DTNB improves cardiovascular dysfunction and enhance survival of septic rats
Patrícia de Oliveira Benedet, Ana Maria Favero, Karin Scheschowitsch, Muryel
Carvalho Gonçalves, Jamil Assreuy
Department of Pharmacology, Universidade Federal de Santa Catarina-UFSCFlorianópolis (SC), Brazil.
Objectives Nitrosative stress has been described as an important factor in
cardiovascular dysfunction of sepsis. One of the mechanisms whereby NO exerts
some of its effects is the reaction with thiol groups of cysteine residues (sulphydryls) in
a process called S-nitrosylation, producing S-nitrosothiols. It have been reported that
the increased in the level of nitrosylated proteins can contribute to pathogenesis of
septic shock. The aim of the present study is to show that DTNB [5,5'-dithio-bis-(2nitrobenzoic acid) an oxidizing agent of sulfhydryl has an important impact in
homeostasis and mortality in sepsis.
Methods Wistar female rats were anesthetized and submitted to cecal ligation and
puncture (CLP) procedure. Twelve hours after surgery, animals received DTNB or
vehicle. Twenty-four hours after CLP, S-nitrosylated proteins levels in aorta,
concentration-response curves to phenylephrine in aorta rings, survival, and
biochemical and haemodynamic parameters were evaluated. All procedures have been
approved by our institutional Animal Ethics Committee (protocol number PP
00790/CEUA/UFSC).
Results Sepsis significantly increased plasma levels of NO metabolites, GOT (glutamic
oxaloacetic transaminase), GPT (glutamic pyruvic transaminase) and lactate levels
besides inducing a pronounced hypotension, hyporesponsiveness to phenylephrine
and increased levels of nitrosylated proteins in aorta. DTNB injected 12 h after sepsis
induction reduced levels of GOT, GPT, lactate along with a substantial reduction of
nitrosylated proteins in aorta. DTNB attenuated the hypotension and, more importantly,
the reactivity to phenylephrine was completely normalized. Finally, DTNB reduced the
mortality of septic rats by 40%.
Conclusions Our results show that S-nitrosylation of protein contributes to sepsisinduced vascular dysfunction. The key finding however, is to show that DTNB-induced
protein denitrosylation restored hemodynamic functions, decreased organ damage and
enhanced survival in septic rats acting as a therapeutic agent after sepsis onset.
Financial support: CNPq, CAPES, FAPESC and FINEP.