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Master's Dissertation
DOI
10.11606/D.42.2011.tde-22072011-160431
Document
Author
Full name
Priscila Moreira Figueiredo
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2011
Supervisor
Committee
Gama, Patricia (President)
Colquhoun, Alison
Suchecki, Deborah
Title in Portuguese
Papel da interação entre padrão alimentar, corticosterona e fatores de crescimento na regulação da proliferação celular no epitélio gástrico de ratos em desenvolvimento pós-natal.
Keywords in Portuguese
Células epiteliais
Estômago
Fatores de crescimento
Hábitos alimentares
Proliferação celular
Ratos
Abstract in Portuguese
O leite materno constitui uma rica fonte de nutrientes e peptídeos. O desmame precoce (DP) induz o aumento da proliferação e da diferenciação celular, e pode ser uma condição estressante capaz de elevar a corticosterona (CORT). Neste estudo, investigamos a interação entre padrão alimentar, CORT, TGFa e TGFb na regulação da proliferação celular na mucosa gástrica de ratos em desenvolvimento pós-natal. Utilizamos ratos Wistar em DP a partir do 15ºd, e observamos o aumento de CORT aos 16, 17 e 18d (p<0,05). No 17ºd, encontramos nível alto de TGFa e baixo de TGFb1 na mucosa gástrica (p<0,05). Para avaliarmos a ação da CORT, usamos o RU486, que ao reduzir a ação hormonal, estimulou a proliferação celular nos animais amamentados e DP (p<0,05), sem alterar os níveis de TGFa e TGFb. A sinalização para esses fatores foi estudada, e RU486 reduziu a ativação de ERK1/2 (p<0,05) no DP. Concluímos que a corticosterona circulante possui efeito antiproliferativo sobre a mucosa gástrica de ratos, e sua ação parece direta sem depender da regulação dos níveis de TGFa e TGFb.
Title in English
Role of the interaction among diet pattern, corticosterone, and growth factors on the regulation of cell proliferation in the gastric epithelium of developing rats.
Keywords in English
Cell proliferation
Dietary habits
Epithelial cells
Growth factors
Rats
Stomach
Abstract in English
Milk is a source of nutrients and active peptides. Early weaning (EW) leads to the increase of cell proliferation and differentiation, and can characterize a stressful condition to induce corticosterone (CORT). In the current study we investigated the interaction among dietary pattern, CORT, TGFa and TGFb on the regulation of cell proliferation in gastric mucosa of developing rats. We used Wistar rats submitted to EW on the 15thd, and we observed higher CORT levels throughout EW (p<0.05). At 17d, we also found higher TGFa and lower TGFb1 in the gastric mucosa (p<0.05). To evaluate CORT action, we used RU486 which antagonized the hormone and increased cell proliferation in both suckling and EW pups (p<0.05), without changing TGFa and TGFb1 levels. The signaling pathways triggered by these factors were studied and RU486 reduced ERK1/2 phosphorylation (p<0.05) in EW. We conclude that CORT is repressive for cell proliferation in the rat gastric mucosa, and its action seems to be direct, i.e. independent of TGFa and TGFb regulation.
 
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Publishing Date
2011-08-24
 
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