Background: 

The beneficial effects of regular physical exercise and its effectiveness in the prevention of several chronic diseases and premature death have been studied. However the molecular mechanisms associated to this prevention have not been completely determined.

Aim: 

The aim of our study was (i) to determine the effect of 8 weeks of aerobic exercise training on the survival of a group of rats treated with a lethal dose of paraquat (ii) to study the effect of 8 weeks of aerobic exercise training on the expression of p53.

Methods: 

For the paraquat experiments 16 four-month-old male Wistar rats were randomly divided into 2 groups, exercise group (n=8) and a sedentary group (n=8). Endurance-trained animals were exercised 5 d/wk during 8 wks on an animal treadmill at an intensity of 75%VO₂max. After this period, all animals received an intraperitoneal injection of paraquat (35 mg.kg^-1). Sa0₂was measured every four hours and a survival curve was performed.

For the p53 expression experiments 10 four-month-old male Wistar rats were randomly divided into 2 groups, exercise group (n=5) and a sedentary group (n=5).

Results: 

Results indicate that moderate aerobic exercise significantly protects against paraquat induced toxicity. We also found a systemic training-induced over-expression of p53 in lung, liver and kidney but not in heart

Conclusions: 

Our results show that aerobic exercise training protects against paraquat induced mortality. Exercise induced over expression of p53 could, at least in part, explain the beneficial effect of this type of exercise in our experimental model.

The authors' work was supported by grants BFU2007-65 803/BFI, 35/UPB20/08 and ISCIII2006-RED13-027.