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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 5, September/October 2017
AFRICA
301
but AV attenuated the cleaved caspase-3 level in the carotid tissue
of hypercholesterolaemic rats (Fig. 3B). Furthermore, to determine
whether bcl-2 protein interfered in the cholesterol-induced cleavage
of caspase-3, the protein expression levels of bcl-2 were evaluated
in all groups. The results showed a significant decrease in bcl-2
level in the HD versus the ND group. Moreover, AV prevented this
suppression (Fig. 3C). We then determined the phosphorylation
state of p38, a stress kinase, after AV treatment, and found that AV
significantly decreased cholesterol-induced phospho-p38 (Fig. 4).
Discussion
Dysregulation of plasma metabolites and tissue apoptosis are
common features of a wide range of degenerative disorders
such as atherosclerosis. Risk factors for atherosclerosis, such as
oxidative stress, inflammation, hypercholesterolaemia, central
obesity and abnormal levels of coagulants often co-exist.
Our experimental study explored the evidence that AV
therapy (20 mg/kg), besides its cholesterol-lowering effects,
decreased inflammatory and apoptotic events in the carotid
artery of an atherosclerotic rat model. We produced the
moderate atherosclerotic rat model with the administration of
2% cholesterol [TC
=
229.35
±
13.26 mg/dl (5.94
±
0.34 mmol/l)],
compared with the study by Samout
et al
. of 1% cholesterol [TC
=
90.71
±
3.08 mg/dl (0.25
±
0.08 mmol/l)] and that of Beason
et al
. of 4% cholesterol (TC
=
595
±
429 mg/dl (15.41
±
11.11
mmol/l).
26,27
We used this model to investigate the expression of
inflammation and apoptosis-related proteins in the carotid
tissue of hypercholesterolaemic rats after receiving AV. We did
not carry out a histopathological study on the carotid tissue,
but based on a previous study, even a 1% cholesterol-rich
diet is capable of damaging the blood vessels and initiating
atherosclerotic events.
28
Ntchapda
et al
. showed extensive
atherosclerotic plaques were created in almost the whole upper
part of the hypercholesterolaemic rat aorta, which was not the
case with the normocholesterolaemic rats.
28
In our study, cholesterol-induced hyperlipidaemia was
clearly attenuated after eight weeks of statin treatment. This
was because of the cholesterol-lowering effect of AV,
29
via
inhibition of HMG-CoA reductase, the check-point step in
cholesterol synthesis.
14
Moreover, previous studies have shown
Cleaved caspase 3
Bactin
42 kd
29 kd
17 kd
Bc12
ND
HD
HD + AV
AV
Cleaved caspase 3/Bactin
(% of control)
200
150
100
50
0
**
##
ND
HD
HD + AV
AV
Bcl-2/Bactin (% of control)
120
100
80
60
40
20
0
**
##
Fig. 3.
Down-regulation of cleaved caspase-3 and up-regula-
tion of Bcl-2 in the carotid artery of an atherosclerotic
rat model after administration of oral atorvastatin (20
mg/kg for eight weeks). A. Immunoblotting of cleaved
caspase-3, Bcl-2, and Bactin in ND, HD, HD
+
AV
and AV groups. B. Quantitation of immunoblotting of
cleaved caspase-3. C. Quantitation of immunoblotting
of Bcl-2. Values are shown as the mean
±
SD of six
animals in each group. *
p
<
0.05.
A
B
C
Phosphor-p38
40 kd
40 kd
Total p38
ND
HD
HD + AV
AV
p-p38/total p38
(% of control)
250
200
150
100
50
0
**
##
Fig. 4.
Down-regulation of phosphor-p38 MAPK in the
carotid artery of an atherosclerotic rat model after
administration of oral atorvastatin (20 mg/kg for eight
weeks). A. immunoblotting of phosphor-p38 MAPK,
and p38 MAPK in ND, HD, HD
+
AV and AV groups.
B. Quantitation of immunoblotting of phosphor-p38
MAPK. Values are shown as the mean
±
SD of six
animals in each group. *
p
<
0.05.
A
B