2005 Volume 38 Issue 5 Pages 339-341
Polymorphonuclear leukocytes (PMNs) infiltrating the chorioamnion is one causal agent of preterm delivery. Although the basement membrane (BM) has been proven to be a barrier against PMN migration in various tissues, there is a lack of data focusing on the relationship between PMN morphology and chorion laeve BM. Using peroxidase enzyme-cytochemistry, we morphologically studied PMN infiltration into the chorioamnion, especially the chorion laeve BM. The accumulated PMNs lay side by side just beneath the BM, while the cytoplasmic processes of some PMNs penetrated the BM. Peroxidase deposits appeared not only in the leukocyte granule but also on the phagosomes, indicating that PMNs at the site were activated. These features resembled those of activated PMNs migrating through a filter according to the gradient of chemo-attractant. The chorion laeve BM thus may be a barrier to PMN migration through the chorioamnion. Activated PMNs and BM may be involved in the pathophysiology of preterm delivery.