Antioxidant system alterations and physiological characteristics of neonatal and juvenile DAT-KO rats.

Dopamine transporter knockout (DAT-KO) rats represent a valuable rodent model for studying the molecular and phenotypical outcomes of the effects of excessive dopamine accumulation in the synaptic cleft and the prolonged action of dopamine on neurons. Animals with DAT deficiency are characterized by hyperactivity, stereotypy, cognitive deficits, and impairments in behavioral and biochemical indicators. Several key pathophysiological mechanisms are known to be common to psychiatric, neurodegenerative, metabolic, and other diseases. Among these mechanisms, oxidative stress systems play a particularly important role. One of the main antioxidant systems in the brain is glutathione: specifically, glutathione S-transferase, glutathione reductase, and catalase play a significant role in the regulation of vital oxidative processes, and their dysfunction has been shown in Parkinson's disease, Alzheimer's disease, and other neurodegenerative diseases. The current study aimed to analyze the dynamics of the activity levels of glutathione reductase and glutathione S-transferase in erythrocytes, as well as catalase in the blood plasma, of DAT-deficient, homo- and heterozygous, neonatal and juvenile rats (both male and female). Their behavioral and physiological parameters were evaluated at the age of 1.5 months. For the first time, changes in physiological and biochemical parameters were shown in DAT-KO rats at 1.5 months of postnatal life. The key role of glutathione S-transferase, glutathione reductase, and catalase in the regulation of oxidative stress in DAT-KO rats at the 5th week of life was demonstrated. A positive effect of a slightly increased dopamine level on memory function was shown in DAT-heterozygous animals.

Structural uterine changes in postpartum endometritis in cows.

AIM: The purpose of this work was to study the dynamics of structural manifestations of acute cases of postpartum endometritis in cows. MATERIALS AND METHODS: The light and electron microscopy methods were used when studying structural changes in the endometrium in case of postpartum endometritis in seven cows. Sections of endometrial specimens for light microscopy, 5-7 µm thick, were stained with hematoxylin and eosin and also by Van Gieson's. For electron microscopy, semi-thin sections were stained with Azur-2 in combination with basic fuchsin, as well as contrasting by lead citrate and uranyl acetate. RESULTS: As a result of the study, we have established the following: Necrobiosis of the epithelial layer of the mucosa, cellular infiltration with shaped elements of blood in the functional layer, swelling of the cells of the uterine gland, and single microbial cells on the surface of the mucosa. We have noted edema of the stroma of the functional layer of the endometrium, swelling of the epithelial layer of the endometrial mucosa, and swelling of fibroblastic and lymphoid cells. Ultrastructural changes in endometrial cells in case of acute postpartum endometritis in cows are accompanied by the destruction of microvilli on the apical surface of the epithelium, an abundance of coccal microflora on the surface of the epithelium, necrobiosis of epithelial cells, and partial edema of the nucleus, and cytoplasm of the histiocyte. CONCLUSION: We had established that acute purulent-catarrhal dystrophic processes were observed in the structural organization of the endometrium. In the depth of catarrhal mucus on the surface of the endometrium, there was an abundance of bacterial flora, with diplococci being prevalent. In ultrastructural organization of the endometrium, we observed deep dystrophic and necrobiotic processes in the parenchyma and endometrial stroma, as well as exudative processes with a change in the integrity of the microcirculatory bed. Thus, to prevent an inflammatory process from turning into a latent form, it is necessary to detect acute postpartum endometritis promptly using diagnostic methods taking into account the obtained parameters of the dynamics of structural changes in the uterine tissues.