rd-week and liver tissues were collected. The expression of MCM7 mRNA of hepatocyte were detected by Real-time PCR and the relative protein expression in liver tissue were observed by Western Blot and Immunohistochemistry array. RESULTS： Hepatocellu lar carcinoma incidence in AFB1 group was 44.1 % （15/34） and in control group was 0;the hepatocellular carcinoma inci dence was significantly higher in AFB1 group than that in control group （χ^2=8. 093, P〈0. 001）. With the formation of liver cancer in rats,the expression of MCMTmRNA and the relative protein expression were gradually increased. The ex pression of MCMTmRNA and the relative protein expression in AFB1 group were both significantly higher in 53rd-and 73rd-week than that in 13th-and 33rd-week of the experiment （F= 55. 6ae, 207. 253,P〈0. 001）. The expression of MCM7 mRNA and the relative protein expression in control groups had no changes in whole experiments. The results show in Immunohistochemical array, the expression of MCM7 protein positive rate was 100% in AFB1 group at 73rd weeks and 26.7 %at 53rd weeks. The positive expression rate and expression intensity were higher than that of the other point in time in AFB1 group at 73rd weeks （P〈0. 001）. CONCLUSIONS：The expression of MCMTmRNA and the relative protein expression were gradually increased during hepatocarcinogenesis induced by AFB1 in Rats, and were the highestand expressed in liver cancer tissue. MCM7 may Play a pivotal role in hepatocarcinogenesis and its mechanism remains to be further discussed in detail.