CHANGES OF SUBCIRCADIAN RHYTHMS OF INDICATORS OF THE PROOXIDANT AND ANTIOXIDANT DEFENSE SYSTEM IN THE KIDNEY OF RATS WITH TETRACHLOROMETHANE INTOXICATION AND CORRECTION OF MELATONIN

Abstract

The subcircandian rhythms of TBA-reactive products content, aldehyde and ketone derivatives of DNFH, the activity of catalase in rat kidneys with tetrachloromethane intoxication on the conditions of experimental equality have been investigated. It was shown that intoxication with tetrachloromethane causes desynchronization of circadian rhythms of the studied indices. Five-single administration to intoxicated animals of melatonin on the conditions of experimental equality leads to the restoration of rhythms and the correction of absolute values of the investigated variables.The aim of the study. To investigate the effect of melatonin on subcircadian rhythms of free radical oxidation indicators in rat kidneys with tetrachloromethane intoxication on the conditions of experimental equality.Materials and methods. Research conducted on white nonlinear sexually mature male rats weighing 180 ± 10 g, which were kept under vivarium conditions with constant temperature (+200С) regime and artificial lighting with an intensity of 1500 lux in a mode of 12 hours of light up to 12 hours of darkness (12L:12D) throughout the experiment. After a 7-day simulation of light conditions the animals were separated into groups: 1st group – a control group of animals (intact animals); 2nd group – animals that were intradermally administered of melatonin solution; 3rd group – animals that were intragastric administered twice of tetrachloromethane solution; 4th group – intoxicated tetrachloromethane animals were intragastric administered of melatonin solution. Euthanasia of animals was carried out by decapitation under a light etheric anesthesia at 8.00, 12.00, 16.00 and at 20.00 o’clock. In the post-nuclear supernatants of the 5%-s kidney homogenates were determined: the content of TBA-reactive products, aldehyde and ketone derivatives of DNFH, catalase activity. The received digital data was processed statistically by the method of variation statistics using Student's t-test.Results. The state of free radical oxidation of lipids and proteins in rat kidneys under artificial lighting with an intensity of 1500 lux from 8.00 to 20.00 hr fluctuated within one indicator with an average value for the content of the TBA-reactive products – 41,1±1,59 µmol/g of tissue and for the content of the aldehyde and ketone derivatives of DNFH – 24,6±1,23 oz/g of tissue. Poisoning of animals with tetrachloromethane leads to increased oxidation of lipids and proteins in the ratkidneys at 16.00 h – forming a subcircadian rhythms with a pronounced maximum. Administration of melatonin to rats affected by tetrachloromethane on the conditions of experimental equality has led to a decrease in the absolute values of the content of free radical oxidation products of lipids and proteins in the kidney of animals during the day and has led to the restoration of the structure of subcircadian rhythms of the corresponding indices. The catalase (CAT) activity on the conditions of experimental equality acquired maximum values at 20.00 h (20,9±0,45 μmol/min/g of tissue), and the minimum – 19,9±0,52 μmol/min/g of tissue was at 8.00 and 16.00 h. In the conditions of toxic lesions with tetrachloromethane a sharp decrease on average by 45% in the activity of catalase was observed. The administration of melatonin resulted in an increase in the absolute values of activity of catalase in rat kidneys in comparison with the indicators of a group of animals which were intoxicated with CCl4 on average by 30%.Conclusions. 1. On the conditions of experimental equality under the artificial lighting with an intensity of 1500 lux subcircadian rhythms of the main indicators of pro- / antioxidant protection during light day in the rat kidneys have a small amplitude of oscillations. 2. Inoxication of rats with tetrachloromethane caused desinchrosis of indicators of free radical oxidation of macromolecules in the kidneys. 3. Five-single administration of melatonin has led to the restoration of the subcircadian rhythms of the investigated indicators.