[The role of miRNA-122 expression during the acute liver failure in mice induced by D-GalN/LPS].
OBJECTIVE
To investigate the expression of miR-122 and its relationship with progression and development of acute liver failure in mice induced by D-GalN/LPS, and to explore new biomarker(s) for early diagnosis of acute liver failure.


METHODS
BALB/C mice were randomly divided into four groups: the mice were given D-GalN (900 mg/kg body weight) and LPS (10 micog/kg body weight) intraperitoneally (i.p.) to construct the acute liver model; whereas the control groups were given D-GalN (900 mg/kg), LPS (10 microg/kg) and normal saline respectively. All biochemical and histological indexes were determined at 0, 1, 3, 5, 7 and 9 h respectively after administration. Real-time RT-PCR were used to detect the expression of miR-122 and pro-inflammatory cytokines, furthermore, the expression of miR-122 was verified by LNA (lock nucleic acid)-Northern-blot. ALT and AST levels were tested by biochemistry analyzer. Serum pro-inflammatory cytokine levels were tested by ELISA.


RESULTS
The mortality rate was about 80% at 24h after D-GalN/LPS treatment, but no mortality was observed in the other three control groups. Liver special miRNA miR-122 was highly expressed in liver tissue of normal mice (ct is approximately equal to 14), it was up-regulated significantly (P = 0.013) at first hour after treatment then down-regulated according to the development of acute liver failure, the change was more obvious at 9 h (ct is approximately equal to 15, P = 0.002). ALT and AST levels increased obviously at 3h after treatment and reached peak at 7 hours then they were declined sharply. It was found that the expression of miR-122 was faster and more durable than ALT. Pro-inflammatory cytokines related to acute liver failure including TNFa and IL-6 were all up-regulated in serum as well as liver tissue (P less than 0.05). Correlation analysis showed that miR-122 had a negative correlation with ALT (correlation coefficients -0.505) and positive correlations with TNFa and IL-6 (correlation coefficients were 0.493 and 0.674 respectively).


CONCLUSIONS
Liver-specific miR-122 supposed be a new marker molecule for early diagnosis of liver cells injury in the acute liver failure.
An
Fang-mei
FM
Department of Infectious Diseases, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Yu
Dong-shan
DS
Xie
Qing
Q
Gong
Bang-dong
BD
Wang
Hui
H
Guo
Qing
Q
Yu
Hong
H
D000818:Animals; D005688:Galactosamine / Q000009:adverse effects; D015850:Interleukin-6 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000009:adverse effects; D017114:Liver Failure, Acute / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015850:Interleukin-6; D008070:Lipopolysaccharides; D035683:MicroRNAs; C544354:Mirn122 microRNA, mouse; D014409:Tumor Necrosis Factor-alpha; D005688:Galactosamine