Purpose: Foods are absorbed mainly in the small intestine. Water and electrolytes are absorbed in the large intestine.
Fasting is associated with structural and functional alterations in the gastrointestinal system. In the present study, we
aimed to investigate the histological and histochemical alterations in the mucosa of rat colon induced by short and
long term fasting.
Materials and Methods: In the present study, twenty-eight female Wistar rats were used. During starvation, animals
had free excess to water. Animals were fed for the last time and then at the end of the following 1st, 6th, 12th, and
36th hours and 2nd, 4th, 7th days, samples were obtained from colon.
Results: There was no histological change in colonic mucosa at the end of 1st. and 6th. hours. At the end of 12th.
hour, erosion of the surface epithelium was seen. At the end of 36th. hour, in addition to this finding, lymphocyte
infiltration in the lamina propria and dilatation of blood vessels were observed. At the end of 48th. hour, flattening
of the surface epithelium and that of Lieberkühn crypts, degeneration of the epithelium of the crypts and widening
of their lumen were observed. There were many apoptotic and mitotic cells in the crypt epithelium. At this stage,
dilatation of blood vessels was observed in the submucosa. At 4th day, these findings were more obvious.
Degeneration of the epithelium of Lieberkuhn crypts and oedema in the submucosa were seen. At 7th. day,
degeneration of the surface epithelium and that of Lieberkuhn crypts were prominent. Sometimes, it was difficult to
recognise the crypts because of their degeneration. The number of apoptotic and mitotic cells was increased.
Amount of the secretion on the surface and in the lumen of Lieberkuhn crypts and the number of goblet cells were
clearly decreased.
Conclusion: It is concluded that fasting causes important structural changes in the colonic mucosa and these
alterations become more obvious as the duration of the starvation prolongs.
Key Words: Fasting, Rat, Colon, Histology, Histochemistry
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