Redox unbalance increases Bax protein expression and cytochrome c release in Trypanosoma cruzi-infected C57BL/6 mice.

RONCO, MARIA TERESA; FRANCES, DANIEL ELEAZAR ANTONIO; QUIROGA, ARIEL DARIO; ALVAREZ, MARIA DE LUJAN; PARODY, JUAN PABLO; MONTI, JUAN ALBERTO; CARRILLO, MARIA CRISTINA; REVELLI, SILVIA; CARNOVALE, CRISTINA ESTER

Montevideo, Uruguay

Congreso; V Meeting of SFRBM - V International Conference on Peroxynitrite and Reactive Nitrogen Species; 2007

Redox unbalance increases Bax protein expression and cytochrome c release in Trypanosoma cruzi-infected C57BL/6 mice. Ronco Maria T, Franc¨¦s Daniel, Quiroga Ariel D, Alvarez M Lujan, Parody Juan P, Monti Juan, Carrillo M Cristina, Revelli Silvia, Carnovale Cristina Introduction: The protozoan parasite Trypanosoma cruzi (T. cruzi) causes a persistent, lifelong infection; wich can lead to Chagas¡¯ disease, a major health problem in Latin America. T. cruzi infected C57BL/6 mice developed a progressive fatal disease due to an unbalance in the profile of circulating cytokines. TNF¦Á and nitric oxide were increased in serum from T. cruzi infected mice (Roggero, 2002); both have been proposed as important effectors molecules in oxidative stress and apoptosis. Liver is a target of T. cruzi infection producing different cytokines and inflammation mediators. Objective: evaluate cellular redox state and proteins involved in apoptotic process in infected mice liver. Results: C57BL6/mice were infected subcutaneously with 100 viable trypomastigotes of Tulahu¨¦n strain of T. cruzi. Animals were killed 7 and 14 days post-infection. Parasite blood levels in T. cruzi-infected mice (parasite/50 fields): 7days: 1.0¡À0.2; 14 days: 63.0¡À5.0 (30-72). % oxidized glutathione (Tietze method): Control: 3.38¡À0.43; T cruzi 7d: 4.97¡À0.65; T cruzi 15d: 20.19¡À2.89*. Lipoperoxidation levels (nmol malondialdheyde/mg prot): Control: 28.44¡À3.28; T. cruzi 7d: 46.70¡À8.43; T. cruzi 15d: 56.28¡À4.18*. Expression of liver mitochondrial pro-apoptotic protein Bax (western blot, arbitrary densitometry units) were: Control: 320¡À28; T. cruzi 7d: 448¡À108; T. cruzi 15d: 5646¡À232*. Anti-apoptotic protein Bcl-xL expression (western blot, arbitrary densitometry units): Control: 465¡À66; T. cruzi 7d: 486¡À36; T. cruzi 15d: 2473¡À290*. The relative prevalence of Bax and Bcl-xL protein are critical factors influencing cell fate; they promove cell either survival or death, whose ultimate outcome largely depends on the Bax/Bcl-xL ratio (Control: 1.65¡À0.66; T. cruzi 7d: 0.99¡À0.20; T. cruzi 15d: 9.16¡À2.86*. Cytochrome c were increase in cytosol fraction (western blot, arbitrary densitometry units): Control: 52.33¡À26.42; T. cruzi 7d: 141.66¡À28.42; T. cruzi 15d: 1345.33¡À264.42*. (*p<0.05 vs Control). Conclusion: Ours results demonstrated that mice infective liver shown an increase of oxidative stress which produce augmentation of pro-apoptotic proteins and cytochrome c release, suggesting that T. cruzi infection promove apoptosis of liver cells.