The effect of hypochlorous acid inhalation on the activity of antioxidant system enzymes in rats of different ages.

Hypochlorous acid HOCl is an effective disinfectant with a broad spectrum and high rate of microbicidal action. Its use for air treatment can be an effective tool for the prevention and therapy of infectious diseases. In this work, the in vivo study was conducted on 110 Wistar Han rats (12 and 72 weeks old) on the effect of a single inhalation of air containing gaseous HOCl on the activity of antioxidant system enzymes. For this, a special installation was designed to uniformly maintain the concentration of HOCl in the air and regulate it over a wide range. Inhalation exposure was carried out for 4 h at total chlorine concentrations in the air of approximately 2.0 mg/m³ and 5.0 mg/m³, after which the animals were observed for 14 days. The effect of inhalation on the antioxidant system activity varied significantly in animals of different ages. Catalase activity in young rats increased approximately 2-fold on days 1-2 after inhalation, regardless of the HOCl concentration, while in old animals a sharp dose-dependent decrease was initially observed. The glutathione peroxidase activity in animals of both ages increased upon inhalation of air with 5.0 mg/m³ HOCl, and in old animals this was more pronounced; when the HOCl concentration decreased to 2.0 mg/m³, this indicator increased slightly in old rats and remained virtually unchanged in young ones. The glutathione reductase activity when exposed to 2.0 mg/m³ HOCl did not change for both age groups, and with increasing HOCl concentration it increased by 1.5-2.0 times in all animals.