Opposite effects of fasting on TGF-beta3 and TbetaRI distribution in the gastric mucosa of suckling and early weanling rats.

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-beta3 (TGF-beta3) and TGF receptor-I (TbetaRI) 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-beta3 and TbetaRI 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-beta3 and TbetaRI distributions (P<0.05). We also observed that TGF-beta3 and TbetaRI 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-beta3 and TbetaRI 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-beta3 and TbetaRI indicate that they might be important for cell proliferation events in growth control.