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目的研究硒对镉诱导的大鼠肝细胞端粒酶活力、癌基因c-myc和p53表达的影响。方法 80只雄性SD大鼠随机分为16组,包括对照组,2.5、5.0和10.0μmol/kg亚硒酸钠组,5.0、10.0和20.0μmol/kg氯化镉组,9个硒镉联合作用组。氯化镉采用腹腔注射染毒、亚硒酸钠采用灌胃染毒。用端粒重复序列扩增法(TRAP)检测端粒酶活力,用逆转录聚合酶链反应法检测c-myc和p53表达。结果 3个镉单独作用组的大鼠肝细胞端粒酶活力、c-myc和p53表达较对照组明显增高,差异有统计学意义(P<0.05)。硒镉联合作用组中,当2.5和5.0μmol/kg亚硒酸钠分别与5.0、10.0和20.0μmol/kg氯化镉联合作用时,大鼠肝细胞端粒酶活力、c-myc和p53 mRNA水平较相应剂量的镉单独作用组下降;当10.0μmol/kg亚硒酸钠分别与5.0、10.0和20.0μmol/kg氯化镉联合作用时,大鼠肝细胞端粒酶活力、c-myc和p53 mRNA水平与相应剂量的镉单独作用组比较,差异无统计学意义(P>0.05)。结论相对较低剂量的硒对镉引起的大鼠肝细胞端粒酶活力增高具有抑制作用,其抑制作用可能是通过降低c-myc和p53表达。
Objective To study the effect of selenium on cadmium-induced telomerase activity, oncogene c-myc and p53 expression in rat hepatocytes. Methods Eighty male Sprague-Dawley rats were randomly divided into 16 groups, including control group, 2.5, 5.0 and 10.0 μmol / kg sodium selenite group, 5.0, 10.0 and 20.0 μmol / kg cadmium chloride group, group. Cadmium chloride injection by intraperitoneal injection, selenite sodium gavage. Telomerase activity was detected by telomeric repeat amplification (TRAP) and c-myc and p53 were detected by reverse transcription-polymerase chain reaction (RT-PCR). Results The expression of telomerase activity, c-myc and p53 in hepatocytes of 3 cadmium groups were significantly higher than those in control group (P <0.05). In selenium-cadmium combined group, the activities of telomerase, c-myc and p53 mRNA in rat hepatocytes were significantly increased when 2.5 and 5.0 μmol / kg sodium selenite were combined with 5.0, 10.0 and 20.0 μmol / kg cadmium chloride The level of cadmium decreased compared with the corresponding dose of cadmium alone; when 10.0μmol / kg sodium selenite was combined with 5.0,10.0 and 20.0μmol / kg cadmium chloride respectively, the telomerase activity, c-myc and There was no significant difference in p53 mRNA level between the two groups (P> 0.05). Conclusions Selenium at a relatively low dose can inhibit the increase of telomerase activity in rat hepatocytes induced by cadmium, and its inhibitory effect may be through decreasing the expression of c-myc and p53.