Structural changes in the rat placenta during the last third of gestation were for the first time assessed by stereology. Fischer female rats were euthanized on the day 16 or day 19 of gestation, and 35 placentas were collected. Three randomly selected placentas from each group were stereologically analyzed for the absolute volume. The proportion of the glycogenic cells and the trophoblast giant cells (TGC) in the basal part of the placenta was calculated using volume density. The absolute volume of the rat placenta on the day 16 of gestation was determined as 0.0638 cm3. The labyrinth comprised 0.0274 cm3, the basal plate 0.0271 cm3 and the decidua 0.0093 cm3. On the day 19 of gestation, the absolute volume of the placenta was 0.1627 cm3, the labyrinth occupied 0.0922 cm3, the basal plate 0.0596 cm3 and the decidua 0.0109 cm3. The volume density of trophoblast giant cells was 0.174 cm0 on the day 16 and 0.107 cm0 on the day 19 of gestation. The glycogenic cells comprised 0.379 percentage of the basal plate on the day 16 and 0.236 on the day 19 of gestation. We conclude that the absolute volume of the whole placenta and the labyrinth has increased from day 16 to the day 19 of gestation. In contrast, the volume density of glycogenic cells and trophoblast giant cells was higher on the day 16 than on the day 19 of gestation, probably due to the intensive trophoblast invasion during that time.

Advanced maternal age is known to be a risk factor for placental dysfunctions. The most common obstetric complications among older women would be considered as follows: gestational diabetes; pre-eclampsia; placenta praevia; preterm premature rupture of membranes and the risk of preterm delivery. The aims of research were to determine the impact of maternal age on the structure of terminal villi. The study was conducted on 60 human placentae of term pregnancy divided into two groups: the control group (30 placentae in pregnant women of age between 20 and 34) and the experimental group (30 placentae in pregnant women of 35 years of age and older). Stereological methods were applied to determine the volume density, surface density, total volume and total capillary surface area in terminal villi of placenta. The mean value of volume density of capillaries in terminal villi of placentae in older pregnant women is: Vvkks = (0,376 +/- 0,033) mm(0), and the mean value of total volume is: Vkks = (157,047 +/- 25,022) cm(3). The mean value of surface density is: Svkks = (64,783 +/- 2,543) mm(-1), and the mean value of total surface area is: Skks = (29,959 +/- 7,873) m(2). Volume density of capillaries in terminal villi of placentae is significantly lower in older pregnant women (p<0.001) in comparison to the younger pregnant women. The total volume, surface density and total capillary surface area in terminal villi of placentae are also significantly lower in older pregnant women (p<0.005) in comparison to the younger pregnant women. Statistically significant lower values of volume density, total volume, surface density and total capillary surface area indicate that there is a decreased metabolic transfer between mother and foetus.

With regard to intensive morphometric changes, morphometry as a method is mainly used for histogenetic studies of brain development in normal and experimental conditions. The aim of our study was to quantitatively analyse morphological parameters of the rat telencephalon during embryonic development. The investigation was carried out on semithin serial sections of rat brain from embryonic days 12 to 15. The volume densities (VV) of the lateral ventricles, the telencephalic neuroepithelium and the surrounding mesenchyme have been analysed stereologically and compared in examined embryonic stages. The neuroepithelial volume density was the smallest (28%) at E13 and the biggest (44%) at E15 (p<0.0005). The mesenchymal volume density was the smallest (32%) at E13 and the biggest (48%) at E14 (p<0.0005). The volume density of lateral ventricles was the biggest (40%) at E13 and the smallest (14%) at E15 (p<0.0005). Neurostereological methods have been making a very valuable contribution to neuroscience over recent years. We have used unbiased stereological counting methods to obtain objective quantitative parameters which show relations between some parts of rat embryonic telencephalon examined during its normal development.

Results of our study suggest that changes in glycoprotein content may contribute to restricted placenta growth and development. Higher expression of AXIN1 protein in IUGR placentae indicates a role of Wnt/β-catenin signaling pathway in pathology of placental development.

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