【Animal modeling】-Effect of natural enemy sound stress on anxiety-like behavior in SD rats

  Objective: To observe the effects of natural enemy sounds on anxiety-like behaviors of SD rats under different durations and repeated stress.

  Methods: The behavioral changes of rats in open field test (OFT) and elevated plus maze (EPM) were observed after single or repeated natural enemy sound stress. The average velocity of OFT and EPM was used as an indicator of the rat's overall activity level, and the distance ratio and dwell time ratio of OFT central area and EPM open and closed area were used to evaluate the rat's anxiety state. Results Before a single stress, the overall activity level of the rats in each group was the same, and they were in a low anxiety state; on the 1st (OFT), 3 (OFT) and 7 days (EPM) after stress, compared with the blank control group, the rats were in a state of low anxiety. Both 10min and 60min single natural enemy sound stress could significantly reduce the ratio of distance and duration of stay in central OFT or EPM open-arm zone (P<0.01). On the 1st (EPM), 3 (OFT) and 7th day (EPM) after repeated natural enemy sound stress, the proportion of distance traveled and the proportion of residence time in the central area of the OFT or the open arm area of the EPM were significantly decreased compared with the blank control group ( At the same time, on the 7th day after repeated stress, diazepam (1mg/kg, i.p.) could effectively reverse this anxiety state level in rats with natural enemy sound stress (P<0.01).

  Conclusion: Natural enemy sound stress can increase the anxiety-like behavior in rats, and a single natural enemy sound stress takes effect in a relatively short period of time (10 min), the effect lasts (no less than 7 days), and repeated stress is not tolerated.