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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 5, September/October 2017
298
AFRICA
Atorvastatin inhibits cholesterol-induced caspase-3
cleavage through down-regulation of p38 and
up-regulation of Bcl-2 in the rat carotid artery
Roshanak Bayatmakoo, Nadereh Rashtchizadeh, ParichehrehYaghmaei, Mehdi Farhoudi,
Pouran Karimi
Abstract
Aim:
Atherosclerotic lesions in the carotid arteries lead to a
broad range of cerebrovascular disorders such as vascular
dementia and ischaemic stroke. Recent studies have verified
the beneficial role of atorvastatin (AV) in atherosclerosis.
Despite a large body of studies, the mechanisms underlying
this effect have not been completely explained. In this study,
several experiments were performed on atherosclerotic rat
models to investigate the anti-inflammatory and anti-apop-
totic effect of AV in the carotid artery.
Methods:
In this experimental study, 40 male Wistar rats
(250
±
25 g) were randomly divided into four groups: rats
on a normal diet (ND;
n
=
10); a high-cholesterol diet
(HD;
n
=
10); a high-cholesterol diet plus AV (HD
+
AV;
n
=
10); and the AV control group (AV;
n
=
10). Cleavage of
caspase-3 protein, expression of B-cell lymphoma 2 (Bcl-2)
as well as phosphorylation of p38 mitogen-activated protein
kinase (MAPK) were determined by immunoblotting assay
in the carotid artery homogenate. Plasma atherogenic indices,
including total cholesterol (TC), high-density lipoprotein
cholesterol (HDL-C) and low-density lipoprotein cholesterol
(LDL-C) were measured by colorimetric assay at the end of
the experiment. Plasma levels of oxidised LDL (oxLDL) were
measured by sandwich enzyme-linked immunosorbent assay
(ELISA).
Results:
After eight weeks of feeding with a high-cholesterol
diet, an elevated level of oxLDL was observed in the plasma
in the HD group compared with the ND group [214.42
±
17.46
vs 69.13
±
9.92 mg/dl (5.55
±
0.45 vs 1.78
±
0.26 mmol/l);
p
<
0.01]. AV administration significantly reduced oxLDL levels
in the HD
+
AV compared to the HD group [126.52
±
9.46 vs
214.42
±
17.46 mg/dl (3.28
±
0.25 vs 5.55
±
0.45 mmol/l);
p
<
0.01]. Results also showed that compared with the HC group,
the HC
+
AV group had lower levels of p38 phosphorylation
(
p
<
0.05) and higher levels of Bcl-2 expression (
p
<
0.05).
Lower levels of cleaved caspase-3 were observed in the HC
+
AV group in comparison with the HC group (
p
<
0.05).
Conclusions:
The resultant data suggest that the anti-apoptot-
ic effect of AV could be partially mediated by the pro-inflam-
matory protein p38 MAPK and the anti-apoptotic protein
Bcl-2 in the rat carotid artery. Atorvastatin can therefore be
considered a target drug in the prevention or development of
atherosclerotic events.
Keywords:
atherosclerosis, Bcl-2 protein, cholesterol, caspase-3,
p38 mitogen-activated protein kinase
Submitted 28/5/16, accepted 12/1/17
Published online 10/5/17
Cardiovasc J Afr
2017;
28
: 298–303
www.cvja.co.zaDOI: 10.5830/CVJA-2017-005
Atherosclerosis is a chronic inflammatory disease involving
multiple pathways. It is characterised by atheromatous plaque
consisting of a lipid-core lesion located in the sub-intima of
the bifurcation of large and medium-sized arteries, such as the
carotid and aorta.
1,2
Accumulation of low-density lipoproteins
(LDLs) and their oxidised form (oxLDLs), as major carriers of
cholesterol, initiate atherogenic events that are followed by the
recruitment of inflammatory blood cells.
1
The results of
in vitro
studies have revealed that oxidised LDL
causes injury to the endothelial cells (EC),
3
the mechanism of
which is unknown, resulting in necrosis or apoptosis.
4
Apoptosis
refers to the morphological changes exhibited by ‘actively’ dying
cells, including DNA fragmentation, chromatin condensation,
membrane blebbing and cell shrinkage,
5
whereas necrosis is
rupture of the plasma membrane and cell lysis following
cellular swelling.
4
The signal transduction leading to apoptosis
is characterised by a complex array of biochemical pathways,
including inflammation, mitochondrial dysfunction and cell
proliferation.
6
Moreover, triggering of mitogen-activated protein kinase
(MAPK), which is a classic inflammatory cascade, is required
for oxLDL-attributed induction of apoptosis.
7
Dysregulation
of the MAPK pathway during atherosclerosis leads to modified
gene expression, which facilitates disease processes.
3
Three
major members of the MAPK family that are entirely involved
in atherogenic events are extracellular signal-regulated kinase
(ERK), c-Jun kinase (JNK) and p38 MAPK. Among them,
p38, a well-known stress kinase, controls foam cell formation
and programmed cell death in macrophages, and facilitates
the expression of chemokines and adhesion molecules in the
endothelial cells.
3
Department of Biology, Science and Research Branch,
Islamic Azad University, Tehran, Iran
Roshanak Bayatmakoo, PhD
ParichehrehYaghmaei, PhD
Biotechnology Research Centre, Tabriz University of
Medical Sciences, Tabriz, Iran
Nadereh Rashtchizadeh, PhD,
rashtchizadeh@rocketmail.comNeurosciences Research Centre (NSRC), Tabriz University
of Medical Sciences, Tabriz, Iran
Mehdi Farhoudi, MD
Pouran Karimi, PhD