ADAPTATION TO THE INFLUENCE OF VARIOUS FACTORS ON BODY MASS AND THE CONDITION OF THE PANCREAS IN RATS

ISSN: 2582-4686 SJIF 2021-3.261,SJIF 20222.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 569 ADAPTATION TO THE INFLUENCE OF VARIOUS FACTORS ON BODY MASS AND THE CONDITION OF THE PANCREAS IN RATS Mirzarakhimova Marina Anvarzhanovna (PhD), Associate Professor of the Department of Normal Physiology Andijan State Medical Institute, Republic of Uzbekistan, Andijan E-mail: [email protected] ABSTRACT Changes in the body mass of rats and the mass of their pancreas can vary greatly depending on different factors. Environmental conditions, nutrition, and activity levels play a significant role in this process. Rats are capable of adapting to changing circumstances, which allows them to maintain optimal bodily functions. The effects of stress, temperature, and available resources can lead to changes both in body weight and in pancreatic function. These adaptive mechanisms help rats survive in diverse ecosystems and under changing conditions. Studying these processes provides important insights into the physiology and ecology of these animals, as well as how they respond to challenges and adapt to them. Ultimately, adaptation to various conditions is a key aspect that directly affects the health and survival of rats. Keywords: hypokinesia, pancreas, rats, external temperature, insolation, adaptation. Motor activity - is a fundamental property of both animals and humans and is an essential part of life and the development of every organism. Over the course of life, due to various environmental demands, the level of motor activity often changes, either increasing or decreasing. When a person’s lifestyle changes and motor activity necessarily increases, the body must adapt to this new state (e.g., heavy physical labor, regular sports training, etc.). In such cases, a specific adaptation develops, involving structural changes in muscle tissue—more precisely, an increase in its mass to meet enhanced functional demands [6]. This mechanism is based on the activation of muscle protein synthesis. F.Z. Meerson described a pattern between organ function and the genetic apparatus of the cells composing the organ. Increased function per unit mass of tissue leads to changes in the activity of the genetic machinery: the amount of messenger RNA (mRNA) increases, which leads to an increase in ribosomes and polysomes where protein synthesis occurs. As a result, the volume and quantity of cellular proteins increase, muscle mass grows, and hypertrophy occurs. At the same time, in the mitochondria of muscle cells, pyruvate utilization increases, preventing lactic acid buildup in the blood and promoting the mobilization and use of fatty acids. This, in turn, improves work capacity [1,2,3,6]. Consequently, the volume of function matches the structural volume of the organ, and the organism becomes adapted to the imposed workload. If a person undergoes excessive training beyond physiological limits, the muscle structure undergoes significant changes. The volume of muscle fibers increases to the extent that the blood supply becomes inadequate, leading to weakened muscle energetics (as seen in some cases of bodybuilding). This phenomenon is considered maladaptation. In general, appropriately dosed physical loads increase the nonspecific resistance to various ISSN: 2582-4686 SJIF 2021-3.261,SJIF 20222.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 570 environmental factors [4,7,8]. In addition to increased activity, both humans and animals may be forced to adapt to reduced motor activity, i.e., hypokinesia, and to various environmental factors affecting the pancreas of rats. Our aim was to study changes in body mass and pancreatic mass of rats under hypokinesia, high temperature, and solar radiation (insolation). Experimental methodology. The experiments were conducted on 100 male outbred rats weighing 150–200 g. Experiments were carried out during different seasons, when ambient temperatures varied significantly. Hypokinesia was induced by placing the rats in special cages that limited motor activity for various durations. In summer, the effects of high temperature and solar radiation were studied. The rats were exposed to sunlight on an open platform daily at 12 p.m. for 30 minutes. They received a mixed protein-carbohydrate diet, and water was always available. Before dissection, rats were anesthetized and euthanized by decapitation. The pancreas was extracted and weighed before and after exposure to hypokinesia, heat, and insolation. Results and Discussion. When hypokinesia was the sole factor, body mass changes depended on its duration. No difference was observed in body mass between the control and experimental groups during hypokinesia periods of 1 hour to 7 days. With longer durations (10, 15, and 20 days), body mass increased significantly in both groups compared to baseline, likely due to normal growth and development. As the duration of physical activity restriction in experimental rats exceeded 25 days (1, 2, 3, and 4 months), the results showed only minor differences compared to those observed after 10, 15, and 20 days of reduced physical activity. Changes in body weight between the control and experimental groups during hypokinesia lasting more than 25 days were not uniform. In both groups, the body weight of rats increased compared to the initial period. However, the body weight of rats in the experimental group was significantly lower than that in the control group. In other words, growth and development in the experimental group were markedly delayed compared to the control group. Under the combined effects of reduced physical activity, high temperature, and solar radiation, the body mass of the experimental group remained at baseline levels for one month, while the control group showed stable increases within 15 days. In other words, the combined stressors suppressed protein synthesis and enhanced its breakdown. We also studied changes in pancreatic mass under the influence of hypokinesia alone, and in combination with heat and solar radiation. Changes in the mass of the pancreas depend on the duration of hypokinesia. When the duration of hypokinesia is up to 20 days, the pancreatic mass remains at the level of the control values. As the period of reduced locomotor activity increases (25 days; 1, 2, 3, and 4 months), the pancreatic mass in the experimental group decreases significantly more than in the control group. The combined effect of hypokinesia, elevated temperature, and solar radiation causes a much more rapid decrease in pancreatic mass compared to hypokinesia alone. Under the influence of all three factors, a reduction in pancreatic mass in experimental animals is observed as early as the 5th day. Similar changes are observed with longer exposure durations. ISSN: 2582-4686 SJIF 2021-3.261,SJIF 20222.889, 2024-6.875 ResearchBib IF: 9.948 / 2024 VOLUME-5, ISSUE-12 571 Long-term reductions in muscular activity lead to decreased energy expenditure, muscle bioenergetics, and structural metabolic capacity, resulting in signs of dystrophy and degradation [1,2,4,5]. To date, both direct and indirect evidence in animals and humans shows that hypokinesia lowers tissue protein synthesis rates and increases protein breakdown. A shift in energy metabolism from predominantly carbohydrate-based to fat-based is a hallmark of stress reactions to extreme factors. One of the main causes of this shift is significant structural alteration in mitochondria in various tissues (e.g., liver, heart, skeletal muscle), weakening respiratory energy regulation and reducing ATP synthesis due to impaired oxidative phosphorylation. This results in “detraining” of the body’s primary energy system [2,7,8,9]. Consequently: 1. Periods of reduced locomotor activity led to increased body mass due to growth. However, in experimental groups with long-term hypokinesia (25 days to 4 months), growth and development lagged behind the control group. 2. Under combined influence of hypokinesia, high temperature, and solar radiation, rat growth halted, and body mass remained at baseline levels. 3. Changes in pancreatic mass depended on the complexity of environmental impact and whether hypokinesia was isolated or combined with heat and insolation. With prolonged hypokinesia (25 days to 4 months), pancreatic mass decreased. 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