In vivo effects of TGFβ1 on the growth of gastric epithelium in suckling rats

Abstract As the content of Transforming Growth Factor-β (TGFβ) wanes in the milk of lactating rat, an increase in TGFβ is observed in the gastric epithelia concomitant with differentiation of the glands upon weaning. Whereas TGFβ has been shown to inhibit the proliferation of gastrointestinal cells in vitro , its functional significance and mechanisms of action have not been studied in vivo . Therefore, we administered TGFβ1 (1 ng/g body wt.) to 14-day-old rats in which the gastric epithelium was induced to proliferate by fasting, and determined the involvement of signaling through Smads and the impact on epithelial cell proliferation and apoptosis. After the gavage, we observed the progressive increase of active TGFβ1 while TβRII-receptor remained constant in the gastric mucosa. By immunohistochemistry, we showed Smad2/3 increase at 60 min ( p p p kip1 at 2 h ( p p p in vivo . Further, the studies suggest a potential role for both milk and tissue-expressed TGFβ1 in gastric growth during postnatal development.