[Bone histomorphometry of lactating and no lactating hyperthyroid rats]. / Histomorfometria óssea de ratas hipertireóideas lactantes e não-lactantes.

The objective of this study was to verify if hyperthyroidism potentiates the osteopenia lactational. 24 adult female rats were distributed in four groups: euthyroid no lactating (control), euthyroid lactating, hyperthyroid no lactating and hyperthyroid lactating. 20 days after gestation, all the animals were necropsied. The thoracic and lumbar vertebrae, the femur and tibia were decalcified and processed for histomorphometric analysis. The euthyroid lactating group presented intense osteopenia in the studied bones. In the hyperthyroid no lactating group, there was not any change in trabecular bone percentage in none of the analyzed bone. In the hyperthyroid lactating group, there was osteopenia in the tibia and femur, similar to the one in the euthyroid lactating group. But the trabecular bone percentage in all the vertebral bodies was significantly larger in comparison with the euthyroid lactating group. It was concluded that the hyperthyroidism does not potentiate the osteopenia lactational in female rats, but it minimizes the vertebral osteopenia once it stimulates the osteoblastic activity.

Histomorphometry and expression of CDC-47 and caspase-3 in mammary glands of pregnant female rats with artificial hyperthyroidism.

The purpose of this study was to evaluate the effect of hyperthyroidism on mammary gland development and expression of two protein markers, CDC-47 for proliferation and caspase-3 for apoptosis in pregnant female rats. Thirty-six adult female Wistar rats were used in two groups: hyperthyroid and control. Rats were mated 60 days after the onset of thyroxine administration. Six animals/group were sacrificed on gestation days 7, 14, and 19. Artificial hyperthyroidism was induced by daily administration of thyroxine in the drinking water until the end of gestation. At the end of each period, rats were sacrificed, and their inguinal mammary glands were collected and processed for morphometric analysis. The percentages of epithelium, stroma, adipose tissue, and lacteal secretion were determined. Immunohistochemical analysis was also carried out using anti-CDC-47 and anti-caspase-3 antibodies to study proliferation and apoptosis, respectively. On the 19th day of gestation, thyroxine treatment significantly increased the percentage of mammary epithelium. Hyperthyroidism, however, did not change CDC-47 expression. The hyperthyroid group presented early lactogenesis and significantly larger lacteal secretion on the 19th day of gestation. There was no significant difference in caspase-3 expression between groups in any period. We may conclude that hyperthyroidism accelerates mammary gland development and increases lacteal secretion during gestation without increasing the proliferation rate and the expression of caspase-3.

Histomorfometria óssea de ratas hipertireóideas lactantes e não-lactantes / Bone histomorphometry of lactating and no lactating hyperthyroid rats

O objetivo deste estudo foi verificar se o hipertireoidismo potencializa a osteopenia causada pela lactação. Foram utilizadas 24 ratas adultas distribuídas em quatro grupos: eutireóideo não lactante (controle), eutireóideo lactante, hipertireóideo não-lactante e hipertireóideo lactante. Todos os animais foram necropsiados, 20 dias após a gestação. As vértebras torácicas e lombares, o fêmur e a tíbia foram colhidos, descalcificados e submetidos à análise histomorfométrica. O grupo eutireóideo lactante apresentou osteopenia intensa em todos os sítios ósseos estudados. No grupo hipertireóideo não-lactante, não houve alteração da porcentagem de tecido ósseo trabecular nos sítios analisados. No grupo hipertireóideo lactante, havia osteopenia na tíbia e no fêmur, semelhante à do grupo eutireóideo lactante. Mas a porcentagem de tecido ósseo trabecular em todos os corpos vertebrais foi significativamente maior em comparação ao grupo eutireóideo lactante. Conclui-se que o hipertireoidismo não agrava a osteopenia lactacional em ratas, mas minimiza a osteopenia vertebral por estimular a atividade osteoblástica.

The objective of this study was to verify if hyperthyroidism potentiates the osteopenia lactational. 24 adult female rats were distributed in four groups: euthyroid no lactating (control), euthyroid lactating, hyperthyroid no lactating and hyperthyroid lactating. 20 days after gestation, all the animals were necropsied. The thoracic and lumbar vertebrae, the femur and tibia were decalcified and processed for histomorphometric analysis. The euthyroid lactating group presented intense osteopenia in the studied bones. In the hyperthyroid no lactating group, there was not any change in trabecular bone percentage in none of the analyzed bone. In the hyperthyroid lactating group, there was osteopenia in the tibia and femur, similar to the one in the euthyroid lactating group. But the trabecular bone percentage in all the vertebral bodies was significantly larger in comparison with the euthyroid lactating group. It was concluded that the hyperthyroidism does not potentiate the osteopenia lactational in female rats, but it minimizes the vertebral osteopenia once it stimulates the osteoblastic activity.

[Proliferation, apoptosis and mammary gland histomorphometry of thyroxine-treated rats on lactation and after weaning and development of offspring]. / Proliferação, apoptose e histomorfometria da glândula mamária de ratas tratadas com tiroxina na lactação e ao desmame e desenvolvimento dos filhotes.

The purpose of this study was to evaluate mammary gland histomorphometry and proliferation rate and apoptosis of thyroxine-treated rats by CDC-47 and caspase-3 immunoexpression. The development of thyroxine-treated rats offspring was also evaluated. Thirty-six female rats were used, distributed in two groups, treated and non-treated with thyroxine. After 60 days of treatment, with thyroxine, rats were mated. Six animals/group were sacrificed on the 2nd and 21st days of lactation and on the 5th day after weaning. A significant difference was observed between groups only on the 5th day after weaning. Thyroxine treatment increased apoptosis rate, which was characterized by a higher caspase-3 expression in mammary epithelial cells. Thyroxine-treated mothers presented changed behavior, but there was no significant difference regarding taking care of offspring, as for cleaning offspring and keeping them warm. Taking into account sex and size of offspring, those from control and thyroxine-treated mothers presented no significant difference of weight and weaning. In conclusion, administering low doses of thyroxine increases apoptosis rate, which is characterized by the increased caspase-3 immunoexpression in mammary epithelial cells 5 days after weaning. But does not affect proliferation rate and development of thyroxine-treated rats offspring.

Proliferação, apoptose e histomorfometria da glândula mamária de ratas tratadas com tiroxina na lactação e ao desmame e desenvolvimento dos filhotes / Proliferation, apoptosis and mammary gland histomorphometry of thyroxine-treated rats on lactation and after weaning and development of offspring

O objetivo deste estudo foi avaliar a histomorfometria e a taxa de proliferação e apoptose da glândula mamária de ratas tratadas com tiroxina pela imuno-expressão de CDC-47 e caspase-3, respectivamente. Também foi avaliado o desenvolvimento dos filhotes de ratas tratadas com tiroxina. Foram utilizadas 36 ratas distribuídas em dois grupos, tratado com tiroxina e controle. Após 60 dias de tratamento com tiroxina, as ratas foram acasaladas. Seis animais/grupo foram sacrificados no 2° e 21° dias de lactação e no 5° dia após o desmame. Houve diferença significativa entre grupos apenas no quinto dia após o desmame. O tratamento com tiroxina aumentou a taxa de apoptose caracterizada pela maior expressão de caspase-3 nas células do epitélio mamário. As mães tratadas com tiroxina apresentaram comportamento alterado, mas não houve diferença significativa no que se refere aos cuidados com o filhote quanto a higienização e aquecimento. Levando-se em consideração o sexo e o tamanho da ninhada, os filhotes das ratas tratadas com tiroxina e controle não apresentaram diferença significativa de peso ao desmame. Conclui-se que a administração de baixas doses de tiroxina aumenta a taxa de apoptose, caracterizada pelo aumento da expressão de caspase-3 no epitélio mamário cinco dias após o desmame, mas não altera a taxa de proliferação celular e o comportamento materno.

The purpose of this study was to evaluate mammary gland histomorphometry and proliferation rate and apoptosis of thyroxine-treated rats by CDC-47 and caspase-3 immunoexpression. The development of thyroxine-treated rats offspring was also evaluated. Thirty-six female rats were used, distributed in two groups, treated and non-treated with thyroxine. After 60 days of treatment, with thyroxine, rats were mated. Six animals/group were sacrificed on the 2nd and 21st days of lactation and on the 5th day after weaning. A significant difference was observed between groups only on the 5th day after weaning. Thyroxine treatment increased apoptosis rate, which was characterized by a higher caspase-3 expression in mammary epithelial cells. Thyroxine-treated mothers presented changed behavior, but there was no significant difference regarding taking care of offspring, as for cleaning offspring and keeping them warm. Taking into account sex and size of offspring, those from control and thyroxine-treated mothers presented no significant difference of weight and weaning. In conclusion, administering low doses of thyroxine increases apoptosis rate, which is characterized by the increased caspase-3 immunoexpression in mammary epithelial cells 5 days after weaning. But does not affect proliferation rate and development of thyroxine-treated rats offspring.