Inhibitory effect of methylene chloride-induced on cardiac allograft rejection in a murine heart transplantation model / 中华器官移植杂志

ABSTRACT

Objective To investigate the role of induction of carbon monoxide (CO) with methylene chloride (MC) in recipients in ameliorating allograft rejection and prolonging allograft survival and to explore the possible mechanisms in a murine heart transplantation model.Methods Inbred male C57BL/6 mice were used as donors and inbred male Balb/c mice as recipients respectively to establish cervical heterotopic heart transplantation model.The experiments were divided into 3 groups.Recipients were treated with MC (100 mg/kg,per os) day 1 prior to transplantation to day 6 posttransplantation (group MC1w) or to day 13 posttransplantation (group MC2w),or treated with isovolumic olive oil day 1 prior to transplantation to cardiac arrest of allograft (group Tx).The serum TNF-α and IL-10 proteins,TNF-α and IL-10 mRNA,and Foxp3 mRNA and protein in cardiac grafts were measured respectively.The intercellular adhesion molecule-1 (ICAM-1) and Caspase-3 protein in cardiac grafts,and the histopathologic changes of cardiac grafts were also observed.Results Serum COHb levels in untreated mice were (0.85 ± 0.28)％.After MC application,serum COHb peaked within 3 h in recipients (5.24 ± 0,45)％ (P＜0.01 ).The median survival time of cardiac grafts in group MC1w(12.1 days) and group MC2w( 19.4 days) was longer than that in group Tx (6.3 days) (P ＜0.01). As compared with group Tx,induction of CO in group MC1w and group MC2w down-regulated significantly the levels of serum TNF-α (P＜0.01 ) and TNF-α mRNA (P＜0.01) of cardiac grafts and spleen in recipient mice,inhibited the protein expression of ICAM-1 (P＜0.01) and Caspase-3 (P＜0.01) of cardiac grafts,and inhibited,especially in group MC2w,the proliferation of lymphocytes and monocytes infiltration in cardiac grafts.There was no significant difference in serum IL-10 and Foxp3 mRNA and protein in cardiac grafts and spleen of recipients among the groups (P＞0.05).Conclusion Induction of CM in recipients could relieve cardiac allograft rejection and prolong cardiac allograft survival via its anti-inflammation and anti-apoptotic effects,not via up-regulation of Foxp3 in recipient mice.