Tissue antioxidant capacity and bacterial translocation under total parenteral nutrition

Alterations in the antioxidative system have been observed during total par enteral nutrition (TPN). Light exposure or changes in the composition of TP N formulas may affect this system. Bacterial translocation (BT) is frequent under TPN and may be related to oxidative status. The aim of this study wa s to determine the adverse effects of standard and glutamine-enriched TPN, with or without. light exposure, on oxidative status (liver and kidney-redu ced glutathione, GSH) and its relationship to BT. Thirty-three adult Wistar rats underwent central-venous cannulation and were randomly assigned to on e of four groups receiving different TPN regimes for 10 days. The TPN group (n = 10) had standard TPN, the TPN(-) group (n = 8) standard TPN without l ight exposure, the GTPN group (n = 8) glutamine-enriched TPN, and the GTPN( -) group (n = 7) glutamine-enriched TPN without light exposure. A sham grou p (n = 16) receiving chow and water ad libitum and saline i.v. served as co ntrols. At the end of the experiment, GSH was determined in liver and kidne y tissue. Mesenteric lymph nodes and peripheral and portal blood samples we re cultured for BT. Compared to sham rats, TPN groups had statistically sig nificant lower,GSH levels, but there were no differences between standard o r glutamine-enriched groups or light-exposure groups. Sham animals had 12% BT. Significantly higher BT (P < 0.05) occurred in TPN rats: 70% in the TPN group 88% in the TPN(-) group, 86% in GTPN (-) animals: and only 50% in th e GTPN group (P = 0.06 vs TPN group). In conclusion, (1) TPN reduces antiox idant capacity; (2) glutamine supplementation or light protection does not improve tissue antioxidant capacity under TPN; (3) the absence of light exp osure does not improve TPN-related BT, and (4) glutamine supplementation te nds to reduce BT only in the presence of light.