Heme oxygenase-1 prevents non-alcoholic steatohepatitis through suppressing hepatocyte apoptosis in mice.
OBJECTIVE
Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme catabolism, has been reported to have potential antioxidant properties. However, the role of HO-1 on hepatocyte apoptosis remains unclear. We aim to elucidate the effects of HO-1 on oxidative stress related hepatocellular apoptosis in nutritional steatohepatitis in mice.


METHODS
C57BL/6J mice were fed with methionine-choline deficient (MCD) diet for four weeks to induce hepatic steatohepatitis. HO-1 chemical inducer (hemin), HO-1 chemical inhibitor zinc protoporphyrin IX (ZnPP-IX) and/or adenovirus carrying HO-1 gene (Ad-HO-1) were administered to mice, respectively. Hepatocyte apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, the mRNA and protein expression of apoptosis related genes were assayed by quantitative real-time PCR and Western blot.


RESULTS
Hepatocyte signs of oxidative related apoptotic injury were presented in mice fed with MCD diet for 4 weeks. Induction of HO-1 by hemin or Ad-HO-1 significantly attenuated the severity of liver histology, which was associated with decreased hepatic lipid peroxidation content, reduced number of apoptotic cells by TUNEL staining, down-regulated expression of pro-apoptosis related genes including Fas/FasL, Bax, caspase-3 and caspase-9, reduced expression of cytochrome p4502E1 (CYP2E1), inhibited cytochrome c (Cyt-c) release, and up-regulated expression of anti-apoptosis gene Bcl-2. Whereas, inhibition of HO-1 by ZnPP-IX caused oxidative stress related hepatic injury, which concomitant with increased number of TUNEL positive cells and up-regulated expression of pro-apoptosis related genes.


CONCLUSIONS
The present study provided evidences for the protective role of HO-1 in preventing nutritional steatohepatitis through suppressing hepatocyte apoptosis in mice.
Nan
YueMin
Y
Department of Traditional and Western Medical Hepatology, Third Hospital of Hebei Medical University, Shijiazhuang, PR China. nanyuemin@163.com
Wang
RongQi
R
Zhao
SuXian
S
Han
Fang
F
Wu
Wen Juan
WJ
Kong
LingBo
L
Fu
Na
N
Kong
Li
L
Yu
Jun
J
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D005234:Fatty Liver; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D006427:Hemin / Q000627:therapeutic use; D022781:Hepatocytes / Q000166:cytology* / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D008297:Male; D008715:Methionine / Q000172:deficiency; D051379:Mice; D008810:Mice, Inbred C57BL; D011524:Protoporphyrins / Q000627:therapeutic use*
D011524:Protoporphyrins; C017803:zinc protoporphyrin; D006427:Hemin; D008715:Methionine; D051547:Heme Oxygenase-1