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MORPHOMETRIC INDEXES OF PLACENTA OF PREGNANT FEMALE RATS FOUND IN CASE OF EXPERIMENTAL GESTOSIS

Автор Доклада: 
Toryanik E. L.
Награда: 
MORPHOMETRIC INDEXES OF PLACENTA OF PREGNANT FEMALE RATS FOUND IN CASE OF EXPERIMENTAL GESTOSIS

УДК 615.322:615.322:583.6321

MORPHOMETRIC INDEXES OF PLACENTA OF PREGNANT FEMALE RATS FOUND IN CASE OF EXPERIMENTAL GESTOSIS

Toryanik Erika, PhD (Med.), associate professor
National Pharmaceutical University

This article surveys the results of the morphological of uterine-placental complex formation. The obtained results demonstrate that NNLA injection to female rats caused considerable morphostructural changes in the uterus with prevailing hemodynamics disorder of the organ. Microcircular changes can be considered as the manifestations of vascular decompensation (paresis, blood stagnation), accompanied by disorders in the rheological properties of blood, endothelial dysfunction, abnormal vascular permeability. The other disorders of the endometrium and miometrium both in non-placental sites were of secondary importance. NNLA injection to pregnant females resulted in the placenta destructure accompanied by abrupt disruption in maternal and fetal circulation. The main pathology was excessive proliferation of connective tissue in fetal vessel gaps. It was first proven that enalaprili applied in treatment and as preventive measure can normalize gestation process in experimental gestosis: the state of uterine-placental tissue allows to “save” pregnancy of the most females and considerably reduce the postimplantational embyo death.
Key words: morphostructural changes in the uterus, uterine, placenta, fetus, intact test, disorders, fetal vessels, pregnancy, mucous, muscle fiber, tissue.

These days, perinatal medicine has been considerably enriched in numerous data diclosing the relationships between mother, placenta and fetus, both during normal pregnacy and in case of abnormal pregnancy.

It became possible thanks to the P.K. Anokhin's theory of systems genesis widely applied by morphologists, phisiologists and obstetricians that developed the concept of 'a functional system — mother-placenta-fetus'. The knowledge of fetus system genesis is required to conceive the etiology and pathogenesis of fetal deterioration.

It is morphologically certified that endocrine glands pathology in mothers lead to the changes of fetus endocrine glands.

Besides, due to the progress of perinatology - the study of the care of the developing fetus and the new-born baby both in normal pregnancy and in cases of pathology, - nowadays, a fetus is considered a competent person with certain rights and to whom special methods of diagnosis, treatment and precautions may be applied.

With the interests of the researchers focused on the regularities of fetal development, essential details of morphofunctional development of nervous, endocrine and immune systems have been revealed thus providing gomeostas of the developing organism.

Much attention is centered on the study of the influence of various harmful factors on the growing fetus both from the environmental side and mother's organism. Such pregnancy complication as arterial hypertension is a major problem of the present obstetrics. Its frequency varies within 2.5 and 16%.

According to the WHO (World Health Organization) data, the arterial hypertension is one of the main reasons of the perinatal diseases and mortality. From accessible resources no data revealing the patologic influence of mother's arterial hypertension on the deterioration of the reproductive health of the nation and with high indexes of reproductive losses are known.

However, the speed of the population decline in Ukraine is the highest in Europe and makes up 0.9-1.1% per year. The natural increase of the population is also the lowest and accounts for 1.2 per one woman, while for the simple reproduction it should be at least 2.2. [2, 3]

We couldn't find any experimental studies of the morphological indexes of the placenta ofpregnant female rats in cases of gestosis in the accessible resources, and it urged us to work on this matter.

Materials and methods. The experiments were conducetd on non-line pregnant female ratsweighing 180,00 — 200,00 g. Three groups of animals were arranged, wherein group 1 — intact test; group 2 — pregnant female rats which were provoked with gestosis by hypodermic injection — synthesis inhibitor NG — nitro - L - arginine (NNLA) ('Sigma' series 1096975) in a dose 50 mg/kg from 13th till 19thpregnancy day; group 3 - pregnant female rats with gestosis. It was discovered earlier that NNLA injections in period cause symptoms of preeclampsia — hypertension, proteinuria and poor growth of a baby. [8, 9, 7]

Taking into account the above, this type of gestosis has been chosen for our experiment.

Female rats with established estrous cycle in estrus phase were placed next to males (in relation 3:1). The date of the fixed pregnancy was defined after studying the uterine smears. The first day of pregnancy was considered the presence of spermatosoid in the smears of female rats. [1]

The uterus morphostructure and placenta of pregnant female rats were investigated on the 20thday of gestosis period. The experimental materials were fixed in 10% formalin solution, dehydrated in spirit with increasing concentration, and embedded in celoidin-paraffin. Micro-tears 3-4 mrm in thickness were stained in haematoxylin-eosin. [5] All the results obtained were statistically processed by Student's coefficient, the nonparametric Wilcoxon-Mann-Whitney test. [4]

The differences between separate samples were estimated by 95% level of significance.

All the investigations with animals were carried out in strict conformity with the conditions set out in the 'European Convention for the protection of vertebrate animals used for experimental and other scientific purposes1, Strasburg, 1986 with further ammendments made in 1998, and were approved at the First National Congress on Bioethics (Kiev, 2001).

Results and Discussions

The development of gestosis in group 2 of animals was accompanied by major clinical symptoms of pathology (with hypertension and proteinuria) and significant changes in uterus and placental complex that urged on the morphological study of uterus and placenta. [6]

NNLA injection to female rats produced morphostructural changes in the uterus with prevailing hemodynamics disorder of the organ.

The content of PAS-positive substances in the mucous membrane stroma has not been changed compared with the intact test. The collagen structure of the mucosa stroma has been changed slightly. Biometrics also revealed packed veins and hemorrhage (both among separate small bundles of muscle fibers and in enlarged connective tissue areas between different layers of biometry), disclosed vasodilatation and plasma soaking, connective tissue growth, and round cell infiltration. In some cases, muscular fiber thinning and vacuolation (signs of tissue hypoxia), weak saturated PAS-positive substances biometry were revealed. Typical disorders have been also found in the womb placental site in viable fetuses. In the upper layers of spongy tissue, there were visible detritus cells. In the deep layers, partial necrosis with fragmented cells, accumulation of cells similar to macrophages, damaged blood vessels with a coarse-collagen-fibre mesh in gaps were discovered. The long resistant erythrocyte stasis led to the disruption in blood circulation in the mentioned placental sites that caused necrosis and tissue jysis. Muscle fibres in the affected zone were vacuolated that manifested themselves as the hypoxia state of biometrics. The tissue saturation with PAS-positive material was reduced.

The enapril injection with NNLA has considerably enhanced offspring viability. In 50% females, there was 100% survival of fetuses, while in the rest - the average fetal death in offsprings did not exceed 18%. In all female rats, geodynamic disorders in the mucous wall womb horn was substatially reduced. Even in cases of some fetal resorption, no blood clots were found on the mucosa surface and in gaps of the most of uterine glands.

Proliferative processes in the surface epithelium have not been registered at all or were slightly visible. Among the morphostructure changes in the areas of fetal death: epithelial tissues were depleted in glycogen, endometrial stromal cells were increased, collagen component of uterus mucous membrane became coarse. With viable fetuses, the mucosa state in general was up to the standards.

Epithelial tissues are rich in glycogen, Mucosal stroma was rather swollen, however, it hadhistochemical characteristics, and properties of intact test group. In the restricted uterus areas of some females, there were some local, relatively small in size hemorrhages in the mucosa. Blood filling of mucosa in most pregnant rats was very close to the intact test. Biometry remained practically unchanged, only in some areas there were small cell clusters. In the placental bed of usterine horn wall there were not any necrotic or proteolytic changes. Although blood vessels were somewhat expanded, they kept the blood flow. Muscle fibers in the sponge area were slightly vacuolated. Biometry under the placental area was also partially vacuolated. The content of PAS-positive substances in the sponge tissue, placental bed and biometry matched the animal intact test.

In 90% cases, NNLA injection to pregnant females resulted in the placenta destructure, wherein in 83% cases - it caused significant damage. Architectonics was changed: decidual membranes were narrowed, while trophospongium was on the contrary much-enlarged. Decidual cell cytoplasm was partially vacuolated, and gaps in large maternal vessels were often enriched in leukocytic masses. Glycogenic spots in trophospongium were filled with eosinophilic homogeneous masses instead of typical cells. Periplacentitis was observed in 13% cases. The giant cells between decidual membranes and trophospongium were often vacuolated; the layer of these cells caccording to the norm - was enlarged.

Despite the fact that the labyrinth cavity as per the norm was slightly narrowed, it hadconsiderable pathological changes. Almost all studies showed that fetal-maternal circulations weredisrupted. Maternal vessels were usually widened and filled with aggregated erythrocytes. Sometimes gaps in maternal vessels contained closely spaced erythrocytes.

Fetal capillaries were not only devastated, in their gaps there was proliferation of fibroblast cell line, excessive connective tissue growth, causing abrupt decrease in metabolism. Perivascular connective tissues were also formed around the larger vessels. There were portions of placenta with stagnation of blood circulation. In these ischemic spaces there were only empty vessels. There was such an irreversible form of stromal-vascular dystrophy, as fibrinoid swelling and swelling of the epithelium and stroma. Fibrinoid masses were on the border between trophospongium and labyrinth and filled maternal vessels gaps. An exudative component occurred within the entire area. In 13% cases, these degenerative changes led to focal or widely spread necrosis with homogenized structure and loss of color differentiation. In some cases, it caused only fused cell masses. Glycogen in trophospongium and labyrinth was significantly reduced in comparison with the intact test.

Enalaprili injection considerably influenced the destructive processes and hemorheologicdisorders in the placenta, that were caused by the NNLA injection. The number of experiments with pathological disorders was decreased down to 26%. However, the complete absence of drastic changes in metabolism and body morphostructure should be mentioned. There were only some separate cases of hydropic degeneration of decidual cells, choral structure narrowing with slight connective tissue growth. Maternal blood flow was not disrupted, cases of periplacentitis were not detected. Histoarchitectonics was nearly close to normal. The content of glycogen in trophospongium and labyrinth reached the intact indexes and it manifested as the complete restoration of placental metabolism.

Morphometric indexes of placenta of pregnant female rats in case of experimental gestosis

 

Index

 

Intactcontrol

Pregnant

rats with gestose

Pregnant rats withgestose +
enalapril
5mh/kh

Cases of pathological changes detected,%

0

90

26,3

Width detsydualnoyi shell, mm

0,27

0,14*

0,16*

The width of the intermediate layer, mm

0,48

0,63

0,46*

Width labyrinth layer, mm

2,44

2,20

2,33

Glycogen content in the intermediate zone, ball

3,50

1,64

3,45*

Glycogen content in the maze, ball

3,75

1,86*

3,54*

Notes:

* p <0,05 - difference significant with reference to intact test

** p <0,05 difference significant with reference to the case of gestosis

Conclusions:

1. The results of morphological studies show that NNLA injection to female rats producedmorphostructural changes in the uterus with prevailing hemodynamics disorder of the organ. Microcircular changes can be considered as the manifestations of vascular decompensation (paresis, blood stagnation), accompanied by disorders in the rheological properties of blood, endothelial dysfunction, abnormal vascular permeability;

2. The other disorders of the endometrium and miometrium both in non-placental and placental sites were a secondary factor. NNLA injection to pregnant females resulted in the placenta destructure and inflammation (maternal and fetal zones), accompanied by abrupt disruption in maternal and fetal circulation. The main pathology was excessive proliferation of connective tissue in fetal vessel gaps;

3. It was first proven that enalaprili applied in treatment and prevention can normalize gestation process in experimental gestosis: the state of uterine-placental tissue allows to "save"pregnancy of the most females and considerably reduce the postimplantational embyo death.

References:

  1. Доклінічне вивчення лікарських засобівпризначених для лікування плацентарної дисфункції:методичні рекомендації / укладачіЛ.ВЯковлєваГ.ВЗайченкоА.ГЦипкун – К., ДФЦ МОЗУкраїни, 2009. – 59 с.
  2. Загальний огляд медико-демографічної ситуації та аналіз тенденцій у сфері охорони здоровяза останні пять років (2002-2006 р.р.) / Д.ДАстрахановМ.ВБанчукІ.ІВолинкін // Україна,Здоровя нації. – 2007. - №3 – 4 – с.7– 15.
  3. Лібанова Е.М. Низька тривалість життя населення – основний прояв тотальної демографічної кризи в Україні / Е.М. Лібанова // Журнал АМН України. – 2007. – т.13, №3 – с.411– 447.
  4. Лапач С.Н. Статистические методы в медико-биологических исследованиях с использованиемExcel / Лапач С.Н., Чубенко А.В., Бабич П.Н. – К.: Морион, 2001 – 320 с.
  5. Меркулов Г.А. Курс патологогистологической техники / Меркулов Г.А. – М.: Медицина, Ленинградское отделение, 1969 – 424 с.
  6. Морфологическое исследование плаценты и печени беременных крыс и их плодов при экспериментальном эндотоксикозе и протекции цеолитами / Е.А. Попп, Г.В. Правоторов, В.Д. Новиков, Ю.И. Склянов // Морфология. – 2005. – т. 128, №4. - с. 47-50.
  7. Pathophysiology of hypertension in response to placental ischemia during pregnancy: а central role for endothelin? / B.D. La Marca, B.T. Alexander, J.S. Gilbert / et al. / //Gender. Medicine. – 2008. – Vol.5, Suppl.1. – р.133 – 138.
  8. Placental insufficiency leads to developmental hypertension and mesenteric artery disfunction in two generations of Sprague – Dawley rat offspring / C.M. Anderson, F. Lopez, A. Zimmer / et al. / // Biol. Reproduction. – 2006. Vol. 74, 3 – р.538 – 544.
  9. Postovit L. M. Does nitric oxide play a role in the aetiology of preeclampsia / L.M. Postovit, M.A. Adams, C.H. Graham // Placenta. – 2001. – №22, Suppl A. – р. 51-55.
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MORPHOMETRIC INDEXES OF PLACENTA OF PREGNANT FEMALE RATS FOUND I

Статья интресна описанными морфологическими изменениями со стороны матки в условиях повышенной аретриальной гипертензиии у крыс. Четко обосновано примение антигипертезивных средств в данных условиях. Понравились проведенные исследования. Использование крыс с установленной гипертензией привело к получению достоверных результатов и убедительным данным касательно применения антигипертезивных лекарственных препаратов.

Very important article,

Very important article, especially for Ukraine, but I have some questions..... What classification of rat did you use?
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