Effect Of Genistein Combined With Cyclosporine A On CXCR3 In Acute Rejection Of Cardiac Allograft

Background With the development of surgical techniques, the use of immunosuppressants and the improvement of holistic healthcare, the heart transplant technology has obtained relatively rapid growth, and the survival rates of heart transplant recipients have been remarkably improved. However recipients still face the risks of hyperacute rejection, acute rejection and chronic rejection, which directly affect the survival and prognosis of patients. And the diagnosis and prevention of acute rejection after heart transplantation are particularly important. Numerous studies have shown that the interactions between chemokine receptors and chemokines play important roles in the activation of immune cells and the recruitment of T lymphocytes into the tissue of transplanted organs, and they are hyperactive in acute rejection of allografts. So the antagonists of chemokine receptors may suppress the immune rejection in allografts. CXC chemokine receptor-3 (CXCR3) belongs to G-protein coupled receptors superfamily, and the interactions between CXCR3 and its ligands can result in apoptosis and necrosis of transplantation cells by activation of immune cells into allograft tissues. Some studies have shown that the activation of protein tyrosine kinase (PTK) is the key factor of interactions and cascade reactions between CXCR3 and its ligands. And Genistein have an anti-PTK effect.Objective To investigate the relationship between CXCR3 and acute rejection and the effect of Genistein combined with cyclosporine A on CXCR3 in acute rejection of cardiac allograft by making acute rejection models and immune tolerance models in rats.Methods Heterotopic cervical heart transplantation was performed from Wistar rats to SD rats by using cuff-technique. The SD rat recipients were randomly divided into 3 groups, with 12 in each group. No treatment was adopted in the acute rejection (AR) group. Rats in the cyclosporine A(CsA) group were treated with 10mg/kg/d cyclosporine A after transplantion. Rats in CsA+Genistein(C+G) group were treated with 10mg/kg/d Genistein combined with 10mg/kg/d cyclosporine A after transplantion. The survival conditions of cardiac allografts were judged by touching the right cervical of rat recipients. All the cardiac allografts were harvested at 7th day, and made into tissue slices. The HE-staining was used to observe the pathology changes of the allograft myocardia. And the expression of CXCR3 was detected with immunehistochemistry and western blotting. Image analysis software were used to semiquantitative analysis the degrees of CXCR3 expressions.Results The survival conditions of cardiac allografts in the CsA group and C+G group were obviously better than the AR group. The HE-staining results show that the degrees of inflammatory cells infiltration and myocardial necrosis in AR group were more serious than the CsA group and C+G group. The IOD of cardiac allografts in AR group, CsA group and C+G group were (1.05±0.20)×105, (0.53±0.16)×105 and (0.24±0.08)×105. The expression of CXCR3 in CsA group was much lower than the AR group and the expression of CXCR3 in C+G group were much lower than the other two groups (P<0.05). The trend of expression of CXCR3 in western blotting is consistent with result of immunehistochemistry. The expression of CXCR3 in C+G group were much lower than the other two groups (P<0.05).Conclusions The expression level of CXCR3 is closely related to the severity of cardiac graft acute rejection. Genistein combined with cyclosporine A can significantly relieve rejection of cardiac allograft by inhibiting the expression of CXCR3.