beta-carotene and Ischemia

In summary, much evidence supports the formation of toxic oxygen metabolites in ischemic reperfused tissue. Tissues are equipped with both an intracellular and extracellular antioxidant defense system. The defense system can also be divided into enzymatic and nonenzymatic defenses. Important components of a nonenzymatic antioxidant include alpha-tocopherol, ascorbic acid, and beta-carotene as well as other compounds that can react with radicals to form less reactive products such as sulfur-containing amino acids. Extracellular fluid comprises a second line of defense against oxidant injury. These extracellular antioxidants include ceruloplasmin, albumin, transferrin, haptoglobin, and uric acid. The oxidant injury can potentially occur during ischemia and reperfusion due to (1) an excess production of oxygen free radicals, (2) a decrease in antioxidant defenses, or (3) both. Because antioxidants function by removing the toxic oxygen metabolites, they are generally highly effective in reducing ischemia-reperfusion injury.

Topics: Animals; Antioxidants; Ascorbic Acid; beta Carotene; Carotenoids; Free Radicals; Humans; Ischemia; Oxidants; Reperfusion Injury; Vitamin E

Beta-carotene (BC) is a well-known antioxidant. However, increasing evidence shows that under severe oxidative conditions, BC can become pro-oxidant, an effect that may be enhanced in the presence of iron (II). In our earlier studies, we observed that despite increasing heme oxygenase-1 (HO-1) levels in the heart, the protective effects of BC have been lost when it was used at a high concentration. Since iron releases from heme as a consequence of HO-1 activity, we hypothesized that the application of an iron-chelator (IC) would reverse the lost cardiac protection associated with an elevated HO-1 level. Thus, in the present study, we investigated the effects of desferrioxiamine (DFO) in isolated, ischemic/reperfused rat hearts after long-term treatment with vehicle or high-dose (HD) BC. Vehicle or 150 mg/bw kg daily doses of BC were administered to the rats for 4 weeks, and then their hearts were removed and subjected to 30 min of global ischemia (ISA) followed by 120 min of reperfusion (REP). During the experiments, cardiac function was registered, and at the end of the REP period, infarct size (IS) and HO-1 expression were measured. The results show that DFO treatment alone during REP significantly ameliorated postischemic cardiac function and decreased IS, although HO-1 expression was not increased significantly. In hearts isolated from BC-treated rats, no cardioprotective effects, despite an elevated HO-1 level, were observed, while DFO administration after ISA resulted in a mild improvement in heart function and IS. Our results suggest that iron could have a role whether BC exerts antioxidant or pro-oxidant effects in ISA/REP-injured hearts.

Topics: Animals; Antioxidants; beta Carotene; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Iron; Ischemia; Myocardial Reperfusion Injury; Myocardium; Rats; Reactive Oxygen Species

Beta-carotene is a well-known antioxidant and precursor of Vitamin A that has a preventative role in the oxidative damage process. Our aim was to investigate the possible preventive effects of beta-carotene on oxidative damage via experimental ischemia and ischemia-reperfusion models in rat ovaries.. A traumatic vascular clamps were used for 3h to induce ischemia (Group 2, 3, 4, 5, 6, 7). The clamps were then removed to allow reperfusion for 3h (Group 3, 6, 7). Sham-operated rats (Group 1) underwent laparotomy without the induction of ischemia/reperfusion injury. Real-Time-PCR was performed to determine IL-1-beta, IL-6 and iNOS expression levels. Histopathological (H&E) and immunohistochemical staining (NF-kβ p65) processes were then performed. Finally, SOD, GSH, and MDA levels were determined.. Intense hemorrhagic areas were observed in both the ischemia and ischemia/reperfusion groups, whereas minimal hemorrhage was observed in the treatment groups. The ischemia and ischemia/reperfusion groups exhibited extreme immunoreactivity, detected by NF-kβ p65 staining; this reactivity decreased after the application of beta-carotene. The expression of IL-1-beta, IL-6, and iNOS in the injury groups increased significantly, whereas a dose-dependent improvement was observed in the treatment groups. Finally, MDA levels increased significantly and SOD and GSH levels decreased drastically in the injury groups. However, these values obtained from I/R groups were normalized after beta-carotene treatment.. In this study, we demonstrated via molecular and biochemical parameters the protective effect of beta-carotene, which is a potent antioxidant, on the experimental ischemia-reperfusion model.

Topics: Animals; Antioxidants; beta Carotene; Drug Evaluation, Preclinical; Female; Glutathione; Interleukin-1beta; Interleukin-6; Ischemia; Malondialdehyde; NF-kappa B; Nitric Oxide Synthase Type II; Ovary; Rats, Wistar; Reperfusion Injury; Superoxide Dismutase