Tribulosin protects rat hearts from ischemia/reperfusion injury.
OBJECTIVE
To investigate the protective effect of tribulosin, a monomer of the gross saponins from Tribulus terrestris, against cardiac ischemia/reperfusion injury and the underlying mechanism in rats.


METHODS
Isolated rat hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion using Langendorff's technique. The hearts were assigned to seven groups: control, ischemia/reperfusion (I/R), treatment with gross saponins from Tribulus terrestris (GSTT) 100 mg/L, treatment with tribulosin (100, 10, and 1 nmol/L) and treatment with a PKC inhibitor (chelerythrine) (1 micromol/L). Infarct size was assessed by triphenyltetrazolium chloride staining. Malondialdehyde (MDA), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) contents as well as superoxide dismutase (SOD) and creatine kinase (CK) activities were determined after the treatment. Histopathological changes in the myocardium were observed using hematoxylin-eosin (H&E) staining. Apoptosis was detected with terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) assay. Bcl-2, Bax, caspase-3, and PKCepsilon protein expression were examined using Western blotting.


RESULTS
Tribulosin treatment significantly reduced MDA, AST, CK and LDH contents, and increased the activity of SOD. The infarct size of I/R group was 40.21% of the total area. GSTT and various concentrations of tribulosin treatment decreased the infarct size to 24.33%, 20.24%, 23.19%, and 30.32% (P<0.01). Tribulosin treatment reduced the myocardial apoptosis rate in a concentration-dependent manner. Bcl-2 and PKCepsilon protein expression was increased after tribulosin preconditioning, whereas Bax and caspase-3 expression was decreased. In the chelerythrine group, Bcl-2 and PKCepsilon expression was decreased, whereas Bax and caspase-3 expression was increased.


CONCLUSIONS
Tribulosin protects myocardium against ischemia/reperfusion injury through PKCepsilon activation.
Zhang
Shuang
S
Department of Pharmacology, Norman Bethune College of Medicine, Jilin University, Changchun, China.
Li
Hong
H
Yang
Shi-jie
SJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D053148:Caspase 3 / Q000378:metabolism; D004789:Enzyme Activation; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D017202:Myocardial Ischemia / Q000150:complications* / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy; D051744:Protein Kinase C-epsilon / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012855:Sitosterols / Q000627:therapeutic use*; D032444:Tribulus; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C494828:Bax protein, rat; D002316:Cardiotonic Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D012855:Sitosterols; D051028:bcl-2-Associated X Protein; C472188:tribulosin; D051744:Protein Kinase C-epsilon; D053148:Caspase 3
Chem Biodivers. 2009 Aug;6(8):1170-7
19697334
Am J Physiol Heart Circ Physiol. 2000 Oct;279(4):H1679-89
11009455
Circ Res. 2004 Jan 9;94(1):7-16
14715531
Cell Signal. 2007 Aug;19(8):1633-42
17537614
Pharmacol Res. 2007 Jun;55(6):523-36
17576073
Exp Biol Med (Maywood). 2006 Apr;231(4):463-72
16565442
Yao Xue Xue Bao. 2009 Feb;44(2):134-9
19408681
J Pharmacol Exp Ther. 2006 Jul;318(1):186-94
16551837
Mol Biol Rep. 2009 Feb;36(2):365-70
18049909
Zhong Xi Yi Jie He Xue Bao. 2008 Jan;6(1):45-50
18184546
J Clin Invest. 2002 Feb;109(4):499-507
11854322
Free Radic Biol Med. 2009 Jun 15;46(12):1589-97
19303434
Heart. 2007 Aug;93(8):903-7
16670100
Am J Physiol Heart Circ Physiol. 2006 Aug;291(2):H854-60
16501016
Am J Physiol Heart Circ Physiol. 2006 Oct;291(4):H1893-9
16714357
J Biol Chem. 2007 Nov 2;282(44):32288-97
17785460
Biophys J. 2001 May;80(5):2140-51
11325717
J Asian Nat Prod Res. 2008 Jan-Feb;10(1-2):39-48
18058379
Am J Physiol. 1999 May;276(5):H1468-81
10330229
J Clin Invest. 1998 May 15;101(10):2182-98
9593774
FASEB J. 2005 May;19(7):831-3
15764590
Am J Physiol Heart Circ Physiol. 2007 Apr;292(4):H1995-2003
17172266