Astaxanthin Reduces Oxidative Stress, but not Aortic Damage in Atherosclerotic Rabbits

Abstract

We evaluated whether carotenoid astaxanthin (ASX) could prevent oxidative and atherosclerotic damage in rabbits. Rabbits received regular chow (control) or an atherogenic diet (1% cholesterol) alone or supplemented with 50, 100, and 500 mg% ASX for 60 days (n = 5-9 per group). The atherogenic diet increased the serum cholesterol levels and the ratio of the intima/media area in the aortic arch. These changes were not prevented by ASX. Atherosclerotic rabbits showed increased aortic lipid peroxidation and nonprotein thiol group (NPSH) levels along with inhibition of glutathione peroxidase (GSH-Px). All ASX doses attenuated lipid peroxidation and the increase in NPSH but not the inhibition of GSH-Px. Aortic superoxide dismutase (SOD), catalase (CAT), and thioredoxin reductase (TrxR) activities were enhanced in atherosclerotic rabbits. Although all ASX doses prevented the increase in SOD activity, only 100 and 500 mg% ASX prevented the increase in CAT activity. Furthermore, these same doses partially prevented the increase in TrxR activity, while 50 mg% ASX completely prevented the effects of the atherogenic diet on this enzyme. However, ASX did not attenuate the hypercholesterolemia or the atherosclerotic lesions caused by the atherogenic diet at any of the doses evaluated. Our results indicate that although ASX did not prevent hypercholesterolemia or atherosclerotic lesions, it could play a beneficial role by preventing lipid peroxidation and changes in antioxidant enzyme activities.

Imbalance in superoxide dismutase/thioredoxin reductase activities in hypercholesterolemic subjects: relationship with low density lipoprotein oxidation

“…Elevated plasma cholesterol levels play a dominant role in cardiovascular diseases [1] as can be evidenced by the occurrence of atheroma in the aorta of hypercholesterolemic rabbits [14]. Accordingly, the AI, which reflects the relationship between the non-HDL cholesterol fraction and the HDL cholesterol fraction and is considered a possible indicator of a predisposition to heart disease [15], was directly correlated to the increase in LDL levels.…”

Astaxanthin prevents changes in the activities of thioredoxin reductase and paraoxonase in hypercholesterolemic rabbits

“…(16) Since ASX is carried in serum and hypercholesterolemia is an important event in atherosclerosis, the knowledge of ASX effects on the lipids and oxidative stress in the serum will complement previous data on the aortic tissue. Furthermore, the possible protective role of ASX on PON1 activity during experimental hypercholesterolemia has not been investigated.…”

“…ASX had no protective effect against LDL oxidation and atherosclerotic lesions in Watanabe heritable hyperlipidemic rabbits (15) or against aortic damage in atherosclerotic New Zealand rabbits. (16) However, ASX prevented the oxidation of human LDL in vitro (17) and stabilised atherosclerotic plaques in rabbits. (18) …”

Potential health‐promoting effects of astaxanthin: A high‐value carotenoid mostly from microalgae

“…Pashkow et al [69] suggested that there might be a potential therapeutic role for astaxanthin in the management of myocardial injury, oxidized low-density lipoprotein, and rethrombosis after thrombolysis, as well as other cardiac diseases such as atrial fibrillation. Augusti et al [77] indicated that although astaxanthin did not prevent hypercholesterolemia or atherosclerotic lesions caused by the atherogenic diet in rabbits, it could play a beneficial role by preventing lipid peroxidation and changes in antioxidant enzyme activities.…”