Free Radical Research, Vol. 35, pp. 907 916 Reprints available directly from the publisher Photocopying permitted by license only © 2001 OPA (Overseas Publishers Association) N.V. Published by license under the Harwood Academic Publishers imprint, part of Gordon and Breach Publishing a member of the Taylor & Francis Group. All fights reserved. Changes in the Ascorbic Acid Levels of Peritoneal Lymphocytes and Macrophages of Mice with Endotoxin- induced Oxidative Stress VICTOR M. VICTOR, NOELIA GUAYERBAS, MARTA PUERTO and MONICA DE LA FUENTE* Department of Animal Physiology, Faculty of Biology, Complutense University, Av. Complutenses/n, E-28040Madrid, Spain Accepted by Professor A. Azzi (Received 1 March 2001; In revised form 30 March 2001) Ascorbic acid (AA) is an important cytoplasmic antioxidant that mice synthesize in the liver, the intracellular levels of which decrease in an oxidative stress situation such as endotoxic shock. The present work deals with the changes in AA levels, that modulate the immune ffmction, in the two main immune cells, namely macrophages and lymphocytes, from female BALB/c mice suffering endotoxic shock caused by intraperitoneal injection of Escherichia coli lipopolysaccharide (LPS) (100mg/kg). The intake by cells of this antioxidant present in vitro at different concentrations was also studied. The animals show an oxidative stress, standardized in previous studies, that causes mortality at 30 h after LPS injection. The cells were obtained from the peritoneum at 2, 4, 12 and 24h after LPS or PBS (control) injections and were incubated without or with AA at 0.01, 0.1 and I mM for 10, 30, 60, 120 or 180 min. The hepatic AA levels were also studied at 0, 2, 4, 12 and 24h after LPS injection. The peritoneal cells obtained from animals injected with LPS showed increased AA levels in relation to the control cells at all times after LPS injection, with maximal effect at 12h. The AA levels decreased after this time, in agreement with changes in the AA hepatic levels. The increase was due to the AA of lymphocytes since macrophages showed a decrease in AA at different times after LPS injection. Both cells showed an increase in the intracellular levels of AA when this antioxidant was added in vitro. This takes place mainly at 30-60min of incubation in cells from controls and at 10 min in cells from treated mice 12-24h after LPS injection. The incorporation decreased at these times of endotoxic shock, a few hours before death. In all cases AA levels were higher in lymphocytes than in macrophages, and l mM was the most effective concentration. These results suggest that the immtme cells need appropriate levels of antioxidants, such as AA, under oxidative stress conditions, and that while lymphocytes take and accumulate AA, macrophages use it. Keywords: Ascorbic acid; Macrophages; Lymphocytes; Oxidative stress *Corresponding author. Tel.: +34-91-394-4989. Fax: +34-91-394-4935. E-mail: mondelaf@bio.sim.ucm.es 907 Free Radic Res Downloaded from informahealthcare.com by Universitaetsbibliothek Duisburg-Essen on 05/20/14 For personal use only.