EFFECT OF NF κB ON iNOS SYNTHESIS IN RABBIT PULMONARY SMOOTH MUSCLE INDUCED BY ENDOTOXIN
Wan Mei, Ling Yiling, Wang Dianhua (Department of Pathophysiology, Hebei Medical University, Shijiazhuang 050017)
Aim and Methods: To study whether the defects in contractility could be induced in endothelium denuded pulmonary artery ring by exposure to lipopolysaccharides, (LPS) in vitro, and whether contractile response was altered after the action of aminoguanidine (AG) an inhibitor of inducible nitric oxide (NO) synthesis as well as pyrrolidine dithiocarbamate (PDTC), an antagonist of NF κB. Results: The contractions of vessels to phenylephrine (PE) were suppressed ( P 0.01) by incubation with LPS for 16h in comparison with control. The addition of AG during the incubation improved tissue reactivity to PE. The sensitivity of vessels to PE improved markedly after pre incubated with PDTC for 1.5 h before the incubation with LPS. After treatment with N ω nitro l arginine (L NNA) an inhibitor of NO synthesis, the reactivity of rings to PE improved significantly in LPS incubated group, while the change was not significant in PDTC pre incubated group. Conclusion: iNOS was induced in vascular smooth muscle after exposure to LPS, while NF κB acted as a signal transduct substance in the induction of iNOS in pulmonary smooth muscle.