Mechanism Of Inhibiting HDAC11 In The Induction Of Immune Tolerance In Rats

Objective: To study the mechanism of inhibiting HDAC11 in the induction of immune tolerance in rats and advantages of gene therapy over use of immunosuppressant FK506.Methods: Lewis to BN liver transplantation was performed by modified Kamada two-cuff method. The recipients were assigned to control group intervention group and transfection group. Transfection group were perfused with HDAC11-shRNA(2 mL) plasmid (pSIHDAC11) during cold ischemia phase through portal vein, control group received the equal NS, and the intervention group were treated with FK506 at a dose of 1 mg/kg per day by intramuscular injection starting on postoperative day 1 to 7 days. Acute rejection (AcR) was graded by the Banff scheme and postoperative survival was examined. Liver functions were determined by alanine aminotransferase (ALT), aspartase mainotransferase (AST) and total bilirubin (TBIL) measured with an automatic biochemical analyser. The mRNA and protein expressions of HDAC11 and IL-10 in liver tissue were detected by real-time PCR and western blot, respectively. Plasma levels of IL-2 IFN-γand IL-10 were assayed by Enzyme-Linked Immunosorbent. Results: (1) Models of Lewis to BN LT was successfully established. The survive rates of control group, intervention group and transfection group were 30%, 70%, and 90%, respectively. The survive rates of transfection group were highest of the three group. (2) According to the RAI score criterion, control group displayed severe AR. Intervention group displayed indeterminate AR, while transfection group showed no evidence of AR. (3) Plasma levels of ALT in control group, intervention group and transfection group were 963.43±64.21U/L, 634.73±43.28U/L and 198.23±13.82, respectively. The levels of AST were 742.46±52.71U/L, 438.36±45.34U/L and 115.79±21.23U/L, while levels of TBIL were 94.64±14.35μmol/L, 55.42±15.45μmol/L, 15.34±0.56μmol/L. The ALT, AST and TBIL levels in intervention group were lower than that in control group(P<0.05). But they were lowest in transfection group compared with intervention group and control group(P<0.05).(4)The mRNA levels of HDAC11 and IL-10 in transplanted liver were 0.91±0.22, 0.52±0.13, 0.24±0.06 and 0.29±0.04, 0.58±0.17, 1.17±0.36, while the protein levels were 1.73±0.21, 0.75±0.12, 0.42±0.06 and 0.49±0.04, 1.02±0.16, 2.45±0.28 in control group, intervention group and transfection group, respectively. The expression of HDAC11 in intervention group was lower than that in control group(P<0.05). But they were lowest in transfection group compared with intervention group and control group(P<0.05). The IL-10 expression was opposite(P<0.05). Serum IL-2 and IFN-γlevels were 154.67±14.66, 62.83±9.58, 28.49±3.97 and 93.78±11.62, 54.23±8.58, 20.65±3.45 in control group, intervention group and transfection group, respectively. However, the level of IL-10 in serum was 12.33±1.58, 34.48±4.10 and 67.50±9.39. These suggest that IL-2 and IFN-γlevels were lower in intervention group compared with control group(P<0.05). But they were lowest in transfection group compared with intervention group and control group(P<0.05). The IL-10 level was opposite(P<0.05)Conclusion: (1) The inhibition of HDAC11 can promote IL-10 expression in transplanted liver in rats. (2)The negative regulation of HDAC11 to IL-10 contributes to the induction and maintainance of immune tolerance. (3) Induction of immune tolerance are superior to the use of immunosuppressant FK506.