Crypt and villous epithelial cells in adult rat small intestine: numerical and volumetric variation along longitudinal and vertical axes.
Previous studies on the small intestines of certain adult rodents have suggested that the total number of crypt epithelial cells is equal to the number of villous epithelial cells. This possibility is examined on adult male Sprague-Dawley rats using design-based stereological methods. Small intestines were removed and divided into four segments of equal length. For each segment, numbers and mean volumes of epithelial cells in crypts and villi were estimated and then combined to give values for the entire intestine. Variations along the vertical (crypt-villus) axis and the intestinal long (pyloro-ileocaecal) axis were examined. Cell numbers in crypts and on villi varied from segment to segment. Villus:crypt cell ratios proximally were roughly double those found distally. The ratio for the entire intestine was, on average, 1.6 villous cells per crypt cell. These results demonstrate that numbers of crypt and villous cells need not be equivalent. Previous findings may reflect the fact that ratios fluctuate according to circumstances (e.g., with species, age, nutritional status, disease, etc) or may be due to technical differences in tissue sampling and morphometry. Cell volumes varied along the crypt-villus axis as well as between segments, confirming known gradients of maturation and activity. Finally, the size of the intestinal epithelial proliferon was calculated in terms of the average numbers of epithelial cells per villus and of crypt epithelial cells feeding on to it.
Zoubi
S A
SA
Department of Human Morphology, Queen's Medical Centre, University of Nottingham, UK.
Mayhew
T M
TM
Sparrow
R A
RA
D000818:Animals; D002452:Cell Count / Q000379:methods*; D002455:Cell Division / Q000502:physiology; D004847:Epithelial Cells; D004848:Epithelium / Q000648:ultrastructure; D007421:Intestine, Small / Q000166:cytology* / Q000648:ultrastructure; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley