Inhibitory effects ofleflunomide and cyclosporine on NF- κ B signal pathway in mouse torat cardiac xenograft

Abstract

：Objective Toinvestigated the effects of leflunomide (Lef) in combination with cyclosporine (CsA) onIKKcomα/β,NF-kB P65, IkBα, ICAM-1 and NF-kB DNA binding activity in NF-kB signal pathway inmouse to rat cardiac xenografts. Methods NIH mice and Wistar rats served as donors andrecipients respectively. Mouse to rat heterotopic heart transp lantation was performed (inthe neck). The experiments were divided into 4 groups: CsA was injected imraperitoneallyafter operation in the CsA group; Lef was given in the Lef group by gastric tube afteroperation; CsA com-bined with Lef was administered after operation in CsA+Lef group; Inthe control group, the recipi-ents didn't recei veany medicine treatment. After operation,the survival of the transplanted heart was observed. The histophathologic examination wasdone in the transplanted heart. The expression of IKKα/β, NF-kB P65, IkBα and ICAM-1 and NF-kB DNA binding activity in cardiac xenografttissues were determined by immunohistochemistry and Western blot as well aselectrophoretic mobility shift assay (EMSA) in each group. Results The survival time ofthe cardiac xenografts in control group,CsA group, Lef group and CsA+Lef group was (2.17±0.41),(2.50±1.05), (4.17±1.33) and (6.50±2.56) days, respectively, significantly longer inCsA + Lef group than in other three groups(P<0.05), and significantly longer in Lefgroup than in control group (P<0.05). The expression ofIKKα/β (IOD) in cardiac xenografttissues in control group, CsA group, Lef group and CsA+Lef group was (137.1±4.0), (149.7±6.5),(111.6±14.6) and (81.4±15. 9), the expression ofNF-kB P65 (IOD) was (261.3±31.6),(263.1±28.8), (173.5±5.9) and (67.8+3.8), theexpression of IkBa (IOD) was (88.6±6.7),(80.4±3.5), (64.8±8.9) and (37.3±4.4), theexpression of ICAMol (IOD) was (155.4±5.3),( 150.7+5.1), ( 104.7±6.2) and (29.2±2.8),and NF-gB DNA binding activity (IOD) was(234.3±8.7), (227.5±14.8), (110.9±12.5) and(43.6±7.4), respectively. The IODs in CsA +Lef group were markedly lower than in the other threegroups (P<0.05), and those in Lefgroup was obviously lower than in control group (P<0.05).Conclusion The combined use ofLef and CsA can significantly suppress the expression of IKKα/αβ,NF-kB P65, IkBα, ICAM-1 and NF-kB DNA bindingactivity, which may obviously prolong thesurvival time of mouse to rat cardiac xenografts. Key words: Transplantation, heterologous; Heart transplantation; Immunosuppressive agents; NF-kappa B