Navegando por Palavras-chave "reperfusion"
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- ItemSomente MetadadadosCaracterização morfofuncional da isquemia medular após pinçamento da aorta torácica descendente em ratos(Universidade Federal de São Paulo (UNIFESP), 2014-09-29) Prestes, Osias Martins [UNIFESP]; Miranda Junior, Fausto Miranda Junior [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Background: Paraplegia is a devastating complication of surgical repair of thoracoabdominal aortic aneurysms. Ischemic injury of spinal axons is an important determinant of neurological deficits. We assessed motor deficits and their correspondent density of motor neurons in an experimental model of spinal cord ischemia in rats. Objective: To evaluate whether motor deficits caused by transient cross-clamping of the descending thoracic aorta in rats are related to the density of motor neurons in the ventral horn of the thoraco-lumbar spinal cord. Methods: Twenty-five rats were randomized into 5 groups of 5 animals each. Four groups of animals had their descending aorta crossclamped for different periods of time (15, 20, 25 and 30 minutes), before reperfusion. Control group wasn?t submitted to ischemia. All animals were assessed for neurological deficit in their hind limbs by the Tarlov scale 60 minutes following reperfusion. The animals were then sacrificed and had their spinal cord removed. Density of motor neurons in the ventral horn of the thoraco-lumbar spinal cord was assessed by immunohystochemical quantitative analysis using the ImageJ image processing program. Other evaluated parameters included: neurological assessment, body temperature, heart rate and mean proximal arterial blood pressure, arterial blood gas, hemoglobin and hematocrit levels and serum concentration of sodium, potassium and lactate. Results: Post-operative serum lactate, bicarbonate and pH values were significantly different from pre-operative values in all groups of study. Animals submitted to 30 minutes of aortic cross-clamping had significantly lower levels of bicarbonate and pH than the control group. Tarlov scores in the 30-minute ischemia group were significantly lower than the other groups. In all animals, the density of motor neurons was directly related to the neurological score and inversely related to the duration of ischemia. Conclusion: Motor deficits caused by the occlusion of the descending thoracic aorta in rats are related to the density of motor neurons in the ventral horn of the thoraco-lumbar spinal cord.
- ItemAcesso aberto (Open Access)Isquemia e reperfusão de músculo sóleo de ratos sob ação da pentoxifilina(Sociedade Brasileira de Angiologia e de Cirurgia Vascular (SBACV), 2007-03-01) Brasileiro, José Lacerda; Fagundes, Djalma José [UNIFESP]; Miiji, Luciana Odashiro Nakao; Oshima, Celina Tizuko Fujiyama [UNIFESP]; Teruya, Roberto; Marks, Guido; Inouye, Celso Massaschi; Santos, Maldonat Azambuja; SBACV; Universidade Federal de Mato Grosso do Sul Hospital Universitário; Universidade Federal de São Paulo (UNIFESP); UFMS; UFMS Departamento de Clínica Cirúrgica; UFMS Hospital Universitário Comissão de Residência MédicaBACKGROUND: Reperfusion of the skeletal muscle worsens existing lesions during ischemia, since the production of reactive oxygen species, associated with intense participation of neutrophils, increases the inflammatory reaction that induces tissue changes. OBJECTIVE: To evaluate the morphological and immunohistochemical changes of the skeletal (soleus) muscle of rats submitted to ischemia and reperfusion with pentoxifylline. METHODS: Sixty rats were submitted to ischemia of the pelvic limb for 6 hours induced by clamping the left common iliac artery. After ischemia, group A animals (n = 30) were observed for 4 hours and group B animals (n = 30) for 24 hours. Six animals constituted the sham group. Pentoxifylline was applied only in the reperfusion period A2 (n = 10) and B2 (n = 10), and in ischemia and reperfusion periods in A3 (n = 10) and B3 (n = 10). The soleus muscle was evaluated by histological (fiber disruption, leukocyte infiltrate, necrosis) and immunohistochemical (apoptosis through caspase-3 expression) analysis. The non-parametric tests Kruskal-Wallis and Mann-Whitney (p < 0.05) were applied. RESULTS: The changes were more intense in group B1, with fiber disruption mean scores of 2.16±0.14; neutrophilic infiltrate of 2.05±0.10; and caspase-3 expression in the perivascular area of 4.30±0.79; and less intense in group A3, with means of 0.76±0.16; 0.92±0.10; 0.67±0,15, respectively (p < 0.05). Caspase-3 was more expressive in group B1 in the perivascular area, with mean of 4.30±0.79 when compared with group B1 in the perinuclear area, with mean of 0.91±0.32 (p < 0.05) CONCLUSIONS: The lesions were more intense when observation time was longer after reperfusion, and pentoxifylline attenuated these lesions, above all when used in the beginning of ischemia and reperfusion phases.
- ItemSomente MetadadadosProlonged cold ischemia accelerates cellular and humoral chronic rejection in a rat model of kidney allotransplantation(Wiley-Blackwell, 2012-03-01) Solini, Samantha; Aiello, Sistiana; Cassis, Paola; Scudeletti, Pierangela; Azzollini, Nadia; Mister, Marilena; Rocchetta, Federica; Abbate, Mauro; Pereira, Rafael Luiz [UNIFESP]; Noris, Marina; Mario Negri Inst Pharmacol Res; Ctr Anna Maria Astori; Universidade Federal de São Paulo (UNIFESP)One of the leading causes of long-term kidney graft loss is chronic allograft injury (CAI), a pathological process triggered by alloantigen-dependent and alloantigen-independent factors. Alloantigen-independent factors, such as cold ischemia (CI) may amplify the recipient immune response against the graft. We investigated the impact of prolonged cold ischemia and the subsequent delayed graft function on CAI in a fully MHC-mismatched rat model of kidney allotransplantation. Prolonged CI was associated with anticipation of proteinuria onset and graft function deterioration (ischemia: 90d; no ischemia: 150d), more severe tubular atrophy, interstitial fibrosis, and glomerulosclerosis, and increased mortality rate (180d survival, ischemia: 0%; no ischemia: 67%). in ischemic allografts, T and B cells were detected very early and were organized in inflammatory clusters. Higher expression of BAFF-R and TACI within the ischemic allografts indicates that B cells are mature and activated. As a consequence of B cell activity, anti-donor antibodies, glomerular C4d and IgG deposition, important features of chronic humoral rejection, appeared earlier in ischemic than in non-ischemic allograft recipients. Thus, prolonged CI time plays a main role in CAI development by triggering acceleration of cellular and humoral reactions of chronic rejection. Limiting CI time should be considered as a main target in kidney transplantation.