Enhanced luminescence study of liver homogenate response to oxidative stress

An enhanced luminescence technique was used to monitor the response of liver homogenates stressed with sodium perborate. Rat liver homogenates were subjected to oxidative stress with sodium perborate, and the light signals, generated by a suitable system, containing luminol and compounds producing enhancement of light emission such as sodium benzoate and indophenol, were detected by a luminometer. The intensity of light emission (E) was found dependent on homogenate concentration (C). When C increased, E at first increased as well and, then, decreased rapidly. The graphic expression of this phenomenon resulted as a curve that can be described by the equation: E = a.C/exp(b.C). It is proposed that the a value represents the capacity of the tissue to catalyze the production of .OH radical species. The b value might be related to the capacity of the tissue to scavenge such radicals, since it increases when homogenates are supplemented with antioxidants and decreases when homogenates are treated with prooxidant. The results obtained by supplementing homogenates with iron containing substances, or using model systems, suggest that cell substances catalyzing the luminescent reaction, such as the hemoproteins, are "scavengers" as well as radical producers. The concentration-emission curve obtained with suitable model system is described by the equation: E = a.C/exp(b.Ck). It is suggested that, using the k value, information can be obtained on the relative capacity of hemoproteins and antioxidant systems to interact with .OH radicals.