High Resolution Optical Microscopy Technique Aplicated to Study of Placenta of Mummificated Foetuses in Swine.

In the sows, fetal mortality that occurs between Day 35 and term, causes on average the loss of more than one piglet per litter. During prenatal development, the ossification process begins very early in the fetal stage, where dead foetuses are not reabsorbed, but rather undergo a mummification process. The objective was to analyze and compare the porcine placental morphostructure of mummified foetuses and of normal placentation, through the application of high-resolution optical microscopy (HRLM). The placental tissues were collected immediately after delivery, was fixed in glutaraldehyde and processed by HRLM. Semi-thins sections were counterstained with toluidina's blue o with azur II and were observed in a light microscope. The analysis showed that the placentas of mummified foetuses have a different histoarchitecture than placentas from healthy foetuses. In the mesenchyme, the blood vessels showed different size, arrangement and morphological characteristics. Numerous capillaries arranged around areolas and venules were observed. Microthrombus formation was not observed. Cytoplasmic vacuolization, chromatolysis and cell detachment were observed in the trophoblastic epithelium. These all characteristics correspond to postmortem morphological changes. The HRLM allows the structural morphological evaluation and the digital morphometric analysis, with high definition and greater resolution. We consider that HRLM is a relevant tool that allows us to maximize the use of light field microscopy.