Free radical scavengers & lipid peroxidation in acute aluminium phosphide poisoning

Free radicals scavengers superoxide dismuatase (SOD) and catalase and lipid peroxidation were studied in 45 patients of aluminium phosphide poisoning irrespective of age and sex admitted to a hospital in north India during the January 1992 to December 1993. Serial serum superoxide dismutase (SOD), catalase and MDA (malonyldialdehyde) were estimated on days 1, 2 and 5 post-admission depending on the survival of the patients. Serum SOD levels were significantly higher (P < 0.001) but serum catalase was significantly lower (P < 0.001) in patients than controls (patients of peripheral circulatory failure and normals) on days 1 and 2 which suggested stimulation of SOD and inhibition of catalase by phosphine resulting in excessive hydrogen peroxide (H2O2) load. Significantly higher levels of MDA (P < 0.001) in patients than controls on days 1 and 2 indicated enhanced lipid peroxidation in this poisoning. Twenty four patients died constituting a mortality rate of 53.3 per cent. The significantly high levels of SOD and MDA in non-survivors suggested their direct relation to mortality while catalase levels had an inverse relationship. Return of SOD and catalase and MDA to normal or near normal levels in survivors by day 5 suggested abolition of an oxidative stress due to elimination of phosphine.