Estudo das alterações oxidativas, da capacidade antioxidante total e do óxido nítrico, em ratos submetidos à isquemia e reperfusão de membros posteriores

Abstract

Estudo das alterações oxidativas, da capacidade antioxidante total e do óxido nítrico, em ratos submetidos à isquemia e reperfusão de membros posteriores 1 Oxidatives alterations, total antioxidant status and nitric oxide study in rats submitted to ischemia and reperfusion of hind limbs. RESUMO Objetivo:Verificar o efeito do tempo de isquemia sobre as alterações oxidativas, a capacidade antioxidante total e o óxido nítrico, no músculo, no rim e no plasma de ratos submetidos à isquemia e reperfusão de membros posteriores. Métodos: 40 ratos machos foram distribuídos aleatóriamente em quatro grupos experimentais com 10 animais cada. Laparotomia, isolamento da aorta abdominal infra e justa renal. Grupos 1 e 3 (simulados) passagem do fio monofilamentar de polipropileno 7-0 ao redor da aorta sem liga-la e espera de 1 hora para o grupo 1 e de 6 horas para o grupo 3. Retirada do fio, espera de 15 minutos, eutanásia e colheita do material. Grupos 2 e 4 (experimentos), ligadura da aorta abdominal com o mesmo fio e isquemia de 1 hora no grupo 2 e de 6 horas no grupo 4. Retirada do fio e reperfusão por 15 minutos. Eutanásia e colheita de sangue por escoamento, músculo da pata posterior esquerda e rim esquerdo. Os parâmetros verificados foram: malondialdeído, capacidade antioxidante total e óxido nítrico. Resultados: Utilizou-se o teste "t"de Student e o teste de MANN-WHITNEY como testes não paramétricos e fixou-se em 0,05 ou 5% o nível de rejeição. Houve alterações estatísticamente significantes do malondialdeído no rim. A capacidade antioxidante total apresentou alterações significantes no rim, no músculo e no plasma enquanto que, o óxido nítrico, alterou apenas no plasma. Conclusão: A variação do tempo de isquemia provocou alterações significantes do malondialdeído, da capacidade antioxidante total e do óxido nítrico. Descritores: Isquemia. Reperfusão. Radicais livres. Estresse Oxidativo. Ratos ABSTRACT Purpose: To verify the effect of the ischemia time on the oxidative alterations, total antioxidant status and the nitric oxide, in the muscle, kidney and plasma, in rats submitted to ischemia and reperfusion of hind limbs. Methods: Forty male rats were randomized in four groups with ten animals each. Laparotomy, abdominal aorta infra e juxta renal isolation. Groups 1 and 3 (sham), passage of the polipropilen 7.0 monofilamentary thread aorta around without bending it and waiting time of 1 hour to group 1 and 6 hours to group 3. Withdrawal of the thread, waiting time of 15 minutes, euthanasia and material collection. Groups 2 and 4 (experiments), ligation of abdominal aorta with the same thread and ischemia of 1 hour in the group 2 and 6 hours to the group 4. Withdrawal of the thread and reperfusion for 15 minutes. Euthanasia and blood collection by flowing; withdrawal of the left hind limb muscle and of the left kidney. The parameters evaluated were: malondialdehyde, total antioxidant status and the nitric oxide. Results: The "T"Student test and the MANN-WHITNEY test have been used as nonparametrics tests and the rejection...

Different Protocols of Postconditioning Does Not Attenuate Mesenteric Ischemia-Reperfusion Injury After Short-Term Reperfusion

“…This finding stands great importance, since during early reperfusion there is higher formation of oxygen radicals, but they are not capable to induce structural damage to the tissue 6 . On the other hand, it is possible that ischemia-reperfusion damage was mitigated by post-conditioning if cell biomarkers were analyzed, but there was not enough time of reperfusion to detect intestinal mucosa morphological damage on optical microscopy.…”

Evaluation of the effect of allopurinol as a protective factor in post ischemia and reperfusion inflammation in Wistar rats

“…Other methods described in the literature to evaluate the consequences of I/R include the tissue anatomopathologic study such as the intestine 14,16 and the skeletal muscle, the quantification of plasmatic endotoxin 15,16 , superoxide dismutase 15,16,23 (SOD, an enzyme which removes the superoxide radical by accelerating its conversion into hydrogen peroxide), xanthine oxidase 23 , diamine oxidase 15,16 ( DAO, an enzyme primarily synthesized by the gastrointestinal mucosa cells, which reflect this tissue maturity and integrity), myeloperoxidase 13,14,16 (MPO, an indicator of neutrophil activity), malondialdehyde 7,16,23 (MDA, an indicator of lipid peroxidation), total antioxidant capacity 7 , and nitric acid 7 (NO, a vasodilator which indicates endothelial response).…”

“…Nowadays, it is known that the I/R generates free radicals which act on the lipids, carbohydrates, proteins and nucleic acids, a phenomenon called "oxydative stress", and lead to changes in the cell function and structure, which might result in death 7 .…”

Oxidative stress in dogs

“…In that study, the serum MDA concentration was determined by the TBARS method; that is, by the determination in the serum of substances reactive to barbituric acid, where the MDA is the main component. Several studies have also indicated the relationship between oxidative stress and the development of mammary tumors in dogs, mainly by correlating serum and tissue MDA values using the TBARS technique, as well as the levels of antioxidants such as vitamin E and vitamin C (SZCZUBIAL et al, 2004;FRANCISCO NETO et al, 2005;KUMARAGURUPARAN et al, 2005;ASKAR et al, 2009;GALVÃO, 2009). Askar et al (2009) demonstrated increased concentrations of MDA and nitric oxide (NO) and decreased serum concentrations of vitamin C (considered to be the first line of antioxidant defense) in 10 dogs with malignant breast neoplasms.…”

“…In that study, the authors confirmed the beneficial effectiveness of taurine and l-carnitine, both antioxidant agents already in use for the treatment of canine cardiopathies, and also of isoflavone from soy and pomegranate extract. Since the presence of oxidative stress in canine cardiopathies has already been established (FREEMAN et al, 2005), it is useful to determine the efficacy of natural substances having antioxidant capacity like the ones studied above, so that they can be included and prescribed as part of the treatment of canine heart diseases. In veterinary medicine, oxidative stress has also been linked with kidney disease (GALVÃO, 2009).…”