Objective:To investigate the specific interference of OX40 gene expression induced by RNAi technique in 293T cell lines transfected with rat OX40 gene.Methods:293T cells were transfected with recombined plasmid pEGFP-N1-GFP/OX40,and the positive cell clones were selected by fluorescence protein observation and RT-PCR.One specific dicer siRNA targeted to OX40 mRNA was designed and synthesized,which shared no homology with exons of known human gene.Quantitative real-time PCR was performed to measure the inhibitory rate of target gene expression by comparing OX40 mRNA concentrations before and after siRNA transfection.Results:10 nmol/L siRNA-OX40 elicited the highest level of gene silence in 293T cells which was transfected with siRNA after 48 h (68.3?8.7)%);The time of maximal inhibitory effect was at 48-72 h [(61.7?8.4)%,(39.6?5.6)%].Conclusion:The exogenous OX40 expression can be significantly inhibited by treatment with specific siRNA in a dose and time -dependent manner in 293T cells,which may provide a useful profile for further investigation of inhibition of OX40 protein,and a promising control approach for preventing immune reaction.

Objective To summarize the clinical experience of liver transplantation in the treatment of hepatocellular carcinoma(HCC).Methods From June 2004 to March 2007,70 consecutive HCC patients underwent liver transplantation in our hospital,including classic orthotopic liver transplantation in 41 cases,and piggyback liver transplantation in 29 cases.All data of patients were retrospectively analyzed.Results All liver transplantation were successfully conducted.The average warm ischemia duration was 4.5 minutes,and cold ischemia duration was 8 hours.There were 3 cases of postoperative deaths.Surgical complications were intra-abdominal hemorrhage in 2 cases,and biliary anastomotic stricture in 4 cases.Sixty-seven cases were followed up for 12-33(average 21) months,10 cases had recurrence of liver cancer after transplatation and 1 dead.Conclusions Liver transplatation can used on selected patients with HCC.Successful liver transplantation relies on good quality of liver graft,and idealized technique of vascular and bile duct reconstruction are key factors of liver transplantation.Proper postoperative management can effectively reduce the complications of operation.

Objective To investigate the effect of blockading OX40-OX40L co-stimulatory signaling on the survival time of liver allograft in rat.Methods siRNA-expression vectors were constructed to targeting OX40.3～5 minutes before DA to Lewis orthotopic liver transplantation was performed,5×109 pfu of targeting OX40 siRNA plasmid DNA were diluted in 5 ml of phosphate buffered saline(PBS)and inlected intravenously into recipient Lewis rat over a period of 10 seconds.Serum IL-2 and IFN-γ levels were assayed by ELISA,and mix lymphocyte response(MLR)were tested by 3H-thymidine.Results The survival time of recipients in siRNA treatment group(74.0±9.3)was significantly longer than that in control group[(7.3±0.5)days].In experiment group,the inflammatory cell infihration and liver tissue structure destruction were very slight.The concentration of serum IL-2 was much lower in siRNA treatment group[(46±8.4)pg/ml]than that in control group[(286.5±14.6)pg/ml].Meanwhile,the concentration of serum IFN-γ was much lower in siRNA treatment group [(202.7±14.6)pg/ml]than that in control group[(1682.7±87.9)pg/ml].Conclusion Administration of OX40-siRNA can blockade OX40-OX40L co-stimulatory signaling pathway.hence inhibit the rejection of liver allograft.