The layers of the human placenta at term and resident lipid droplets.

(A) TEM of human placenta at term. MAT, maternal blood space; MVM, microvillous membrane; SCT, syncytiotrophoblast; CTB, cytotrophoblast; END, endothelium; FET CAP, fetal capillary; RBC, red blood cell; BL, basal lamina. Scale Bar: 1μm. (B-E) Lipid droplets (LD, arrow heads) in the human placenta can be detected by multiple staining methodologies. (B) Oil-Red O (C) Nile Red (D-E) Structured illumination microscopy (SIM, a super-resolution technique). Only the syncytiotrophoblast is imaged in (E). (F) The LD volume distribution in freshly delivered placenta is not different (One-way ANOVA) between cytotrophoblast (CTB) and syncytiotrophoblast (SCT) layers, as measured by SIM. (Data are mean ± SEM, n = 7, unpaired t-test). Scale Bar (B-E): 5μm.