Evaluating the Anti-depression Effect of Xiaoyaosan on Chronically-stressed Mice

This method can help answer key questions in the field of depression, prevention and treatment using traditional Chinese medicine such as Xiaoyaosan, a widely used formula in the psychological disease for thousands of years in China. The main advantage of this technique is to provide an experimental support for the availability of Xiaoyaosan in the prevention and treatment of depression. The implications of this technique extend toward pre-clinic research on the treatment of depression because it provides a standardized protocol for sensing the anti-depressant effect using traditional Chinese medicine.

Generally, individuals new to this method will struggle because the modeling process is very complicated and the important measurement parameters for depressive behaviors is not easy to master. To induce depression, expose mice daily to any 2 of the following 7 stressors for 21 consecutive days. Note administer medicine to the mice in the two treatment groups every day before modeling and provide 0.5 milliliters of distilled water to the mice in the control and model groups.

Expose mice to food deprivation by emptying the feed of each cage. Or water deprivation by removing the water bottle for 24 hours. Expose mice to restraint stress, where the mouse is restrained in a small plastic tub for 3 hours.

Or an empty cage with the padding removed. As another option, expose mice to wet and soiled cages by pouring water into each cage and keeping wet for 24 hours. Expose mice to crowded cages in which five mice are placed in one cage for 25 hours.

For the last option, expose mice to ice cold swimming by forcing each mouse to swim in a clear glass aquarium with ice water for five minutes. Finally, record the coat state and body weight weekly until the end of modeling at day 21 and calculate the total score of the coat state. On the first two days of the sucrose preference test, house the mice individually with two bottles filled with tap water.

For the next two days, give the mice two bottles filled with 1%sucrose solution. On the last day, give the mice two bottles for 24 hours, one with tap water and the other with 1%sucrose solution. To eliminate a side preference of the mice in drinking behavior, switch the position of the two bottles after 12 hours.

Record the volume of both the consumed sucrose solution and tap water. Lastly, calculate the sucrose preference. Begin by dividing the floor of a four sided wooden black lusterless box into 25 equal squares by blue lines.

Clean the open field box with 5%alcohol prior to the access of each mouse. Then place the mouse in the center of the open field. Suspend a high definition digital camera approximately 200 centimeters right above the field and record the behavior of each mouse for 5 minutes.

Finally, evaluate and analyze the mice behavioral video by the video tracking system software and record the data of the total running distance and number of entries into the center zone. The coat state of mice was notably improved after continuous treatment with Xiaoyaosan or Fluoxetine compared to the model group. A significant reduction in body weight was manifested by the third week.

At baseline, mice in all groups had a similar sucrose preference. However, a significant drop in sucrose preference was observed after 3 weeks of stress procedure in the model group. Further, all mice exhibited a similar behavioral state before stress exposure at baseline.

However, after stress exposure for 3 weeks, the total distance moved in 5 minutes was significantly lower in the model group than the control group. The number of entries into the central zone of the model group significantly decreased as well compared with the control group. While attempting this procedure, it's important to remember to conduct this behavior test as well as administer the two medicine, 1 to 2 hours before daily modeling in order to confirm the effects by the medicine itself.

Following this procedure, other methods like forced swimming test can be performed in order to answer additional questions like can Xiaoyaosan improve the desperate behavior of depressive mice in the forced swimming test? After it is development, this technique paved the way for researchers in the exploration of the effect and underlying mechanism of Chinese medicine in the field of prevention and treatment of depression.