The worsening of ecological situation nowadays is one of the main factors in the abnormalities of reproductive function of woman and the factor of risk for the baby´s health . Among the most dangerous anthropogenic polluters of environment the leading position is hold by plumbum and its compounds [2, 3, 4]. At the same time a lot of questions are still not clear, including morphofunctional changes of placenta while the influence of plumbum, which lead to the abnormalities in the development of fetus and newborn [1, 5]. Thereby the examination of maternal-fetus relations in the conditions of lead intoxication needs the comprehensive and system approach.
Materials and methods
The experiment was carried out with the observance of principles of humanity that were stated at the directions of European community (86/609/ЕЕС) and the declaration of Helsinki and due to the demands of rules of carrying out the works using experimental animals.
In the experiment there participated 10 sexually matured pedigreeless white rats-females with the weight of 200,0-250,0 g. And their 10 young rats on the 30th day of postnatal period of development. The first group of animals (control) was compiled from: 5 female physiologically pregnant, 10 young rats at the 30th day of postnatal period of development. These group of animals was situated at the general routine of vivarium. The second group (experiment) was compiled from: 5 females, who from the moment of revealing of embryo of labyrinth (8th day of pregnancy) daily peroral got the acetate of plumbum in thedose of 45 mg/kg of body wheight, 10 young rats at the 30th day of postnatal period of development. All rats were decapitated under the ether narcosis.
For the electronically microscopic research the pieces of placenta were fixed in the 2,5% solution of glutaraldehyde to the 0,1М phosphate buffer (pH=7,2). Fixation was carried out in the 1% solution of osmic acid to the 0,2М phosphate buffer (pH=7,2). The embedding of material was carried out to the compound epon-araldite. The contrast of ultrathin section was carried out with the uranyl acetate and the citrate of plumbum. Received material was looked through the electronic microscope ЭМ-125.
For the microscopical research the material was fixed with the 10% solution of neutral formalin, and after the dehydration was embedded into the paraffin. Sections were prepaired with the thickness of 5 micrometers and were dyed with hematoxylin and eosin.
The definition of the substance of plumbum in the placenta, liver and kidneys was carried out with the method of atomic absorption spectrometry. The degree of development of posterity was valued by the changes of their mass.
Numerical results were worked up statically with the use of t-criterion of Student and pair correlated analysis.
Results and their discussion
Received with the help of atomic absorption spectrometry facts showed that in the controle the substance of plumbum in the placenta of pregnant rats formed 2,75±0,51 mg/kg of natural weight, and in conditions of lead intoxication - 7,97±0,78 mg/kg of natural weight Р≤0,002), that 2,9 times more in compare with the intact animals.
30-days young rats of control group had the substance of plumbum in the liver 0,95±0,069 mg/kg of natural weight. The young rats of analogous age who had received acetous plumbum at the period of intrauterine development had the concentration of plumbum in the liver 1,26±0,098 mg/kg of natural weight (Р≤0,05), that 1,3 times more in compare with the control.
The substance of plumbum in the liver of 30-days young rats, which were born from rats with the physiological pregnancy, had very high affirmative correlation with its substance in the placents. The coefficient of correlation was 0,731 (Р<0,05). Young rats, mothers of which had taken the acetate of plumbum, had these affirmative dependence become stronger, and the coefficient of correlation was 0,828 (Р<0,01) (fig. 1).
Figure 1. Correlation between the substance of plumbum in the placents of rats and in the liver of their posterity at the 30th day of postnatal development
- control (physiological pregnancy),
- experimental (lead intoxication of female)
In the controle in the kidneys of young rats the substance of plumbum was 0,80±0,087 mg/kg of natural weight, in the experiment - 2,56±0,410 mg/kg of natural weight (Р≤0,01), what 3,2 times more in compare with the young rats, who was born by intact females.
The substance of plumbum in the kidneys of posterity, born by the rats with the physiologically pregnancy, also had high affirmative correlation with its substance in the placenta. The coefficient of correlation was 0,754 (Р<0,01). Young rats, mothers of who had received the acetate of plumbum these dependence were more manifested and was 0,887 (Р<0,001) (fig. 2).
Figure 2. Correlation dependence between the substance of plumbum in the placenta of rats and in the kidneys of their posterity at the 30th day of postnatal development
- control (physiological pregnancy),
- experimental (lead intoxication of female)
The accumulation of plumbum in the organs of young rats of experiment group testify to its passing through the placenta from the mother´s blood to the fetus. As the researches showed in the conditions of lead intoxication of mother organism the greatest occurrence of plumbum posterity has in the kidneys, what is connected with their high sorption activity.
Electronically-microscopic researches showed that daily introduction to the pregnant females of white rats the acetous plumbum in the dose of 45 mg/kg leads to the derangement of compensatory mechanisms of placental barrier, which is expressed by the refinement of the cyto- and syncytiotrophoblast, vacuolization and clarification of cytoplasmic matrix, decomposition of mitochondrion, diminution of intercelluar contacts between the cyto- and syncytiotrophoblast elements. Against the background of edema and destruction of trophoblastic structures of labyrinth zone of placenta it was observed the presence of regions with the numerous osmiophil formations, apparently which were the deposits of plumbum.
Microscopical researches showed that 30-days young rats of experiment group had the plethoric tissues of liver, liver´s beams are saved, but along the periphery from the central veins their structure is "diffused". In the same zones were observed hepatocytes with the powdered, in the same places atomized fat dystrophy. The form of hepatocytes is varyable, sometimes were found hypertrophied cells. The nucleuses of cells of round shape, hyperchromic with the reticulate structure of chromatin. The cytoplasm is swelled, grainy nature, some places has single small transparent and semitransparent vacuoles. Intralobular sinusoid capillaries are insignificantly widen (edema), filled with serous licuid. The lumens of the majority of central and interlobular veins have the erythrocytes. It was observed the fibrosis of the central veins´ walls. In the portal tracts were found the areas of ill-defined lymphohistiocytic infiltration.
In the kidneys of 30-days young rats of experiment group was found the abnormality of nephritic haemodynamics, dystrophically-moronic changes of epithelium of canaliculuses. There was observed the widening and hyperemia of vessels of cortex of kidney , the substance in them partially laky erythrocytes. In the epithelium of nephritic canaliculuses was found necrobiosis and necrosis of separated groups of cells. The interfaces of other epitheliocytes are diffused. The nucleuses of these cells are of round shape, with the friable reticulate chromatin. In the some nucleuses are visible small hyperchromic grains - the mark of possible reksis of nucleuses. In the lumen of certain nephritic canaliculus are founded transparent masses, possiblyof hyaline. In the lumen of other canaliculus are found the accumulations of destroyed epithelial cells.
The observations of the development of the posterity of white rats showed, that the mass of young rats at the 30th day after birth while the physiological pregnancy was 41,54±1,16 g, and in conditions of lead intoxication - 37,46±1,77 г (Р≤0,05), that is 9,82 % less than control indicators.
The results of research showed that the introduction to the pregnant rats the acetous plumbum at the dose of 45 mg/kg leads to the derangement of compensatory mechanisms of placental barrier, cause in the liver and kidneys of posterity the hemomicrocirculational abnormalities and distrophyc changes.
The decrease of the body weight of posterity of white rats apparently connected with that plumbum when it accumulates in the organisms of animals, demand the considerable expenditure of energy on its elimination, and also can be the result of abnormalities of metabolic, transport and other functions of learnt organs, which are extremely important for the guaranteeing of normal development of organism.
This work was carried out in the network of realization of Federal Target Program "Scientific and scientifically-pedagogical personnel of innovative Russia" at 2009 - 2013 years on topic " The influence of factors of environment to the morphofunctional condition of organism", state contract №П2030
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