Effect of time course of foot shock stress on anxiety-like behavior in rats ã€Abstract】Objective: To observe the influence of the time course of foot shock stress on the anxiety of the rat in the elevated plus maze and the experimental opening behavior. Methods Adult male Sprague-Dawley rats were randomly divided into control group and plantar shock group according to body weight stratification, with 12 rats in each group. The plantar shock group was given an inescapable foot shock (0. 8 mA, electric shock 10 s, rest 20 s, 5 min 1 time/d). The elevated cross maze and the opening experiment were measured after 7 d and 14 d of the foot electric shock respectively to evaluate the anxiety behavior of the rats. Results After 7d and 14d foot shock, the anxiety-like behavior of the foot-shock group increased, the difference was significant (p<0.01). The total number of in-arms was significantly lower than that of the control group, and the exercise activity decreased. In the opening experiment, the number of times the foot shock group entered the central area and the stay time in the central area was lower than that of the control group (P<0.01). The total distance of exercise, the number of uprights and the number of grooming were significantly lower than those of the control group (P<0. 01), the activity of exercise exploration is reduced. Comparing the behavioral results of the 7-day and 14-day foot shock groups, it can be seen that with the increase of modeling days, the ratio of closed-arm time to closed-arm time in rats showed a downward trend (P<0.05), and the degree of anxiety decreased. The total distance, number of uprights and number of grooming in the opening experiment were lower than 7d for 14 days, and the difference was significant (P < 0.05), suggesting that the motor exploration behavior was further reduced, the self-attention decreased, and the depression-like behavior increased. Conclusion The foot shock stress of different time courses leads to anxiety-like behavior in rats, which affects the activity of rat exploration. With the increase of modeling days, the behavior of rats may change from anxiety to depression. The time course of the model of the electric shock stress anxiety model was better than 7 days. Anxiety disorders are very common in today's society, with a slow course of disease, associated with many negative outcomes, such as greater risk of suicide, combined with medical conditions, and a low rate of remission with depression. The study of anxiety disorders requires the support of animal models. Although the anxiety-like behavior of rodents differs from the definition of human clinical anxiety, the similar affected brain regions and the improvement of rodent behavior in human anti-anxiety drugs suggest that the study of rodent anxiety-like behavior can be applied to humans. The study of anxiety issues provides clues that stress plays an important role in many pathophysiological processes associated with neurodegenerative diseases and mental illness. Excessive stress response is associated with anxiety. Studies have shown that short-term chronic stress can lead to anxiety-like behavior in rats. Foot shock stress is one of the classic stress patterns and is widely used in conditional fear related research. Anxiety and fear are closely related. Many studies have used animal models of anxiety and depression to make inevitable foot shock stress. However, there is currently no research on the effects of different time course of foot shock stress on anxiety-like behavior in rats. We observed the effects of different degrees of chronic stress stimulation on the anxiety of the rats in the elevated plus maze and the opening experiment after the different time courses of adult SD rats. The purpose was to find the most model of the foot shock anxiety model. The best modeling time node provides an experimental basis for studying typical anxiety-like behaviors. 1 Materials and methods 1. 1 material 1. 1. 1 animals and grouping Twenty-four SPF SD male rats weighing 200-220 g, 6 weeks old, were provided by Shanghai Experimental Animal Resource Center (Beikai, Xipuer). The animals were kept in rat ventilated cages, the ambient temperature was controlled at 21 to 23 degrees, the humidity was about 50%, and the water was free. The experiment was conducted in the Experimental Animal Center of Nanjing University of Traditional Chinese Medicine. The disposal of animals during the experiment strictly abides by the "Guiding Opinions on Treating Experimental Animals" promulgated by the Ministry of Science and Technology of China in 2006. After one week of animal adaptation, the animals were randomly divided into control group (12 groups) and foot shock group (FS, 12). 1. 1. 2 instruments and equipment Experimental equipment: foot electric shock box (Shanghai Xinsoft Information Technology Co., Ltd.); rat ventilation rat cage (Shanghai Xinsoft Information Technology Co., Ltd.); Supermaze animal behavior analysis software (Shanghai Xinsoft Information Technology Co., Ltd.) 1. 2 methods 1. 2. 1 experimental plan In order to avoid the emotional state of the rat's breath communication, the foot shock group of this experiment was isolated, and the rat ventilated cage device can avoid the exchange of breath between rats. The control group was raised and strobed for a few minutes each day, leaving no treatment. The foot shock group received a foot electric shock every day. The electric shock parameters were: 0. 8 mA, electric shock for 10 s, and body weight for 20 s for 5 min. After 7 days and 14 days of foot shock, the elevated cross test (10:00 to 42:30) and the opening experiment (14:00 to 15:00) were used to evaluate the anxiety behavior of the rats. 1.2.2 elevated fever experiment The Elevated plus maze } EPM device (Supermaze Animal Behavior Analysis Software) consists of two opposite open arms (50 cm x 10 cm) and two opposite closed arms (50 cm x 10 cm x 40 cm) and central The area (10 cm x 10 cm) is connected and is 50 cm from the ground. Before the experiment, the rats were moved to the laboratory to adapt to the environment for more than 1 h, keeping the room quiet and dark. At the beginning of the experiment, the rats were placed in the maze from the central grid facing the closed arm, and the activity within 5 min was recorded. The number of times the rats entered the open arms and the closed arms and the residence time were observed. Each rat was removed after the end of the experiment, the arms were cleaned and the odor was removed with 75% alcohol. Behavioral results (1) Closed arm time ratio = closed arm time / (open arm time + closed arm time); (2) closed arm times ratio = number of closed arms / (number of open arms + number of closed arms). (3) Total number of arms entering = number of closed arms + number of open arms. The behavioral results were excluded from the outliers using the SPSS software box plot method. 1.2.3 Opening experiment The open box length x width x height of the experiment is: 100 cm x 100 cm x 40 cm, the inner surface and the bottom surface are all blue, and the camera is placed directly above the central area. On the 8th day and the 15th day of the experiment, each group of rats was subjected to the open field experiment. The animals were moved into the test room 1 hour before the experiment to adapt to the environment. After the experiment was started, the rats were placed in the fixed position in the central area, and the head was placed each time. The part is fixed to one side. Each rat measured 5 min measurement indicators including total exercise distance, central zone dwell time, central zone entry times, erect times and grooming times, followed by 75% alcohol to clean the inside of the box, and then the alcohol was volatilized and tasteless. 1. 2 results 2. 1 Comparison of behavioral results of elevated cross maze The ratio of the number of closed arms and the time of the closed arm of the foot shock group were significantly higher than those of the control group. The total number of arms into the arm was lower than that of the control group (P<0.01), indicating that the anesthesia-like behavior of the rats caused by the foot shock caused the motor activity of the rats. decline. When compared with 7d, the 14-day closed-arm ratio and the closed-arm time of the foot-shock group were lower than those of the 7-day (P < 0.05), and there was no difference between the two points in the control group. 2. 2 opening behavioral results Compared with the control group, the number of entrances in the central area, the length of stay in the central area and the total distance of exercise were significantly lower than those in the control group (P < 0.01, P < 0.05). Compared with 7d of foot electric shock, the total distance of motion decreased further, and the number of erecting and grooming times of rats decreased significantly (P < 0.05), while the residence time of central area and the number of entry times were between two electric shock days. The difference is not big. In the control group at two time points, except for the number of grooming, there was no significant difference in the behavioral behaviors of the other openings. 3 discussion There are many modeling methods for how to establish a reasonable animal model of anxiety, including: elevated plus maze, empty bottle stimulation, natural enemy exposure, drinking water conflict, etc., but there are still many uncertain factors and interference factors. Stress is an important foundation of mental illness and is closely related to anxiety and depression. The chronic stress anxiety model can be used as a model of anxiety. In summary, the combination of foot electric shock and orphan can cause anxiety-like behavior in rats, which can be used as a model of chronic stress anxiety. The degree of anxiety in the 14 d rats decreased compared with that in the 7 d. However, the activity and self-attention of the rats were further reduced, and the depression-like behavior was increased. It can be considered that the selection of the time course of the model of the foot shock stress anxiety model is better than that of 14d. Our experimental results further support the view that stress duration affects the anxiety and depression-like behavior of animals from the perspective of behavior. The study of stress-related mental illness should pay attention to the time course, intensity and type of stress of stress, which is related to the clinical situation. Closer, and the mechanisms behind the impact of time is still in need of further study. Soft Bandages,Cotton Bandages,Medical Bandages,First-Aid Plaste Bandage Zhende Medical Co.,Ltd , https://www.zdmedicalproducts.com