BACKGROUND: Biological systems of all levels of organization are characterized by the rhythm of functioning processes, which are one of the fundamental properties of living matter. The complex of circadian rhythms of mammals, being genetically determined, is quite plastically modulated by the action of periodic factors of the external and internal environment. Significant factors in the disorganization of biorhythms in the modern world include a violation of the light-dark regime, so-called light pollution. Alcohol abuse remains one of the most important medical and social problems of modern society. One of the important effects of alcohol is its destructive effect on the circadian rhythms of many physiological processes. AIM: The aim of the research was to study the influence of constant lighting, chronic alcohol intoxication and joint effect of these factors on the diurnal dynamics of several biochemical parameters in Wistar rats of both sexes. MATERIALS AND METHODS: The study was conducted on 200 and 160 female outbred Wistar rats at the age of 6 months, weighing 350 15 g. Rats were divided into 8 groups. 1st group (control ♂) is kept at fixed light regime (light/dark 10:14 hours with lights on at 8:00 and off at 18:00). 2nd group, males (n = 50) is kept under the same conditions as the control, but receives a 15 % aqueous solution of ethanol ad libitum as a drink instead of water, i.e. is subjected to chronic alcohol intoxication. Group 3, males (n = 50) are kept under constant light. The 4th group, males (n = 50) are also kept under constant illumination and receive 15 % aqueous ethanol solution ad libitum as a drink. Group 5 (control ♀) females (n = 40), are kept at a fixed light regime (light/dark 10:14 am with lights on at 8:00 and off at 18:00). The 6th group, females (n = 40) are kept under the same conditions as the control, but receive 15 % aqueous ethanol solution ad libitum instead of water as a drink, i.e. subjected to chronic alcohol intoxication. Group 7, females (n = 40) are kept under constant light. The 8th group, females (n = 40) are also kept under constant light and receive 15 % aqueous ethanol solution ad libitum as a drink. In the blood samples taken at 9:00, 15:00, 21:00 and 3:00 hours the content of AST, ALT, glucose, total protein, albumin, total and direct bilirubin was measured. The reliability of circadian rhythmicity of studied parameters was assessed with use of cosinor analysis. RESULTS: It is established that the chronic alcohol intoxication, constant illumination and joint action of this factors lead to similar changes in biochemical parameters in rats of both sexes, but in female rats the level of AST, total and direct bilirubin changes as a result of three weeks of intoxication, which is not observed in males. In turn, both individual and joint effects of chronic alcohol intoxication and dark deprivation lead to significant changes in rhythmostasis in rats, however, circadian rhythms of total protein, as well as both types of bilirubin, are more resistant to dark deprivation in females than in males. CONCLUSIONS: The conducted study testifies that a three-week chronic alcohol intoxication causes more significant changes in the biochemical profile in female rats compared to males. At the same time, the studied circadian rhythms of the biochemical parameters of the organism of females turn out to be more resistant to dark deprivation than those of males, being destroyed only under the combined action of chronic alcohol intoxication and constant illumination.

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The aim of the research was to study the effect of chronic alcohol intoxication and constant il-lumination on the circadian rhythms (CR) of some parameters of the cardiovascular system in rats separately, as well as to study the rhythms of these parameters under the combined action of chronic alcohol intoxication (CAI) and constant illumination. It was found that chronic alcohol intoxication CAI at a fixed light regime causes a decrease in heart rate, an increase in SBP and PP; no changes were noted at CAI under constant lighting. At the same time, constant illumina-tion without ethanol exposure results in a decrease in heart rate and an increase in PP. At the same time, CAI with a fixed light regime leads to the destruction of CR of all parameters, except for MBP; at constant illumination with CAI no circadian rhythms of HR, DBP, PP and MBP are detected. Constant illumination leads to the destruction of the CR of PP. Among the remaining CRs, the heart rate rhythm, which is extant in the second group, persists practically unchanged, but the characteristics of all other CRs change significantly in comparison with control.

Introduction. Melanoma is one of the most malignant human tumors, originating from melanin-forming tissue. Currently, among the risk factors for the development of malignant neoplasms, including melanoma, light pollution is considered – exposure to light at night. In turn, the violation of circadian rhythm under conditions of light pollution often leads to the occurrence of desynchronosis, which is the cause of the development of a number of diseases, including malignant neoplasms. As a rule, light pollution is accompanied by a decrease in the production of epiphyseal melatonin, which has oncostatic, antitumor and antioxidant effects.The objective of study was to study the morphological features of transplanted B16 melanoma, to establish the micromorphometric indicators of tumor cells and circadian rhythms of some of them for further use as control indicators in the study of the effect of various light regimes and experimental therapy on the morphofunctional state of the body of animals with transplanted melanoma.Methods and materials. The study was conducted on male hybrid mice of the BDF1 line. The animals were divided into 2 equal groups of 25 individuals. The first group served as an intact control, the mice of the second group were transplanted with B16/F10 melanoma. On the 15th day after tumor inoculation, the animals were withdrawn from the experiment at 9.00, 15.00, 21.00 and 3. The mass and volume of the tumor were determined, microscopic, including micromorphometric studies of tumors were performed. Glucose levels were determined in blood plasma. The daily dynamics of the studied parameters was assessed, and for the statistical calculation of the amplitude and acrophase of circadian rhythms, a cosinor analysis was performed.Results. The study of the circadian rhythm of glucose made it possible to reveal its difference in animals with melanoma from that in the control. Changes in the daily rhythmicity of this metabolite, which comprehensively reflects the synchronization of many rhythms with each other, allows us to state a significant change in circadian rhythmostasis in animals with melanoma. As a result of the study, we have established micromorphometric indicators characteristic of B16 melanoma on the 14th day after transplantation. The circadian rhythm of the area of the nucleus and cells, the mitotic index and the absence of a clock for the NCR were established. The difference between the phase-amplitude features of the CR of the area of the nucleus of melanocyte cells from the normal ones was found.Conclusion. The obtained data indicate a change in rhythmostasis in mice with experimental B16 melanoma. The features of the organization of the rhythmicity of the tumor itself can be used in its targeted experimental therapy, taking into account chronobiological features. The results of the study can be used for further studies of the effect of various lighting modes on the morphofunctional state of the animal organism in the pathology under study.

Wistar rats in the reproductive period and the period of pronounced senile changes in norm and pathological conditions were studied. The same informational parameters were also determined for some non-oncological pathologies, for hepatocellular adenoma and for hepatocellular carcinoma at both ages. It is established that in ontogenesis there is an increase in the level of real structural diversity (Н) and coefficient of relative entropy of the system (h). At the same time a decrease of level of organization of system (S) and coefficient of relative organization of system (R) are noted. In the studied periods of ontogenesis, at similar pathologies and pathological processes in liver, in reproductive period of ontogenesis the organ is characterized by fewer devia-tions from the norm and higher level of adaptation and compensative abilities than in the period of pronounced senile changes. Changes in informational condition of liver at hepatitis have the same direction as ontogenetic changes. They lead to an increase in the disorder of the system and a decrease in the level of its integrity, which results in a decrease in the level of adaptive and compensatory resources. In tumors, a decrease in H and h was found with a simultaneous increase in S and R compared to age norms, which are more pronounced in malignant neoplasms. For all the studied pathologies, changes in the information state are more prominent in the liver of rats in the period of pronounced senile changes.