ATO attenuates atherosclerotic plaque progression and
destabilisation in ApoE-/- mice
To investigate the role of ATO in protecting against atherosclerosis,
ApoE-/- mice were divided into two groups and fed a
high-fat diet for 3 months. One group was treated with ATO (2.5 mg
kg-1), and the other group was treated with vehicle
(ATO and control groups, respectively; Figure 1A). ATO significantly
reduced atherosclerosis development, as demonstrated by Oil Red O
staining of both the aortic sinus and en face preparations of the
entire aorta (Figure 1B, D, G, J). In addition, the lesion area and the
proportion of necrotic cores in plaques significantly reduced after ATO
treatment (Figure 1C, E, F), but the necrotic core area decreased
slightly (Figure 1I). In addition, ATO increased the collagen content in
plaques (Figure 1H, K). We further determined the effects of ATO on
plaque composition. ATO reduced macrophage accumulation, as indicated by
CD68 immunostaining (Figure 1L, M).
To determine whether the dose we used in this study was safe, we
examined the histological features of various tissues and organs (Figure
S1A, B). We also examined the levels of aspartate aminotransferase
(AST), alanine aminotransferase (ALT), urea acid (UA), and creatine
Kinase (CK) in ApoE-/- mouse plasma, apoptosis in
peripheral lymphoid tissues, and the proportion of peripheral white
blood cells (Figure S1D-G, S2). The results showed that the appropriate
dose we used (2.5 mg kg-1) did not cause significant
serological changes, histopathological changes, or extensive white blood
cell apoptosis. Further, there were no significant changes in the body
weight of ApoE-/- mice before and after ATO treatment
(Figure S1C). These results indicate that the dose of ATO used in
vivo (2.5 mg kg-1) attenuated atherosclerotic plaque
progression but did not cause significant toxicity in
ApoE-/- mice. Furthermore, our previous study has
shown how the ATO dose affects the viability of macrophages
(Fang et al. , 2021). Based on these
results, we chose the dose of ATO as 2.5 mg kg-1in vivo and the doses of 2.5 and 5.0 μM in vitro in this
experiment.