EFFECT OF CONSTANT DARKNESS AND LUZINDOLE ON VITAMINS A AND E IN YOUNG AND OLD RATS

Abstract

The study investigated the effect of constant darkness and the melatonin receptor antagonist luzindol on the vitamins A and E content in the organs of young and old Wistar rats. Two groups of rats from the age of 4 months were kept in standard lighting conditions (12 hours of light/12 hours of darkness; LD) or in constant darkness (DD). At 5 months, the rats of each group were divided into two subgroups: one received luzindol (LD+luz, DD+luz) with drinking water at a dose of 0.22 mg/kg of weight, the other group – placebo. At 6 months, some of the animals were removed from the experiment, and the remaining ones were kept in appropriate conditions until the 24 months age. The vitamins content was determined in the heart and skeletal muscles, liver and kidneys by HPLC. The results of the experiments showed that the effect of luzindol in the dark and under standard lighting had different directions. In the liver, heart and skeletal muscles of rats, an age-related increase in the vitamin A content was revealed in both light conditions. The vitamin E level in the organs of old rats compared to young changed slightly under standard lighting. Significant changes in the vitamins A and E contents were found in the heart and skeletal muscle tissues, the liver was least affected by darkness and luzindol. Under conditions of light deprivation, luzindol led to more pronounced changes in the vitamins level in old rats. Violation of the light rhythm caused changes in the level of vitamins A and E, the severity of which depended on the type of tissue, the age of the animals and the duration of exposure. In the tissues of rats kept in different light conditions, tissue-specific changes in the vitamins content were found, which were most clearly manifested in old animals.