Telomerase activity and telomerase reverse transcriptase expression induced by selenium in rat hepatocytes.
OBJECTIVE
To investigate the effects of sodium selenite on telomerase activity, apoptosis and expression of TERT, c-myc and p53 in rat hepatocytes.


METHODS
Selenium at doses of 2.5, 5.0, and 10 micromol/kg was given to SD rats by gavage. In rat hepatocytes, telomerase activity was measured by the telomeric repeat amplification protocol (TRAP), apoptosis was detected by flow cytometry, and expressions of telomerase reverse transcriptase (TERT), c-myc and p53 were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). c-Myc and P53 proteins were detected by immunochemistry.


RESULTS
Selenium at doses of 2.5, 5.0, and 10 micromol/kg significantly increased hepatocellular telomerase activity and induced apoptosis in a dose-dependent manner. Although selenium at doses of 2.5, 5.0, and 10 micromol/kg displayed no obvious enhancing effect on the TERT mRNA expression in rat hepatocytes (P > 0.05), it significantly increased the c-myc mRNA and p53 mRNA expression at the dose of 10 micromol/kg (P < 0.05). Selenium at doses of 5.0 and 10 micromol/kg obviously increased the content of P53 protein in rat hepatocytes, but only at the dose of 10 micromol/kg, it significantly promoted the value of c-Myc protein in them.


CONCLUSIONS
Selenium can slightly increase telomerase activity and TERT expression, and significantly induce apoptosis and over-expression of c-myc and p53 at relatively high doses. The beneficial effects of selenium on senescence and aging may be mediated by telomerase activation and expression of TERT, c-myc, and p53 in rat hepatocytes.
Yu
Ri-An
RA
Department of Occupational and Environmental Health, School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, Guangdong, China. yurian_tj@yahoo.com.cn
Chen
Hua-Jie
HJ
He
Ling-Fei
LF
Chen
Bing
B
Chen
Xue-Min
XM
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D008297:Male; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012643:Selenium / Q000494:pharmacology*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D016159:Tumor Suppressor Protein p53; D019098:Telomerase; D012643:Selenium