[Effect of experimental acute postnatal and mixed hypoxia on the morphological state of the rats liver stromal...

Introduction: In children population of Ukraine the diseases of the gastrointestinal tract are quite common, among which a significant number of cases occur in liver diseases. The complexity of the liver functions formation in antenatal and intranatal periods, its morphofunctional immaturity lead to the high sensitivity of this organ to the influence of various factors from the mother organism. Actual issues are the detection of the mother's pathology influence on the formation of diseases «cargo» in children remote stages of ontogenesis. In literature there are no data about the influence of hypoxia as the most common damaging factor in antenatal, intranatal and postnatal periods on the liver morphofunctional state of children of different ages, including its stromal component. The aim of the study was the detection of morphological features of the stromal component of the rats liver, which were in different terms of postnatal ontogenesis, exposed to acute postnatal and mixed hypoxia.

Materials and methods: The study material was the rats liver tissue. In this study three groups were formed: I, which included rats of WAG line, born to mothers with physiological pregnancy and derived from the experiment on the 1st, 14th and 35th days of postnatal ontogenesis; II, which included rats of WAG line, born to mothers with physiological pregnancy, who were exposed to high altitude hypoxia on the 1st day of postnatal ontogenesis and derived from the experiment on the 1st, 14th and 35th days of postnatal ontogenesis; III, which included rats of «Black hood» line, that developed under conditions of chronic intrauterine hypoxia due to the presence of arterial hypertension in their mothers, exposed to high altitude hypoxia on the 1st day of postnatal ontogenesis and derived from the experiment on the 1st, 14th and 35th days of postnatal ontogenesis. It was conducted the morphometrical study for determine the specific volume of the liver stroma and an immunohistochemical study using monoclonal antibodies to types I, III collagen and fibronectin.

Results: Mixed experimental hypoxia leads to increase of the specific volume of liver stroma of descendants from the 1st to the 35th days of postnatal ontogenesis due to the sclerotic changes development, which manifest by thickening of the connective tissue fibers bundles, a decrease the distance between them, the presence of places among the connective tissue fibers with only collagen fibers, activation the collagen formation processes with the predominance of the mature type I collagen over the immature type III collagen, increase fibronectin expression. Acute postnatal hypoxia does not affect the specific volume of the liver stroma of descendants from the 1st to the 35th days, however since the 14th day leads to the sclerotic changes development in this organ, which increase to the 35th day, less pronounced compared with the detected sclerotic changes in thecase of mixed hypoxia, and are characterized by the thickening of the connective tissue fibers bundles with the subsequent decrease the distance between them, the expressed predominance of collagen fibers over elastic fibers, increased fibronectin expression, activation the collagen formation processes with the predominance of the type I collagen over the type III collagen.

Conclusions: Acute postnatal hypoxia from the 14th day of postnatal life and mixed hypoxia the 1st day lead to the sclerotic changes development in the children liver, which are more pronounced in cases of mixed hypoxia modeling and increase with the age.