Effect of vitamin E supplementation on prostaglandin concentrations in aspirin-induced acute gastric injury in aged rats

Gastroprotective effect of small centaury (Centaurium erythraea L) on aspirin-induced gastric damage in rats

The aim of this study was to determine the antiulcer and antioxidant activities of Centaurium erythraea L (small centaury) in aspirin (ASA) induced acute gastric ulcer model. The gastroprotective effect of the 50% aqueous-ethanolic small centaury (SC) extract was investigated in rats at a dose of ASA 200 mg/kg body weight. Twenty-one Sprague-Dawley albino rats were divided into three groups of seven rats each as follows: (1) control group; (2) acute ASA-treated group and (3) ASA plus SC group. At the end of the 4-h drug administration, ulcer index, oxidant and antioxidant levels were measured and compared between the groups. The percentage of lesion area to total gastric surface area (ulcer index) was significantly reduced (77%) in ASA plus SC group as compared with acute ASA-treated group. The oral administration of ASA decreased catalase (CAT), reduced glutathione (GSH), and increased lipid peroxidation (LPO) levels. Although myeloperoxidase (MPO) activity was increased by ASA, it was found to be lower in the ASA plus SC group. GSH and Vitamin A levels were determined higher in the ASA plus SC group compared with ASA group. These results suggest that SC extract protects against ASA-induced damage due to its antioxidizing activity.

A combination of aspirin and gamma-tocopherol is superior to that of aspirin and alpha-tocopherol in anti-inflammatory action and attenuation of aspirin-induced adverse effects

Nonsteroidal anti-inflammatory drugs such as aspirin are used for pain relief and chemoprevention against cancer, but frequently cause gastric mucosal injury. We examined whether combinations of aspirin and alpha-tocopherol (alphaT) or aspirin and gamma-tocopherol (gammaT), with alphaT and gammaT being the two major forms of vitamin E, are better anti-inflammatory agents than aspirin alone, and whether these combinations alleviate aspirin-associated side effects. In the carrageenan-induced air-pouch inflammation model in the rat, aspirin (150 mg/kg) or a combination of aspirin and gammaT (33 mg/kg) inhibited proinflammatory prostaglandin E(2) (PGE(2)) by 70% (P<.02) at the inflammation site 6 h after inflammation was initiated. However, at 18 h, only the combination decreased exudate volume (15%; P<.05) and showed modest inhibition of PGE(2) (40%; P<.07) and lactate dehydrogenase activity (30%; P=.07) in the fluid collected at the inflammation site. gammaT, but not alphaT, spared aspirin-induced reduction in food intake, partially reversed aspirin-depressed gastric PGE(2) and attenuated stomach lesions. Surprisingly, the combination of aspirin and alphaT (33 mg/kg) did not show more benefits than aspirin alone, but worsened gastric injury and food intake reduction. Our study demonstrated that a combination of aspirin and gammaT, but not a combination of aspirin and alphaT, has some advantage over aspirin alone in terms of anti-inflammatory effects and attenuation of aspirin-induced adverse effects. This combination may be useful in complementing aspirin in the treatment of chronic inflammatory conditions and cancer.

Selenium and vitamin E increases polymorphonuclear cell phagocytosis and antioxidant levels during acute mastitis in riverine buffaloes

Antioxidant, antiinflammatory and phagocytic activities were studied in milk polymorphonuclear cells (PMNs) isolated from healthy buffaloes (group I) and during clinical mastitis with the treatment of Enrofloxacin alone (group II) and combined treatment with Enrofloxacin and Vitamin E plus selenium (group III). On days 0,3, 8 and 15 the milk Somatic cell count (SCC) were significantly higher in mastitic milk than in milk obtained from healthy buffaloes. In group II SCC decreased significantly on day 3 and day 8, however in group III reduction in SCC was observed on day 3, day 8 and day 15 (P < 0.05). The antiinflammatory activity was evaluated by determining nitrite plus nitrate (NOx) production in the milk PMNs before treatment and on day 8. NOx activity was significantly higher in mastitic milk than from healthy controls, both before and after treatment (P < 0.05). In group II and group III the activity decreased significantly on day 8 (P < 0.05). The Glutathione peroxidase (GSH-Px) activity was estimated in the milk polymorphonuclear cell (PMNs) supernatant. GSH-Px activity was significantly lower in mastitic buffaloes than in healthy controls, both before and after treatment (P < 0.05). In group II levels did not change in response to treatment, whereas in group III levels had increased significantly on day 8 (P < 0.05). The phagocytic activity (PA) (percentage of neutrophil that had phagocytosed 1-6 bacteria) and phagocytic index (PI) (average number of bacteria/ leukocytes counted in 100 cells) of the milk PMNs was significantly lower in mastitic buffaloes (P < 0.05). In group II the PA and PI did not change in response to treatment, whereas in group III both the parameters had increased significantly on day 8 (P < 0.05). The results of the present experiment indicated enhancement of antioxidative and cellular defense and reduction of somatic cell count in the mastitic animals treated with Enrofloxacin and Vitamin E plus Selenium as compared to the Enrofloxacin treatment alone. Hence Vitamin E plus selenium therapy may be added along with the antibiotics for effective amelioration of intramammary infection in buffaloes.

Reactive oxygen metabolites and anti-oxidative defenses in aspirin-induced gastric damage in rats: Gastroprotection by Vitamin E

OBJECTIVE

It has been proposed that neutrophil infiltration and oxygen radicals may be the important prime events that lead to mucosal injury induced by aspirin. Vitamin E acts as a potent antioxidant, and is capable of scavenging free radicals. The aim of this study was to evaluate the oxygen metabolites and anti-oxidative defenses in acute gastric damage induced by aspirin and to find the effects of Vitamin E.

METHODS

Ninety-six Wistar rats were divided into four groups of 24 rats each as follows: (1) the control group; (2) the ASA group that received 300mg/kg of ASA; (3) the Vitamin E plus ASA group and (4) the Vitamin E group that received Vitamin E (75 units) alone. At 3, 6, 9 and 24h after the drug administration, six rats were randomly selected from each group and gastric mucosal injury, prostaglandin E2, and the activities of myeloperoxidase, xanthine-oxidase, superoxide dismutase, glutathione peroxidase as well as glutathione level were measured and compared between the groups.

RESULTS

Oral administration of ASA caused acute gastric erosions and an increase in myeloperoxidase activity. It also decreased prostaglandin E2, superoxide dismutase activity, glutathione peroxidase activity and glutathione level. Concomitant administration of Vitamin E and ASA restored all the changes toward the control levels.

CONCLUSION

Free radicals and suppression of anti-oxidizing enzymes play important roles in gastric damage induced by aspirin. Increased myeloperoxidase activity suggests that activated neutrophils may be a major source of free radicals. Vitamin E protects against ASA-induced damage due to its anti-oxidizing activity.

Lifelong aspirin supplementation as a means to extending life span

Arising from an initiative by the National Institute of Aging (NIA) requesting novel proposals challenged with increasing lifespan and longevity, our laboratory has generated a hypothesis to test the efficacy of lifelong, low-dosage aspirin administration as a means to achieving this goal. The intervention testing program (currently underway) proposing aspirin as an anti-aging agent evolved from the multitude of properties encompassed in aspirin and the potential of these attributes to prevent the cellular and functional declines, particularly from inflammatory and oxidative sources, evidenced to contribute to aging. Aspirin is a widely administered, cheap, anti-inflammatory, and antioxidant compound that has a variety of positive effects on the immune system and cardiovascular health. Notably, aspirin may affect oxidant production, cytokine responses, and block glycooxidation reactions, thus posing it as a triple threat against the symptoms of aging. Whether aging is molded by interplay between oxidative stress and inflammatory mediators has received little attention; however, we and other laboratories have explored this notion and have observed an elevated inflammatory status with age. Stemming from these observations and in view of the limited success of antioxidant therapies in improving lifespan in long-lived species, in this article we propose a protocol to examine life-long use of a very low dose anti-inflammatory compound such as aspirin to engage the inflammatory and endogenous oxidative insults accompanying aging and, in so doing, attempt to increase maximum and mean life span.

Effect of Aframomum melegueta. Seed Extract on Castor Oil-Induced Diarrhea

The effect of the aqueous (aq) seed extract of Aframomum melegueta. K. Schum. (Zingiberaceae) on castor oil-induced diarrhea, intestinal fluid secretion, and gastrointestinal transit was investigated in the study. Castor oil (10 ml/kg, p.o.) induced copious diarrhea in all rats 3 h after treatment. Furthermore, it produced a significant increase in the volume of intestinal fluid secretion in rats and also enhanced intestinal transit in mice. The aq seed extract of A. melegueta. (100-500 mg/kg, p.o.) offered significant protection against diarrhea induced by the oil. At a dose range of 250-500 mg/kg, the extract reduced significantly the volume of fluid secretion in castor oil-treated rats. At these doses, it also demonstrated a significant antitransit activity in a dose-related manner. Acetylsalicylic acid (100 mg/kg, p.o.) delayed diarrhea and reduced the number of animals with diarrheal droppings to 20%. At the same dose level, acetylsalicylic acid reduced significantly the volume of intestinal fluid secretion but lacked antitransit property in castor oil-treated animals. N.-Nitro-L-arginine methyl ester (L-NAME) (2.5-10 mg/kg, i.p.) dose-dependently reduced the number of animals with diarrhea. At 50 mg/kg i.p., it offered 100% protection against diarrhea induced by the oil. Furthermore, L-NAME (10 mg/kg, i.p.) significantly inhibited both the intestinal fluid secretion and gastrointestinal transit induced by castor oil. However, L-NAME (10 mg/kg, i.p.) did not significantly modify the antidiarrheal effect of A. melegueta.. L-Arginine, a substrate of nitric oxide synthase or isosorbide dinitrate, a nitric oxide donor, did not alter the effect of A. melegueta. on diarrhea. Ascorbic acid (100 mg/kg, p.o.) and α.-tocopherol (20 mg/kg, p.o.) reduced the number of animals with diarrhea to 80% and 70%, respectively. However, they both lacked significant activities on intestinal fluid secretion and gastrointestinal transit induced by castor oil. The combination of ascorbic acid (100 mg/kg, p.o.) or α.-tocopherol (20 mg/kg, p.o.) with A. melegueta. (500 mg/kg) offered higher protection against diarrhea than the extract alone. Considering these results together, it may be inferred that Aframomum melegueta. seed extract may be a useful antidiarrheal agent.

Effects of esomeprazole magnesium on nonsteroidal anti-inflammatory drug gastropathy

It has been proposed that tissue damage induced by nonsteroidal anti-inflammatory drugs is related to increased tissue free radical production with antioxidant depletion. We have shown that esomeprazole increases gastric total antioxidant capacity in mice and, therefore, hypothesized that the protective effect of esomeprazole during treatment with a nonsteroidal anti-inflammatory drug is related to increased gastric antioxidant capacity and decreased tissue free radical production. A/J mice received one of four treatments by daily gavage: saline in vehicle (control), indomethacin, esomeprazole, or indomethacin and esomeprazole. After 10 days, all mice were sacrificed and validated assays were used to measure gastric total antioxidant capacity, lipid peroxide levels, and myeloperoxidase activity. Indomethacin-treated mice developed weight loss and melena. No mice receiving indomethacin and esomeprazole died, but the death rate while receiving indomethacin was 38% (chi2, P = 0.05). Gastric lipid peroxide levels increased in mice receiving indomethacin treatment compared to treatment with esomeprazole and indomethacin (P = 0.03). There was a strong trend (P = 0.08) toward increased gastric total antioxidant capacity in mice receiving esomeprazole and indomethacin compared to mice receiving indomethacin. Gastric myeloperoxidase activities were not different among the four groups. Esomeprazole significantly improved survival in mice that received indomethacin, reduced free radical production, as estimated by lipid peroxide levels, and appeared to increase gastric total antioxidant capacity. The mechanisms for the beneficial effects of esomeprazole in the treatment of gastropathy are more complex than previously thought.