[Protective effect of N-acetylcysteine against lipopolysaccharide injury in hepatocytes of neonatal mice].
OBJECTIVE
N-Acetylcysteine (NAC) is a sulfhydryl donor molecule with antioxidant and antiinflammatory effects. A major role has been described for inducible nitric oxide (NO) synthase in several inflammatory liver diseases. NAC attenuates NO generation following lipopolysaccharide injection in rats. The purpose of this study was to investigate the effect of NAC against lipopolysaccharide injury in hepatocytes of neonatal mice and the molecular mechanisms by which NAC influences inflammatory responses of the hepatocytes.


METHODS
The liver of neonatal mouse was digested by collagenase to dissociate the hepatocytes. The hepatocytes were cultured and isolated. After 7 days of culture the normal hepatocytes were divided into two groups: LPS group and NAC group. In LPS group, 10 microg/ml LPS was added into the culture medium. In NAC group, 5 mmol/L NAC was added into the culture medium firstly, 10 microg/ml LPS was added after 1 h of culture. There were 12 mice in each group. The cell supernatants and the hepatocytes were collected at 0, 6 and 12 hours after adding LPS. The cell supernatants were taken to measure the alanine aminotransferase (ALT) level and nitric oxide (NO) production by the biochemical methods. The cells were taken to analyze the gene expression of induced nitric oxide synthase (iNOS) by the RT-PCR.


RESULTS
In LPS group, the levels of ALT, NO and iNOS mRNA increased significantly at the time points 6 h and 12 h compared with the time point 0, (P < 0.01). Compared with the LPS group, the levels of ALT, NO and iNOS mRNA of NAC group were lower at the time points 6 h and 12 h (P < 0.01).


CONCLUSIONS
NAC may play a protective role in the hepatocytes injury caused by LPS in the neonatal mice. The protective mechanism works partially through the inhibition of iNOS activation by LPS.
Wang
Lin
L
Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Xu
Jian-bo
JB
Tian
Yuan
Y
Wu
He-shui
HS
Liu
Ya-lan
YL
D000111:Acetylcysteine / Q000494:pharmacology*; D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D022781:Hepatocytes / Q000187:drug effects*; D008070:Lipopolysaccharides; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D000410:Alanine Transaminase; D000111:Acetylcysteine