Participação do L-NAME, da L-arginina e da N-acetilcisteína no enfisema pulmonar induzido por fumaça de cigarro em camundongos / The lung remodeling in mouse emphysema is independent of nitric oxide modulation

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

Nitric oxide (NO) represents one of the most important intra and extracellular mediators/messengers. It takes part in both biologic and pathologic processes. This study aimed to verify NO role in pulmonary emphysema induced by cigarette smoke (CS) in mice. So L-NAME (LN) (a NOinhibitor) and L-arginine (LA) (a substract for NO formation) were analyzed and compared to N-acetylcysteine (NAC) (which is used in COPD treatment). A total of 65 C57BL/6 male mice were used. Fifty of them were divided in control, cigarette smoke (CS), cigarette smoke + L-NAME (CS+LN), cigarette smoke + L-arginin (CS+LA) and cigarette smoke + N-acetylcysteine (CS+NAC) groups (n = 10, each group). Forty animals were exposed to 12 commercial cigarettes 3 times a day for sixty days. Control and CS groups were submitted to orogastric gavages with saline. FC+LN, FC+LA, FC+NAC groups received daily gavages with L-NAME (60 mg/kg), L-arginine (120 mg/kg) and NAC (200 mg/kg) respectively. Fifteen animals (n=5, each group) were exposed to ambient air and treated with L-NAME, L-arginine and NAC alone. Cell profile of bronchoalveolar lavage was analyzed and the right lung was removed in order to perform histological analysis of air space enlargement. This was done measuring median alveolar diameter (Lm) and total alveolar septal volume (Sv) of alveolar septa. Left lungs were removed and homogenized to perform enzymatic activity (SOD, CAT and MPO) and glutathione ratio analysis (GSH/GSSG). Besides it, nitrite values and the expression of 4-HNE, MMP-12, NE, TIMP-1 and TIMP2 were also performed. L-arginine administration favored NOproduction and release, while L-NAME use inhibited. Briefly, we suggest L-NAME action to be directed to extracellular matrix (via proteinase-antiproteinase), while L-arginine action is directed to oxidants, similar to NAC. Our results showed that NAC acts raising glutathione levels which interfere directly with oxidants (via oxidant-antioxidant) while L-arginine acts raising oxidative burden at the same time it raises oxidants time of action. This also increases inflammatory cell numbers, but decreases their time of action, allowing a longer remodeling period. In conclusion, NOand both effects were efficient in lung protection/remodeling, although this remodeling was not as effective as when NAC was administrated.

ASSUNTO(S)

Óxido nítrico fumaça de cigarro inflamação estresse oxidativo camundongos fisiologia da digestao nitric oxide cigarette smoke inflammation oxidative stress mice

ACESSO AO ARTIGO

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