N/A. N/A

Prolonged survival of rat hepatic allograft after pretransplant intraportal infusion of recipient blood to the donor

AIM: To investigate the effect of pretransplant intraportal administration of recipient blood into the donor on the survival of rat hepatic allograft.

METHODS: Male LEW (RT1) and ACI (RT1^a) rats were used as liver transplant recipients and donors, respectively. In experimental group, 7 d prior to transplantation, ACI donors were anesthetized with ether and transfused with freshly heparinized LEW recipient blood (1 mL) via the portal vein. In control group, the rats only received 1 mL normal saline 7 d before transplantation. The serum levels of interferon-γ (IFN-γ) were determined after transplantation. Immunocompetent cells from the donors were identified with anti-donor classⅡ MHC (RT1B^a) (OX-76) antibodies. The number of donor-derived CD4⁺ and CD8⁺ T cells in hepatic allograft or recipient spleen was examined. Reverse transcription-polymerase chain reaction was used to detect the mRNA expression of cytokines in the allograft.

RESULTS: LEW rats transplanted with hepatic allograft from ACI rats survived a mean of 11.1 ± 2.1 d. Intraportal preadministration of recipient LEW blood significantly increased the survival of LEW recipients with ACI livers to 31.7 ± 7.6 d (P < 0.05). The serum level of IFN-γ was significantly increased in the experimental group as compared with that in the control group. Cellular infiltration of the hepatic allograft in experimental group was significantly lower than that in the control group. The ratio of OX76⁺CD4⁺ or OX76⁺CD8⁺ T cells to CD4⁺ or CD8⁺ cells was significantly greater in hepatic allograft pretreated with LEW recipient blood than that in the controls (OX76⁺CD4⁺ cells: 25.6% vs 6.2%, P < 0.05; OX76⁺CD8⁺ cells: 26.6% vs 7.4%, P < 0.05), but not in recipient spleen. OX76⁺CD8⁺ T cells from hepatic allograft in the experimental group expressed IFN-γ and interleukin-10 mRNA, but not interleukin-2 mRNA.

CONCLUSION: Pretransplant intraportal infusion of recipient blood to the donor rats prolonged the survival of hepatic allograft, which may be associated with the regional graft-versus-host reaction.

Hydrogen peroxide induces apoptosis of human spleen cells in vitro

AIM: To investigate the dose- and time-effect of hydrogen peroxide (H₂O₂) on human spleen cells, and to establish a stable apoptotic model of human spleen cells.

METHODS: The human spleen cells, obtained by the method of grinding, were divided into four groups and treated with saline solution or various concentrations of H₂O₂ respectively. The function of mitochondrions was assessed by the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and the early apoptotic cells were detected by flow cytometry with a combination of Annexin V-FITC/PI.

RESULTS: H₂O₂ affected the mitochondrial function (negatively) and apoptosis (positively) of the human spleen cells in a dose- and time-dependent manner The apoptotic rates were significantly different between different groups (Total: 55.01±9.11%, 44.07±9.00%, 30.20±6.75% and 9.97±1.68% for 100, 50, 25 μmol/L and control group respectively, P<0.05). The apoptotic rate of cells reached the highest value (69.28±3.01)% at the concentration of 100 mmol/L 6 hours after treatment.

CONCLUSION: H₂O₂ can induce the apoptosis of human spleen cells in vitro, which can be used to establish apoptotic model.