A comparison between chronic exercise training and desipramine as treatments for the depression-like behavior of early-life maternal deprivation rats

We have established a depression-like behavioral animal model through maternal deprivation in rats during early life. By using this model, the curative effects of exercise training and desipramine, a tricyclic antidepressant, on the improvement of depression-like behavior in rats were compared. Four-week-old male maternal deprivation (MDP) or normal rats were divided into control and exercise groups. The exercise group animals were subjected to a protocol of running on a treadmill at a moderate intensity for 60 min/day, 5 days/week, for 5 weeks. Forced swimming and light/dark box tests were conducted here to identify the behavioral characters. In addition, the short treadmill test was also used to clarify their movement motivation. Our data showed that the immobility during the forced swimming test and retention time spent in the light box of MDP rats were significantly longer than those for the control group. However, there was no difference between MDP and normal rats in the short treadmill test. MDP rats subjected to the 3-week exercise training course could produce less immobility in the forced swimming test and less retention in the light box. However, with the long-term desipramine HCl treatment (21 days, 10 mg/kg, i.p.), MDP rats could express less immobility in the forced swimming test, but more immotility in the short treadmill test. These results suggested that exercise training and desipramine may mediate different mechanisms to ameliorate depression-like behavior in MDP rats.