A pyridoindole antioxidant SMe1EC2 regulates contractility, relaxation ability, cation channel activity, and protein-carbonyl modifications in the aorta of young and old rats with or without diabetes mellitus

WOS: 000444557200004PubMed ID: 30054861We studied the effects of treatment with SMe1EC, a hexahydropyridoindole antioxidant, on vascular reactivity, endothelial function, and oxidonitrosative stress level of thoracic aorta in young and old rats with or without diabetes mellitus. The rats were grouped as young control (YC 3 months old), old control (OC 15 months old), young diabetic (YD), old diabetic (OD), young control treated (YCT), old control treated (OCT), young diabetic treated (YDT), and old diabetic treated (ODT). Diabetes was induced by streptozotocin injection and subsequently SMe1EC2 (10 mg/kg/day, p.o.) was administered to YCT, OCT, YDT, and ODT rats for 5 months. In young and old rats, diabetes resulted in hypertension, weight loss, hyperglycemia, and hypertriglyceridemia, which were partially prevented by SMe1EC2. SMe1EC2 also inhibited the diabetes-induced increase in aorta levels of AGEs (advanced glycosylation end-protein adducts), 4-HNE (4-hydroxy-nonenal-histidine), 3-NT (3-nitrotyrosine), and RAGEs (receptors for AGEs). The contractions of the aorta rings to phenylephrine (Phe) and KCL did not significantly change, but acetylcholine (ACh) and salbutamol relaxations were reduced in OC compared to YC rats. Diabetes induction increased Phe contractions in YC and OC rats, KCL contractions in YC rats, and did not cause further inhibition in already inhibited ACh and salbutamol relaxations in OC rats. We have achieved the lowest levels of ACh relaxation in YD rats compared to other groups. SMe1EC2 did not change the response of aorta to ACh, salbutamol and Phe in YC rats, and ameliorated ACh relaxations in OC and YD but not in OD rats. In YDT and ODT rats, increased Phe and KCL contractions, high blood pressure, and impaired salbutamol relaxations were amended by SMe1EC2. Phe contractions observed in YD and OD rats as well as KCl contractions observed in OC rats were the lowest levels when the rats were treated with SMe1EC2. When the bath solution was shifted to cyclopiazonic acid (CYP) or CYP plus Ca2+-free medium, the contraction induced by a single dose of Phe (3 x 10(-6) M) was more inhibited in YD and OD than in YC but not in OC rats. In SMe1EC2-treated rats, neither the presence of CFM nor CFM plus CYP exhibited a significant change in response of aorta to a single dose of Phe. These findings suggest that alpha 1-adrenergic receptor signaling is activated in both age groups of diabetic rats, diabetes activates K+-depolarization and calcium mobilization via Ca-V especially in the aorta of young rats, and sensitizes the aorta of old rats to the regulating effect of SMe1EC2. ACh relaxations were inhibited in YC rats, increased in OC rats and unchanged in YD and OD rats when aortic rings pretreated with TEA, an inhibitor of calcium-activated K+ channels (K-Ca), or 4-aminopyridine (4-AP), an inhibitor of voltage-sensitive K+ channels (K-V). ACh relaxations were inhibited in YCT, OCT, and YDT rats in the presence of 4-AP or TEA. In ODT rats, 4-AP did not change ACh relaxation but TEA inhibited. These findings suggest that the contribution of K-v and K-Ca to ACh relaxation is likely upregulated by SMe1EC2 when the relaxations were inhibited by aging or diabetes. We conclude that SMe1EC2 might be a promising agent for aging and diabetes related vascular disorders.Research Foundation of Gazi University [01/2010-126]; Research Foundation of Ankara University [10B336002]; COST Action [BM1203]; Slovak Academy of Sciences [APVV-51-017905]This article has been written by Prof. Karasu who is the leader of ADIC study group. We thank Ahmet Cumaolu and Elif Aydn for their technical help during measurement of some biomarkers. This work originally includes a part of the PhD thesis of Dr. Arzu Sakul and was partly supported by the Research Foundations of Gazi and Ankara Universities (GU-Project No. 01/2010-126, AU-Project No. 10B336002), COST Action BM1203 and the Slovak Academy of Sciences (VEGA grant APVV-51-017905)

The ultrastructural analysis of the effects of probucol on endocrin pancreas tissue ın experimentaly induced diabetes mellitus

Bu çalışmada Streptozotosin ile oluşturulan diyabet modellerinde önemli bir antioksidan olan probukolün B hücreleri üzerine koruyucu etkisinin elektron mikroskop düzeyinde incelenmesi amaçlanmıştır. Çalışmada 200 – 250 gr ağırlığında, 7 – 8 haftalık toplam 24 adet erkek sıçan kullanılmış ve 3 grup oluşturulmuştur. 1. grup kontrol (n=8) (sodyum sitrat, i.p., tek doz), 2. grup kronik (8 hafta) diyabet (n=8) (50mg/kg, i.p. tek doz STZ), 3. grup ise diyabet (8 hafta) + probucol tedavisi (300mg/kg/gün, 3 hafta) uygulanan grup (n=8) olarak ayrılmıştır. Süre bitiminde alınan pankreas dokuları LEO 906E Transmission Elektron Mikroskopta değerlendirilmiştir. Yapılan elektron mikroskobik incelemelerde diyabetik grup kontrol grubu ile karşılaştırıldığında, granül sayısının az olduğu, mitokondrion ve Golgi kompleksinde dejeneratif değişikliklerin varlığı gözlenmiştir. Diyabeti izleyen probukol tedavisi sonucunda ise granül sayısının normale yakın olduğu; ancak, organel dejenerasyonunun kısmen de olsa bulunduğu belirlenmiştir. Sonuç olarak, diyabetin B hücrelerinde oluşturduğu dejeneratif değişikliklerin probukol ile azaldığı; ancak, tamamen yok olmadığı belirlenmiştir.The aim of the present study is to investigate the protective effect of probucol, which is an antioxidant agent on beta cells in STZ induced diabetes mellitus model. In this study, 24, 7-8- week -old male rats, weighing 200-250 g were used, and the animals were divided into three groups. The control group received a single dose of sodium citrate (ip, n = 8), the 8 weeks chronic diabetes mellitus group received of a single dose 50 mg/kg STZ (ip, n = 8), the diabetes mellitus group received 300 mg/kg/day probucol for 3 weeks (n = 8). Electron microscopic examination revealed degenerative changes of mitochondria and Golgi complexes in diabetes mellitus group when compared with control group and beta cell granules were relatively decreased. When the samples from the diabetes mellitus group treated with probucol were evaluated, beta cell granule numbers were nearly normal, degeneration in organelle structure was reduced, but still present. As a conclusion probucol decreases the degenerative effects of diabetes mellitus on beta cells, but does not treat them all

Polyphenolic Extracts from Olea europea L. Protect Against Cytokine-Induced beta-Cell Damage Through Maintenance of Redox Homeostasis

Various pancreatic beta-cell stressors, including cytokines, are known to induce oxidative stress, resulting in apoptotic/necrotic cell death and inhibition of insulin secretion. Traditionally, olive leaves or fruits are used for treating diabetes, but the cellular mechanism(s) of their effects are not known. We examined the effects of Olea europea L. (olive) leaf and fruit extracts and their component oleuropein on cytokine-induced beta-cell toxicity. INS-1, an insulin-producing beta-cell line, was preincubated with or without increasing concentrations of olive leaf or fruit extract or oleuropein for 24 hr followed by exposure to a cytokine cocktail containing 0.15 ng/mL interleukin-1 beta (IL-1 beta), 1 ng/mL interferon-gamma (IFN-gamma), and 1 ng/mL tumor necrosis factor-alpha (TNF-alpha) for 6 hr. The cytotoxicity was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. Apoptosis was quantified by detecting acridine orange/ethidium bromide-stained condensed nuclei under a fluorescent microscope. The cells exposed to cytokines had a higher apoptotic rate, a decreased viability (MTT), and an increased caspase 3/7 activity. Both extracts and oleuropein partially increased the proportion of living cells and improved the viability of cells after cytokines. The protective effects of extracts on live cell viability were mediated through the suppression of caspase 3/7 activity. Oleuropein did not decrease the amount of both apoptotic and necrotic cells, whereas extracts significantly protected cells against cytokine-induced death. Cytokines led to an increase in reactive oxygen species (ROS) generation and inhibited glutathione level, superoxide dismutase activity, and insulin secretion in INS-1. Insulin secretion was almost completely protected by leaf extract, but was partially affected by fruit extract or oleuropein. Neither cytokines nor olive derivatives had a significant effect on cellular cytochrome c release and catalase activity. Moreover, the cells incubated with each extract or oleuropein showed a significant reduction in cytokine-induced ROS production and ameliorated abnormal antioxidant defense. The molecular mechanism by which olive polyphenols inhibit cytokine-mediated beta-cell toxicity appears to be involving the maintenance of redox homeostasis

Effects of antioxidant stobadine on protein carbonylation, advanced oxidation protein products and reductive capacity of liver in streptozotocin-diabetic rats: Role of oxidative/nitrosative stress

Background: Increased oxidative/nitrosative stress is important in the pathogenesis of diabetic complications, and the protective effects of antioxidants are a topic of intense research. The purpose of this study was to investigate whether a pyridoindole antioxidant stobadine (STB) have a protective effect on tissue oxidative protein damage represented by the parameters such as protein carbonylation (PC), protein thiol (P-SH), total thiol (T-SH) and non-protein thiol (Np-SH), nitrotyrosine (3-NT), and advanced oxidation protein products (AOPP) in streptozotocin-diabetic rats

Comparison of Melatonin Effect on Oxidant Status and Antioxidant Capacity in Liver and Heart of Young and Aged Rats

Background: Oxidative stress is involved in several pathologic conditions such as metabolic or cardiovascular disease, and in aging. Oxidative damage of biomolecules increases with age. Melatonin is the main neurohormone of the pineal gland and specific antioxidants may act against age-related oxidative damage. Objective: This study investigated the effects of administration of melatonin on aging-related parameters such as total oxidant status (TOS), hydrogen peroxide (H2O2) and lipid hydroperoxide (LOOH) levels and total antioxidant capacity (TAC) in the heart and liver in a rat model of aging. Methods: Young (3-month-old) and aged (24-month-old) male Wistar rats were divided into control and melatonin-treated groups. Melatonin was given for 21 days (10 mg/kg/day). At the end of the treatment period, TOS, TAC, H2O2, and LOOH levels were measured. Results: H2O2 in the liver, but not in the heart, was found to be increased in aged rats. Melatonin treatment diminished H2O2 in the heart of both group of rats compared with those of untreated control rats. Melatonin treatment also led to a decrease in H2O2 in the liver of aged rats. LOOH were found to be increased in both tissues of aged rats whereas melatonin treatment decreased LOOH levels in heart and liver tissues of aged rats. In the young rats melatonin also inhibited LOOH in liver. TAC in heart and liver was not found to be statistically different between young and aged rats. In young rats, melatonin treatment resulted in an increase in TAC that was associated with increased H2O2. In the liver and heart of the rats, TOS was increased with age and was ameliorated by melatonin treatment. Conclusion: Our results demonstrate that there is no dramatic overall decline in the antioxidant system with age. However, total oxidant status increased with age. Melatonin has a restorative effect on oxidative status