Involvement of free radicals in ageing: a consequence or cause of senescence.

Free oxygen radicals are increasingly discussed as important factors involved in the phenomenon of biological ageing. Higher formation rates of free radicals from senescent animals observed in isolated biological materials (mainly in mitochondria), accumulation of free radical damage and changes of antioxidant capacities appear to prove the correctness of this assumption. In the present review these findings are critically examined in order to evaluate whether free radicals do contribute to the initiation and/or propagation of ageing. It is concluded that data available so far do not allow a definite answer to this question although, free radicals are very likely to contribute considerably to the development of stochastic disorders observed during the progress of ageing.