Morphometrical and cell kinetic studies of normal human colorectal mucosa. Comparison between the proximal and the distal large intestine.

Morphometric and cell kinetic studies were performed on normal mucosa in 30 specimens of surgically resected colorectum. The average crypt length was 372 +/- 57 microns in the proximal colon and 506 +/- 65 microns in the distal colon, and the average cell numbers per crypt column in these regions were 76.4 +/- 8.9 and 80.3 +/- 8.8, respectively. In the proximal and distal colon, goblet cells constituted 23.3 +/- 3.4% and 25.2 +/- 4.0%, respectively, of the total cells in each crypt, and in both regions entero-chromaffin cells constituted about 1%. The labeling indices of the proximal and distal colon were 9.4 +/- 3.9% and 8.2 +/- 2.2%, respectively. Combined microautoradiography and periodic acid-Schiff reaction on selected cases revealed that the labeling indices of columnar cells and goblet cells were 11.0 +/- 2.0% and 7.0 +/- 3.2%, respectively. It was suggested that the increased number of larger goblet cells in crypts of the sigmoid colon and rectum resulted in an increase of crypt length and a decrease in the labeling index. These results provide information on the morphological and cell kinetic characteristics of normal mucosa of the colon and rectum.