Morphological study of splenic megakaryocytopoiesis in White New Zealand rabbits in the end of gestation and postnatal period - DOI: 10.4025/actascianimsci.v25i1.2126

Estudou-se a megacariocitopoiese esplênica em coelhos da raça Nova Zelândia Branco, na fase fetal e pós-natal. Coletou-se o baço no 28o dia fetal e no 4o, 8o, 12o, 28o, 56o e 84o dia pós-natal. As células megacariocíticas apresentaram, morfologicamente, citoplasma que se alternou de escasso à abundante, variando de levemente basófilo à acidófilo com núcleos grandes, avermelhados, irregulares e cromatina variável, alternando-se de frouxa a densa. O número de nucléolos visíveis variou na dependência do padrão cromatínico, e evidenciaram atividade e seqüência megacariocitopoiética por todo o período estudado, pela presença de células maduras no 28o dia de vida fetal e no 84o dia do período pós-natal. Individualizaram-se, seqüencialmente, por megacarioblasto, promegacariócito, megacariócito cariocinético, megacariócito e metamegacariócito. Concluiu-se que a megacariocitopoiese esplênica, em coelhos, produziu plaquetas pela presença do ambiente estimulador da hemocitopoiese ou, mais especificamente, do microambiente indutor da megacariocitopoiese e trombocitopoiese.Splenic megakaryocytopoiesis was studied in White New Zealand rabbits in the fetal and postnatal phase. The spleen was collected at the 28th fetal day and at 4th, 8th, 12th, 28th, 56th and 84th days after birth. Morphologically, the megakaryocytic cells presented cytoplasm scarce to abundant, lightly basophilc to acidophilic, with large nucleus, reddish and irregular and variable amounts of chromatin loose to dense; the visible number of nucleoli varied depending on the chromatin pattern. It was evidenced megakaryocytopoietic activity and sequence all over the period of the study, by the presence of mature cells, in the 28th day of fetal life and in the 84th day of postnatal, presupposing a subsequent platelets production. It was individualized, sequentially, by megakaryoblast, promegakaryocyte, caryokinetic megakaryocyte, megakaryocite and metamegakaryocyte. We conclude that splenic megakaryocytopoiesis in rabbits produced platelets by presence of stimulator environment of hemocytopoiesis, or more specifically, by inductor microenvironment of megakaryocytopoiesis and thrombocytopoiesis