Differential cell kinetics in the ileum and colon of germfree rats

Our aim was to study the cell kinetics and epithelial structure in the ileum and colon of conventional and germfree AGUS rats by means of a classic stathmokinetic technique. A slight hyperplasia was observed in the villi of germfree animals (p < 0.05), associated with a comparatively short cell cycle time. The crypt cell production rate was reduced in the colon of germfree rats (p < 0.05), and their crypts contained fewer cells than those of conventional animals (p < 0.05). It is concluded that intraluminal bacteria influence cell proliferation in the colon. The absence of microflora prolongs the cell cycle time and reduces the proliferative activity in the colonic crypts, which contributes to a steady state that is different from that of conventional animals.