The Effect of Post-Treatment N-Acetylcysteine in LPS-Induced Acute Lung Injury of Rats / 결핵및호흡기질환

ABSTRACT

BACKGROUND: Oxidation plays an important role in acute lung injury. This study was conducted in order to elucidate the effect of repetitive post-treatment of N-acetylcysteine (NAC) in lipopolysaccaride (LPS)-induced acute lung injury (ALI) of rats. METHODS: Six-week-old male Sprague-Dawley rats were divided into 4 groups. LPS (Escherichia coli 5 mg/kg) was administered intravenously via the tail vein. NAC (20 mg/kg) was injected intraperitoneally 3, 6, and 12 hours after LPS injection. Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained to evaluate the ALI at 24 hours after LPS injection. The concentration of tumor necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta) were measured in BALF. Nuclear factor kappaB (NF-kappaB), lipid peroxidation (LPO), and myeloperoxidase (MPO) were measured using lung tissues. Micro-computed tomography (micro-CT) images were examined in each group at 72 hours apart from the main experiments in order to observe the delayed effects of NAC. RESULTS: TNF-alpha and IL-1beta concentration in BALF were not different between LPS and NAC treatment groups. The concentration of LPO in NAC treatment group was significantly lower than that of LPS group (5.5+/-2.8 nmol/mL vs. 16.5+/-1.6 nmol/mL) (p=0.001). The activity of MPO in NAC treatment group was significantly lower than that of LPS group (6.4+/-1.8 unit/g vs. 11.2+/-6.3 unit/g, tissue) (p<0.048). The concentration of NF-kappaB in NAC treatment group was significantly lower than that of LPS group (0.3+/-0.1 ng/microL vs. 0.4+/-0.2 ng/microL) (p=0.0001). Micro-CT showed less extent of lung injury in NAC treatment than LPS group. CONCLUSION: After induction of ALI with lipopolysaccharide, the therapeutic administration of NAC partially attenuated the extent of ALI through the inhibition of NF-kappaB activation.