This study investigated the effect of cadmium on the telomerase activity, the expression of TERT, c-myc and p53 and the apoptosis of rat hepatocytes. The rats were administrated 5, 10 and 20 μmol/kg cadmium chloride intraperitoneally and sacrificed 48 h after the initial treatment. The telomerase activity of the rat hepatocytes was measured by the telomeric repeat amplification protocol (TRAP), and apoptosis was detected by flow cytometry. The mRNA expressions of TERT, c-myc and p53 were measured by reverse transcription-polymerase chain reaction (RT-PCR). C-myc and P53 proteins were determined by immunochemistry. The results showed that cadmium chloride increased the hepatocellular telomerase activity in a dose-dependant manner and induced the apoptosis of hepatocytes significantly. The value of relative coefficient between the telomerase activity and the apoptosis rate was 0.9398. RT-PCR revealed that specific bands corresponding to the TERT mRNA, c-myc mRNA, and p53 mRNA were displayed at 185, 342 and 538 bp respectively. Cadmium chloride could substantially increase the mRNA expressions of TERT, c-myc and p53 in rat hepatocytes, as compared with control. Moreover, cadmium chloride at the doses of 5, 10 and 20 μmol/kg could increase the content of P53 protein in rat hepatocytes obviously, but only that at the doses of 10 and 20 μmol/kg substantially promoted the c-myc protein level in rat hepatocytes. Our study herein suggested that cadmium may contribute to the carcinogenesis by activating telomerase, and overexpressing the mRNAs of TERT, c-myc and p53, and causing apoptosis of normal cells.

This study investigated the effect of cadmium on the telomerase activity, the expression of TERT, c-myc and p53 and the apoptosis of rat hepatocytes. The rats were administrated 5, 10 and 20 μmol/kg cadmium chloride intraperitoneally and sacrificed 48 h after the initial treatment. The telomerase activity of the rat hepatocytes was measured by the telomeric repeat amplification protocol (TRAP), and apoptosis was detected by flow cytometry. The mRNA expressions of TERT, c-myc and p53 were measured by reverse transcription-polymerase chain reaction (RT-PCR). C-myc and P53 proteins were determined by immunochemistry. The results showed that cadmium chloride increased the hepatocellular telomerase activity in a dose-dependant manner and induced the apoptosis of hepatocytes significantly. The value of relative coefficient between the telomerase activity and the apoptosis rate was 0.9398. RT-PCR revealed that specific bands corresponding to the TERT mRNA, c-myc mRNA, and p53 mRNA were displayed at 185, 342 and 538 bp respectively. Cadmium chloride could substantially increase the mRNA expressions of TERT, c-myc and p53 in rat hepatocytes, as compared with control. Moreover, cadmium chloride at the doses of 5, 10 and 20 μmol/kg could increase the content of P53 protein in rat hepatocytes obviously, but only that at the doses of 10 and 20 μmol/kg substantially promoted the c-myc protein level in rat hepatocytes. Our study herein suggested that cadmium may contribute to the carcinogenesis by activating telomerase, and overexpressing the mRNAs of TERT, c-myc and p53, and causing apoptosis of normal cells.
Animals ; Apoptosis ; drug effects ; Cadmium ; toxicity ; Hepatocytes ; drug effects ; metabolism ; pathology ; Male ; Proto-Oncogene Proteins c-myc ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Telomerase ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism

Background: and Purpose We investigated the causal relationships between the gut microbiota (GM), stroke, and potential metabolite mediators using Mendelian randomization (MR). Methods: We leveraged the summary statistics of GM (n=18,340 in the MiBioGen consortium), blood metabolites (n=115,078 in the UK Biobank), and stroke (cases n=60,176 and controls n=1,310,725 in the Global Biobank Meta-Analysis Initiative) from the largest genome-wide association studies to date. We performed bidirectional MR analyses to explore the causal relationships between the GM and stroke, and two mediation analyses, two-step MR and multivariable MR, to discover potential mediating metabolites. Results: Ten taxa were causally associated with stroke, and stroke led to changes in 27 taxa. In the two-step MR, Bifidobacteriales order, Bifidobacteriaceae family, Desulfovibrio genus, apolipoprotein A1 (ApoA1), phospholipids in high-density lipoprotein (HDL_PL), and the ratio of apolipoprotein B to ApoA1 (ApoB/ApoA1) were causally associated with stroke (all P<0.044). The causal associations between Bifidobacteriales order, Bifidobacteriaceae family and stroke were validated using the weighted median method in an independent cohort. The three GM taxa were all positively associated with ApoA1 and HDL_PL, whereas Desulfovibrio genus was negatively associated with ApoB/ApoA1 (all P<0.010). Additionally, the causal associations between the three GM taxa and ApoA1 remained significant after correcting for the false discovery rate (all q-values <0.027). Multivariable MR showed that the associations between Bifidobacteriales order, Bifidobacteriaceae family and stroke were mediated by ApoA1 and HDL_PL, each accounting for 6.5% (P=0.028) and 4.6% (P=0.033); the association between Desulfovibrio genus and stroke was mediated by ApoA1, HDL_PL, and ApoB/ApoA1, with mediated proportions of 7.6% (P=0.019), 4.2% (P=0.035), and 9.1% (P=0.013), respectively. Conclusion The current MR study provides evidence supporting the causal relationships between several specific GM taxa and stroke and potential mediating metabolites.