A course of dihydroquercetin (antioxidant) injections to 5-month-old Wistar rats with sulpiride-induced benign prostatic hyperplasia led to reduction of proliferative activity in the glandular structures and to attenuation of the inflammatory reaction in the tissue. Prostatic antioxidant/prooxidant balance returned to normal after the treatment.

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The study was performed with male Wistar rats who individually received nano (NPs) or fine (FPs) titanium dioxide (TiO2) particles with an attractive food for 7 days. Two doses of TiO2 NPs (200 and 400 mg/kg) and one dose of TiO2 FPs (200 mg/kg) were used. The macroscopic status of the gastric mucosa as well as the pro-and antioxidant activity of the adherent mucus layer were examined. Our experiments showed that a chronic (7-day) oral administration of TiO2 nanoor microparticles increased the area of erosive lesions and the amount of mucosal hemorrhages with respect to control. However, the damage mechanisms in the group “TiO2 FPs 200 mg/kg” were different from those in the groups “TiO2 NPs 200 mg/kg” and “TiO2 NPs 400 mg/kg”. The oxidative damage of glycoproteins occurred in the gastric mucus of animals who received TiO2 NPs; this led to degradation of the adherent mucus layer and deterioration of its protective properties. Therewith, a dose-dependent reaction was not observed at the indicated doses of TiO2 NPs. The oxidative damage of glycoproteins was not found in the gastric mucus of animals who received TiO2 FPs; erosive lesions and mucosal hemorrhages could be induced by TiO2 FPs as the mechanical and chemical agent that does not provoke oxidative stress at the indicated dose. Our study demonstrated that the use of TiO2 in any form for increasing the attractivity of foodstuffs can be harmful for the digestive tract.

The Morris water maze (MWM) is a tool for assessment of age-related modulations spatial learning and memory in laboratory rats. In our work was investigated the age-related decline of MWM performance in 11-month-old rats and the effect exerted by training in the MWM on the redox mechanisms in rat brain parts. Young adult (3-month-old) and aged (11-month-old) male rats were trained in the MWM. Intact animals of the corresponding age were used as the reference groups. The level of pro- and antioxidant capacity in brain tissue homogenates was assessed using the chemiluminescence method. A reduced performance in the MWM test was found in 11-month-old rats: at the first day of training they showed only 30% of successful MWM trials. However, at the last training day the percentage of successful trials was equal for young adult and aged animals. This indicates that the aged 11-month-old rats can successfully learn in MWM. Therewith, the MWM spatial learning procedure itself produces changes in different processes of redox homeostasis in 11-month-old and 3-month-old rats as compared to intact animals. Young adult rats showed a decrease in prooxidant capacity in all brain parts, while 11-month-old rats demonstrated an increase in antioxidant capacity in the olfactory bulb, pons + medulla oblongata and frontal lobe cortex. Hence, the MWM procedure activates the mechanisms that restrict the oxidative stress in brain parts. The obtained results may be an argument for further development of the animal training procedures aimed to activate the mechanisms that can prevent the age-related deterioration of performance in the learning test. This may be useful not only for the development of training procedures applicable to human patients with age-related cognitive impairments, but also for their rehabilitation.

The mucus layer covers all the internal surfaces of the body. The surfaces communicate with the external environment. The functions of the mucus layer are determined by its components, including glycoproteins that provide physical and chemical protection to the epithelium. The glycoproteins also perform the exchange function with the external environment. Even at the dawn of evolution, glycoproteins were exteriorly organized to protect the first multicellular animals from external microorganisms, pathogens, and toxins. It is interesting to note that the structure of the glycoproteins has similarities with the structure of antibodies, especially in terms of the relatively constant polypeptide chain and its glycosylated sections, containing oligosaccharide chains with different variants of monosaccharides. The review discusses modern concepts of the mucus layer evolution, the structure of glycoproteins, the peculiarities of its synthesis, degradation, and under-researched functions of the mucus layer. It is assumed that the mucus layer has virucidal and bactericidal capabilities due to circulating enzymes of the digestive tract, which can accumulate in the mucus layer and degrade any microorganisms, regardless of their variation, mutations, and recombination. Therefore, the normal production of digestive tract enzymes can provide non-specific protection from external pathogens entering through open systems of the body. Understanding these processes can significantly limit the spread of existing and new infections.