Abstract

The effect of oxidative stress induced by different concentrations of hydrogen peroxide on dog neutrophils was studied. This effect was measured using dichlorofluorescein-diacetate (DCFH-DA) and by the cell surface membrane expression of heat shock protein (HSP) 27 kDa, HSP 72 kDa and HSP 90 kDa families. Hydrogen peroxide induced a concentration-dependent increase in DCFH oxidation (from 10(-6) M to 10(-4) M), and an increase in the cell surface expression of HSPs families. At a concentration of 10-4 hi, the percentage of positive cells that showed an oxidation of DCFH was 94.7% +/- 5.2 (n = 3). Only vitamin E (but not vitamin C) at a concentration of 0.5 mM was able to inhibit the intracellular oxidative stress induced by hydrogen peroxide. The percentage of positive cells that express these proteins after the treatment with hydrogen peroxide (10-4 M) was: 74% +/- 3.5 for HSP 27, 72% +/- 2.6 for HSP 72 and 73% +/- 1.2 for HSP 90 (n = 3). This cell surface expression was not abolished by either vitamin C or vitamin E. Localization of HSPs in plasma membrane is of immunological interest because they have been implicated in autoimmune diseases. (C) 1999 Elsevier Science Ltd. All rights reserved.