Detection of TNF-related apoptosis inducing ligand gene expression by real-time fluorescent quantitative method

Objective To establish a real time fluorescent quantitative revers transcripatase PCR(FQ-RT-PCR) method to detect the expression level of TNF-related apoptosis inducing ligand (TRAIL) mRNA in peripheral blood mononuclear ceils (PBMC) and determine its expression level in healthy donors, HBV-caused cirrhosis patients and PBC ones. Methods Specific primers and Taqman-MGB probe were designed and β-actin was used as endogenous control. The amplified fragment was obtained by RT-PCR. The quantitative template was constructed and then the fluorescent intensity was documented on the ABI Prism7000 analyzer. The standard curve was established, according to which, the TRAIl. mRNA levels in 30 healthy individuals, 30 patients with primary biliary cirrhosis (PBC) and 25 ones with HBV-caused cirrhosis were calculated automatically by software after the values of cycle threshold (Ct) were detected continuously during amplification. Results The linear detection range of the assay for TRAIL gene was 103 - 109 copies/ ug RNA ( r=-0.997). The coefficients of variation of both intra-and inter-assay reproducibility for high concentration samples were 5.6% and 6. 3% , respectively, and those for low concentration samples were12.5% and 14. 6%. The TRAIL mRNA expression level in PBC patients was [ (3.3±2.5)×105copies/ugRNA] significantly higher than that of healthy control [ (0.5±0.2)×105 copies/ug RNA ] (t=5.994,P <0.01). TRAIl. mRNA level of HBV-caused cirrhosis patients[ (2.1±0.9)×105 copies/ug RNA] wasalso significantly elevated (t=8.536, P<0.01). However, the difference between these two diseased groups had no significance. Conclusion We have successfully set up a FQ-RT-PCR method for detecting TRAIL gene expression and found that its expression levels of peripheral blood mononuelear cells in PBC and HBV caused cirrhosis patients are elevated, which provides a new insight into mechanism study of liver injury caused by cirrhosis. Key words: Tumor necrosis factors;  Leukocytes, mononuclear;  Gene expression;  Reverse transcriptase polymerase chain reaction;  Membrane glycoproteins