[Farnesoid-X-receptor blockade reduces myocardial reperfusion injury in cholesterol-fed apolipoprotein E knockout mice].
OBJECTIVE
To investigate the effect of farnesoid-X-receptor (FXR) antagonist Z-guggulsterone in an in vivo high-fat fed apolipoprotein E knockout (ApoE(-/-)) mice model of myocardial ischemia/reperfusion (I/R).


METHODS
Male ApoE(-/-) mice were randomly divided into three groups: standard ApoE(-/-) group (fed with standard mouse diet for 12 weeks before myocardial I/R procedure, n = 18), high-fat ApoE(-/-) group (fed with high-fat mouse diet for 12 weeks before myocardial I/R procedure, n = 22), and high-fat ApoE(-/-) + FXR antagonist group(fed with high-fat mouse diet for 12 weeks and received FXR antagonist Z-Guggulsterone 30 minutes before myocardial I/R procedure, n = 17). The expression of FXR was detected by real-time quantitative-PCR. Myocardial infarct size was determined by Evans blue/TTC double staining methods. Myocardial apoptosis was determined by in situ TUNEL technique. Markers of the mitochondrial-mediated apoptotic pathway (cytochrome c release, caspase-9 activity, and BAX and BCL-2 levels), endoplasmic reticulum stress apoptotic pathway (caspase-12 activity and CHOP level), and death receptor apoptotic pathway (caspase-8 activity, and Fas and FasL levels) were also measured.


RESULTS
FXR expression (3.7-fold higher, P < 0.01), myocardial infarct size [(62.1 ± 7.0)% vs. (33.8 ± 5.8)%, P < 0.01] and myocardial apoptosis index[ (36.8 ± 5.7)% vs. (17.2 ± 3.8)%, P < 0.01]were all significantly higher in high-fat ApoE(-/-) group than those in standard ApoE(-/-) group. Compared with high-fat ApoE(-/-) group, myocardial infarct size [(24.4 ± 4.7)% vs. (62.1 ± 7.0)%, P < 0.01] and myocardial apoptosis index [(13.8 ± 2.7)% vs. (36.8 ± 5.7)%, P < 0.01] were significantly reduced in high-fat ApoE(-/-) + FXR antagonist group. Moreover, levels of mitochondrial-mediated apoptotic pathway markers (cytochrome c release, caspase-9 activity, and BAX/BCL-2 levels) and endoplasmic reticulum stress apoptotic pathway markers (caspase-12 activity and CHOP level) were significantly lower in high-fat ApoE(-/-) + FXR antagonist group than those in high-fat ApoE(-/-) group (all P < 0.01). Levels of death receptor apoptotic pathway markers (caspase-8 activity, and Fas and FasL levels) were similar between high-fat ApoE(-/-) group and high-fat ApoE(-/-) + FXR antagonist group.


CONCLUSIONS
FXR antagonist alleviates myocardial reperfusion injury in cholesterol-fed ApoE(-/-) mice via inhibition of the mitochondrial-mediated and endoplasmic-reticulum stress pathway.
Department of Cardiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, China.
Huan
H
Tong
Pei-ren
PR
Shan
Yi-chao
YC
Zhao
An-cai
AC
Yuan
Qing
Q
He
Tian-bao
TB
Yao
Xiao-ying
XY
Ying
Jun
J
Pu
Ben
B
He
D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics*; D017209:Apoptosis / Q000187:drug effects; D053453:Caspase 9 / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D045304:Cytochromes c / Q000378:metabolism; D004195:Disease Models, Animal; D059865:Endoplasmic Reticulum Stress; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D011282:Pregnenediones / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D000099150:Receptor, Farnesoid X-Activated
D001057:Apolipoproteins E; D053453:Caspase 9; D002791:Cholesterol, Dietary; D045304:Cytochromes c; D011282:Pregnenediones; D019253:Proto-Oncogene Proteins c-bcl-2; D018160:Receptors, Cytoplasmic and Nuclear; D051028:bcl-2-Associated X Protein; D000099150:Receptor, Farnesoid X-Activated; C494827:Bax protein, mouse; C052617:Bcl2 protein, mouse; C023617:pregna-4,17-diene-3,16-dione; C506434:Casp9 protein, mouse