Effect of Various Physical Stress Models on Serum Cortisol Level in Wistar Rats

Abstract

Background: Stress indicates the response or reaction of an organism to the environmental circumstances and their outcomes. Acute stress is well known to trigger several hormonal alterations in animals. An increase in glucocorticoid concentration can represent intensity of discomfort or distress experienced by an animal. The study was undertaken to evaluate the effects of various physical stress models on serum cortisol level in Wistar male rats. Methodology: In this study six Wistar male rats weighing 150- 200 gm were randomly selected. Animals were exposed to ‘forced swim test’ and ‘restraint test’. Their serum cortisol level was measured by ELISA test using alpha prime ELISA system before and after the tests respectively. Results: Results were analyzed by students paired t-test. Serum cortisol level was significantly higher after forced swim test as well as after restraint test. When both the physical activities were compared, serum cortisol level was increased more after restraint stress than after forced swim test however, the difference was not significant statistically. Interpretation and Conclusion: The rise in serum cortisol level was observed in both the physical activity models . Rise in serum cortisol level was significantly higher after restraint test than exposing them to forced swim test. This indicates that restraining the rats produced more stress than making them forcefully swim.

Keywords

• forced swim test
• restraint test