HISTOMETRICAL PARAMETERS OF STROMA OF CHORIAL VILLI OF THE PLACENTA IN PREMATURE LABOR

Abstract

The purpose of the research–to establish some histometric parameters of the chorionic villistroma of the placenta during premature birth in comparison with physiological pregnancy.Material and methods. The material (30 placentas in premature births and 30 placentas inphysiological pregnancies) was fixed for 22-24 hours in a neutral buffered 10 % formalinsolution. Next, the material was dehydrated in an ascending battery of alcohols andimbedded in paraffin at 580C. Serial histological sections 5 μm thick were made on a sledmicrotome. After de-embedding, serial histological sections were stained with hematoxylinand eosin, histochemical staining for total protein with bromophenol blue according toBogheg, histochemical staining for collagen and fibrin with chromotrope – water blueaccording to N. Z. Slinchenko. In addition to the descriptive method of histopathologicalexamination, computer morphometry was performed on previously obtained digital copiesof optical microscopic images of the tissue (Delta Optical Evolution 100 microscope{planachromatic lenses according to the required optical magnification} and OlympusSP550UZ digital camera). Digital copies of the image were analyzed using a freewarecopy of the ImageJ v1.52 computer program specialized for digital histometric studies. In particular, the optical density of staining for total protein in the connective tissuefibers, the optical density of staining for collagen in the connective tissue fibers, andthe specific volume of the connective tissue fibers in the extravascular interstitium invarious types of chorionic villi were determined on digital copies of optical images usingcomputer microdensitometry. The obtained digital data were processed statistically. Inparticular, with the help of a copy of the free (freeware) computer program for statisticalcalculations PAST v 4.14, a preliminary test for the normality of the distribution wasapplied according to the Wilkie- Hahn- Shapiro test. For all studied statistical samples,according to this criterion, the hypothesis about the normality of the distribution wasnot rejected (at p=0.05), therefore, parametric methods of statistical analysis were used:calculation of the arithmetic mean and its error, the odd two-sided Student’s test. Alongwith the Student’s test, the non-parametric Mann-Whitney test was also used.The results. Concerning stromal cells, no differences were found between physiologicalpregnancy and preterm birth. But some changes were found in the fibrous component ofthe stroma of chorionic villi. In order to determine the state of the fibrous component of thestroma of chorionic villi, evaluation of it was carried out according to three parameters.The optical density of the staining of the connective tissue fibers for total protein andcollagen did not change in premature birth, however, a decrease in the «Specific volumeof the connective tissue fibers in the extravascular interstitium» indicator could be seen.Conclusions. According to the obtained histometric data, a decrease in the specificvolume of the connective tissue fibers in the extravascular interstitium of intermediateimmature, intermediate mature, and terminal villi is noted in premature birth comparedto physiological pregnancy, while the properties of the fibers themselves do not changeaccording to the optical density assessment of total protein and collagen.