摘要AIM: To study the morphology and ontogeny of dendritic cells of Peyer's patches in rats at different development periods.METHODS: The morphometric and flow cytometric analyses were performed to detect all the parameters of villous-crypts axis and the number of OX62+DC,OX62+CD4+SIRP+DC, and OX62+CD4-SIRP-DC in the small intestine in different groups of rats. The relationship between the parameters of villous-axis and the number of DC and DC subtype were analyzed.RESULTS: All morphometric parameters changed significantly with the development of pups in the different age groups ( F = 10.751, 12.374, 16.527,5.291, 3.486; P = 0.000, 0.000, 0.000, 0.001, 0.015).Villous height levels were unstable and increased from 115.24 μm to 140.43 μm as early as 3 wk postpartum.Villous area increased significantly between 5 and 7 wk postpartum, peeked up to 13 817.60 μm2 at 7 wk postpartum. Villous height and crypt depth ratios were relatively stable and increased significantly from 5.536, P = 0.0013). OX62+CD4+SIRP+DC subset levels detected in single-cell suspensions of rat total Peyer's patch dendritic cells (PP-DCs) increased significantly 2.07% 9-11 wk postpartum ( F = 7.216, P = 0.005).CONCLUSION: This study confirms the agerelated changes in villous-crypt axis differentiation in the small intestine. Simultaneously, there are also development and maturation in rat PP-DCs phenotypic expression. Furthermore, the morphological changes of intestinal mucosa and the development of immune cells (especially DC) peaked at 9-11 wk postpartum,indicating that the intestinal mucosae reached a relatively mature state at 11 wk postpartum.