Inhibition of rats extramedullary liver erytropoiesis by hyperbaric oxygen therapy

Costa-Val, Ricardo; Nunes, Tarcizo Afonso; Silva, Roberto Carlos de Oliveira e; Souza, Antônio Francisco de; Souza, Irene Edith de Puy e; Souza, Tatiana Karina De Puy e

doi:10.1590/s0102-86502007000200011

Cited by 3 publications

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References 16 publications

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“…After birth, bone marrow ( medulla ossea ) was proposed to be the proper niche where the formation of blood elements would continue for the lifetime as needed. Therefore, extramedullar hematopoiesis observed in liver 19, 20 , adipose tissue 21 , cerebellar hemagioblastoma 22 , meningioma 23 , or subdural hematoma 24 was perceived as unusual. However, in our study, it appeared essential for tumor growth and for regeneration of normal tissues.…”

Section: Introductionmentioning

confidence: 99%

I. Embryonal vasculature formation recapitulated in transgenic mammary tumor spheroids implanted pseudo-orthotopicly into mouse dorsal skin fold: the organoblasts concept

Witkiewicz

Schnitzer

2013

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Inadequate understanding of cancer biology is a problem. This work focused on cellular mechanisms of tumor vascularization. According to earlier studies, the tumor vasculature derives from host endothelial cells (angiogenesis) or their precursors of bone marrow origin circulating in the blood (neo-vasculogenesis) unlike in embryos. In this study, we observed the neo-vasculature form in multiple ways from local precursor cells. Recapitulation of primitive as well as advanced embryonal stages of vasculature formation followed co-implantation of avascular ( in vitro cultured) N202 breast tumor spheroids and homologous tissue grafts into mouse dorsal skin chambers. Ultrastructural and immunocytochemical analysis of tissue sections exposed the interactions between the tumor and the graft tissue stem cells. It revealed details of vasculature morphogenesis not seen before in either tumors or embryos. A gradual increase in complexity of the vascular morphogenesis at the tumor site reflected a range of steps in ontogenic evolution of the differentiating cells. Malignant- and surgical injury repair-related tissue growth prompted local cells to initiate extramedullar erythropoiesis and vascular patterning. The new findings included: interdependence between the extramedullar hematopoiesis and assembly of new vessels (both from the locally differentiating precursors); nucleo-cytoplasmic conversion (karyolysis) as the mechanism of erythroblast enucleation; the role of megakaryocytes and platelets in vascular pattern formation before emergence of endothelial cells; lineage relationships between hematopoietic and endothelial cells; the role of extracellular calmyrin in tissue morphogenesis; and calmyrite, a new ultrastructural entity associated with anaerobic energy metabolism. The central role of the extramedullar erythropoiesis in the formation of new vasculature (blood and vessels) emerged here as part of the tissue building process including the lymphatic system and nerves, and suggests a cellular mechanism for instigating variable properties of endothelial surfaces in different organs. Those findings are consistent with the organoblasts concept, previously discussed in a study on childhood tumors, and have implications for tissue definition.

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Section: Introductionmentioning

confidence: 99%

I. Embryonal vasculature formation recapitulated in transgenic mammary tumor spheroids implanted pseudo-orthotopicly into mouse dorsal skin fold: the organoblasts concept

Witkiewicz

Schnitzer

2013

F1000Res

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“…In the final phase of gestation, and up to the age of five years, erythrocytes are produced exclusively by the bone marrow 13 , although there are small areas of the liver that are capable of doing this 14 .…”

Section: Introductionmentioning

confidence: 99%

Hepatic damage in newborns from female rats exposed to the pesticide derivative ethylenethiourea

et al. 2012

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PURPOSE:To evaluate hepatic morphological-histological abnormalities in newborns from female rats exposed to ethylenethiourea. METHODS:A randomized study was conducted on fifty-five newborn Wistar rats were studied: 34 in the experimental group, whose mothers had been exposed to 1% ethylenethiourea; and 21 in the control group, whose mothers had received 0.9% physiological solution. The solution was administered via gavage on the 11 th day of gestation. Cesarean section was performed on the 20 th day of gestation. The newborns' livers were examined and any morphological-histological abnormalities were registered. The presence of megakaryocytes was quantified in 50 microscope fields, as the total number of these cells per mm 2 . RESULTS:The entire experimental group presented abnormalities of embryonic formation, with musculoskeletal anomalies, digestive system anomalies, hepatic congestion and friability, hydrops and delayed intrauterine growth. The histopathological analysis showed that morphological-histological hepatic destructuring had occurred in all entire experimental with removal of the hepatic trabeculae and severe hepatic megakaryocytosis. The mean megakaryocyte density ranged from 107.9 to 114.2 per mm 2 , and it was eight times greater than in the control group, thus characterizing a situation of extramedullary hematopoiesis. CONCLUSION:The fetal exposure to ethylenethiourea caused hepatic damage characterized by severe extramedullary hematopoiesis.Key words: Pesticides. Ethylenethiourea. Liver. Hematopoiesis, Extramedullary. Pregnancy, Animal. Animals, Newborn. Rats. RESUMO OBJETIVO:Avaliar alterações hepáticas morfohistológicas em recém-nascidos de ratas prenhes expostas à etilenotioureia. MÉTODOS:Realizado ensaio randomizado em animais de experimentação, onde foram estudados 55 recém-nascidos de ratas Wistar, 34 do Grupo Experimento, expostas a etilenotioureia 1% e 21 do Grupo Controle, em que a rata prenhe recebeu solução fisiológica 0,9%, ambos por gavagem no 11º dia de gestação. Realizada no 20º dia de gestação cesariana, analisados os fígados dos recém-nascidos e registradas as alterações morfohistológicas. Realizou-se a quantificação dos megacariócitos em 50 campos microscópicos, avaliando a quantidade total destas células por mm². RESULTADOS:Todos os recém-nascidos do Grupo Experimento apresentaram alterações na formação embrionária, com anomalias musculoesqueléticas, anormalidades do sistema digestório, congestão e friabilidade hepática, hidropisia e crescimento intrauterino retardado. A análise histopatológica mostrou desestruturação hepática morfohistológica em todos os recém-nascidos expostos à etilenotioureia, com destrabeculação dos hepatócitos e intensa megacariocitose hepática, apresentando média da densidade deLemos PVRB et al. -Acta Cirúrgica Brasileira -Vol. 27 (12) 2012megacariócitos de 107,9 até 114,2 por mm 2 sendo cerca de oito vezes maior que no Grupo Controle, caracterizando hematopoese extramedular. CONCLUSÃO:A exposição fetal a etilenotioureia provocou danos hepát...

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Immunoexpression of proliferating cell nuclear antigen (PCNA) in spleen of splenectomized rats with preservation of inferior pole, submitted to hyperbaric oxygenation

et al. 2013

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PURPOSE:To analyze PCNA immunoexpression on the inferior pole of the spleen of splenectomized rats submitted to hyperbaric oxygenation (HBO). METHODS:Were analyzed fragments of the inferior pole of the spleen of 20 male Wistar rats submitted to splenectomy with preservation of the inferior pole. The rats were divided in two groups: group A (n=10) without HBO and group B (n=10) submitted to HBO at 2, 5 atmospheres per 120 minutes, twice a day for three days and once a day for seven days. The groups were then subdivided in four subgroups: A15 (n=5), with euthanasia on the 15 th day; A45 (n=5), with euthanasia on the 45 th day; B15 (n=5) with euthanasia on the 15 th day and B45 with euthanasia on the 45 th day. Respectively on these days, fragments of the inferior pole of the spleen of all animals were collected and analyzed with the immunohistochemistry technique in order to evaluate PCNA expression. RESULTS:There was an expressive increase in PCNA immunoreactivity in the group B. The 45 day postoperative period resulted in a higher level of positivity than the 15 day postoperative period (p<0.01). CONCLUSION:The quantitative analysis of proliferating cell nuclear antigen positive suggests that hyperbaric oxygenation increases cellular proliferation, contributing to splenic regeneration.

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Inhibition of rats extramedullary liver erytropoiesis by hyperbaric oxygen therapy

Cited by 3 publications

References 16 publications

I. Embryonal vasculature formation recapitulated in transgenic mammary tumor spheroids implanted pseudo-orthotopicly into mouse dorsal skin fold: the organoblasts concept

I. Embryonal vasculature formation recapitulated in transgenic mammary tumor spheroids implanted pseudo-orthotopicly into mouse dorsal skin fold: the organoblasts concept

Hepatic damage in newborns from female rats exposed to the pesticide derivative ethylenethiourea

Immunoexpression of proliferating cell nuclear antigen (PCNA) in spleen of splenectomized rats with preservation of inferior pole, submitted to hyperbaric oxygenation

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