Opposite effects of fasting on TGF-β3 and TβRI distribution in the gastric mucosa of suckling and early weanling rats
Received 14 October 2008; accepted 27 March 2009. published online 15 June 2009.
Abstract
Objective
Our aim was to evaluate the effects of a dietary regimen (suckling or early weaning) and feeding status (fed or fasted) on the distribution of transforming growth factor-β3 (TGF-β3) and TGF receptor-I (TβRI) in the gastric epithelium of pups.
Methods
Wistar rats were used. At 15 d, half of the pups were separated from dams and fed with hydrated powered chow. On day 17, suckling and early weanling rats were subjected to fasting (17h). Four different conditions were established: suckling fed and fasted and early weanling fed and fasted. At 18 d stomachs were collected under anesthesia and were fixed in 4% formaldehyde for immunohistochemistry. The number of immunostained epithelial cells per microscopic field was determined for TGF-β3 and TβRI in longitudinal sections from the gastric mucosa.
Results
We found that during suckling, fasting reduced the number of immunolabeled cells per field of both molecules when compared with the fed group (P<0.05), whereas in early weaning, food restriction increased TGF-β3 and TβRI distributions (P<0.05). We also observed that TGF-β3 and TβRI were more concentrated in parietal cells in the upper gland in suckling pups, whereas after early weaning these were displaced to parietal and chief cells at the bottom of the gland.
Conclusion
Suckling and early weaning directly influence TGF-β3 and TβRI distributions in the gastric epithelium in response to fasting, such that early weaning anticipates the effects observed in adult rats. Furthermore, the differential concentrations of TGF-β3 and TβRI indicate that they might be important for cell proliferation events in growth control.
This study was supported by FAPESP (São Paulo, Brazil) (02/02936-9). D. Ogias was a recipient of a FAPESP fellowship (02/04745-6). E. R. de Andrade Sá was a recipient of a CAPES fellowship.
ABSTRACT