Phospholipase A(2) activity, heat shock protein, and superoxide dismutase in rat remnant kidney

Male Sprague-Dawley rats (150-200 g) were randomly assigned to sham operati on (n=6) or 5/6 nephrectomy (n=12) procedures. Two weeks after the completi on of the 5/6 nephrectomy, these animals were again randomly assigned to tw o groups: non-treatment or treatment with vitamin E supplementation at 200 IU/kg chow. Two weeks later. all animals were sacrificed and the kidneys ha rvested. The secretory phospholipase A? (PLA,) activity was elevated (150%) in the untreated remnant kidney but returned to sham values in the vitamin E-treated kidneys. The cytoprotective heat shock protein (HSP70) and the i ntracellular antioxidant superoxide dismutase (MnSOD, Cu/ZnSOD) were simila r in sham, remnant, and vitamin E-treated remnant kidneys. We conclude that the sudden reduction of renal mass secondary to the 5/6 nephrectomy proced ure stimulates PLA, activity but not HSP70, MnSOD, or Cu/ZnSOD. This increa sed activity of PLA, in the remnant kidney returned to sham values after vi tamin E treatment. The intrinsic cellular antioxidant enzymes, MnSOD, Cu/Zn SOD, as well as the cytoprotective heat shock protein HSP70. showed no sign ificant changes in either vitamin E-treated or untreated kidneys compared w ith sham, These data are suggestive that the elevation of PLA, is a specifi c and localized response to the sudden reduction of renal mass.