Increased calcium-independent phospholipase A2 activity in vitamin E and selenium-deficient rat lung, liver, and spleen cytosol is time-dependent and reversible

Long-Evans hooded rats maintained on vitamin E and selenium-deficient diets for 6 weeks from weaning exhibited a pattern of enhancement of calcium-independent phospholipase A2 activity in spleen cytosol similar to that previously reported for the lung and liver. The spleen cytosols from vitamin E and selenium deficient rats had approximately 5 fold higher activity than the samples from animals maintained on diets sufficient in these two nutrients (control) or deficient in either nutrient alone. The calcium-dependent PLA2 activity was about 6 fold higher in spleen cytosol of vitamin E and selenium deficient rats compared with cytosolic samples from animals on the other three diets. Time course studies indicated that in rats the calcium-independent phospholipase A2 activity in lung, liver, and spleen increased initially between 4 and 6 weeks of consuming the diets deficient in both vitamin E and selenium, and increased even further again at 7 weeks. This bi-phasic response to the deficiency occurred 1 week after indicators of vitamin E and Se status had reached minimum levels. When animals that were maintained on the deficient diet for 6 weeks consumed the control diet for 1 week the phospholipase A2 activity of lung, liver, and spleen was not different than the activity of the control animals. The malondialdehyde concentration of lung and spleen measured at 6 and 7 weeks correlated positively with the calcium-independent phospholipase A2 activity. These results indicate that deficiency of vitamin E and selenium in the rat leads to a bi-phasic increase in calcium-independent PLA2 activity in rat lung, liver, and spleen, and that the initial increase can be reversed by partial repletion of the two antioxidant nutrients.