ABSTRACT
Objective To study the possible molecular mechanism of the damage of HepG2 cell line induced by low concentration of ethanol and ultraviolet irradiation. Methods Hepatoma cell line (HepG2) was exposed to low concentration of ethanol and ultraviolet irradiation, then the changes in cell cycle, the expression of p53 and p21, the correlation between expression of p53 and p21 and cell cycle were analyzed. Results The expression of p53 and p21 was greatly increased, and the cell cycle was found to be blocked at G_0-G_1/G_2-M after ultraviolet irradiation. The cell cycle block of G_2-M and the increased expression of p21 were observed when exposed to low concentration of ethanol, while the expression of p53 showed no significant changes. Cell apoptosis was increased when the cells were exposed to the both injury factors. Conclusion Low concentration of ethanol and ultraviolet irradiation can affect cell cycle and the process of cell apoptosis through activation of different molecular mechanism.
ABSTRACT
To observe whether there is an interaction between hepatitis virus B (HBV) and tumor suppressor p53, plasmid PCMVp53 was transfected or cotransfected with pCMVHBV a (wild type HBV) or PCMVHBV b (mutation type HBV) into the hepatoma cell line 7721 by phosphate calcium precipitation. Apoptosis cells were labeled by annexin Ⅴ FITC and detected by flow cytometry. Another experiment was performed by cotransfecting the cells with reporter plasmid p21 luc in each group mentioned above, then the luciferase activity was measured. The results showed that the cells transfected by pCMVp53 alone exhibited high luciferase activity and high apoptosis rate. Meanwhile, the luciferase activity and apoptosis rate were further higher in cells cotransfected by pCMVp53 and PCMVHBV a , but remained unchanged in cells cotransfected by PCMVp53 and PCMVHBV b. The results indicated that P53 could induce of 7721 cell apoptosis by activating p21 transcription, and such effect could be enhanced by HBV.
ABSTRACT
Objective To screen the down-regulated genes in HepG2 cells transfected by pcDNA3.1(-)-IFN-? to further investigate the biological mechanism of IFN-?. Methods pcDNA3.1(-)-IFN-? was transfected into HepG2 cells as treatment group and the pcDNA3.1(-) transfected cells as the control to perform suppression subtractive hybridization (SSH). The subtractive library for down-regulated genes was obtained when pcDNA3.1(-) transfected HepG2 as tester and pcDNA3.1(-)-IFN-? transfected cells as driver. A housekeeping gene, G3PDH, was used to estimate the subtractive efficiency. Genes with lower expressions in IFN-? transfected HepG2 cells were obtained from the library after being randomly sequenced and analyzed. Among the obtained genes, regulation of IFN-? on heat shock 90kD (Hsp90) mRNA was further investigated by RT-PCR. Results G3PDH was subtracted efficiently indicating that the subtractive library was constructed successfully. 50 positive clones were randomly isolated for PCR identification. Results showed that most of the plasmids in the clones contained 200-1 000bp inserts. The down-regulated genes obtained were as follows: eukaryotic translation elongation factor 1 beta, ferritin, RAD23 homolog B, signal sequence receptor 2 (SSR2), tissue factor pathway inhibitor, heat shock 90kD protein 1, and adenosylmethionine decarboxylase 1. RT-PCR showed that hsp90 mRNA had a reduced expression in pcDNA3.1 (-)-IFN-? transfected HepG2 cells. Conclusion The down-regulated cDNA subtractive library in HepG2 cells after pcDNA3.1 (-)-IFN-? transfection was constructed successfully. IFN-? could down-regulate the hsp90 mRNA expression.
ABSTRACT
To study the effect of heparin on the ConA induced acute liver injury inKunming mice,twenty four mice were randomly divided into groups A,B and C.To the mice in group A, 0 2ml of normal saline (NS) was intravenously administered, while those in group B were given ConA 18mg/kg instead of NS in order to induce severe acute liver injury. Heparin was injected subcutaneously in a dose of 100U per animal at the same time as ConA challenge in group C. Compared with group B, prior injection of heparin in group C significantly decreased the mice death rate and the peak levels of serum ALT within 8h. At the same time, intrasinusoidal congestion and hepatic inflammation were alleviated significantly,and MDA level in liver homogenate was lowered markedly. It suggested that heparin is efficient in protecting the mice from liver injury induced by ConA.