Evaluation of dimethyl sulfoxide effects on endotoxin induced delayed gastric emptying in horses

Endotoxaemia is one of the most severe and ubiquitous disease processes in horses; and delayed gastric emptying is one of the most clinically significant manifestations of endotoxaemia. Current information suggests that oxidative damage plays a key role in the systemic effects induced by endotoxin and this raises the possibility that antioxidants, such as dimethyl sulfoxide (DMSO), might have a protective effect. No study has yet evaluated the efficacy of DMSO in ameliorating delayed gastric emptying caused by endotoxaemia in horses. We hypothesized that DMSO would ameliorate delayed gastric emptying caused by intravenous lipopolysaccharide (LPS) administration. Horses were randomly assigned to one of 4 groups; of 6 horses each: Normosol (Abbott Laboratories, Abbott Park, Illinois, USA) + LPS (0.2µg/kg bwt, i.v.); DMSO (1g/kg bwt, i.v.) + Saline; High-dose DMSO (1g/kg bwt, i.v.) + LPS; Low-dose DMSO (20 mg/kg bwt, i.v.) + LPS. All horses in all groups received acetaminophen (20 mg/kg reconstituted in one liter of warm tap water) by nasogastric intubation. Data for acetaminophen concentrations in the blood as a measure of gastric emptying were examined for the effect of treatment using a repeated-measures mixed-model ANOVA. A value of P < 0.05 was considered significant. Delayed gastric emptying occurred in all horses receiving LPS, as indicated by the lower concentrations of acetaminophen in these groups along the study period. DMSO did not ameliorate the effect of LPS on gastric emptying. Low-dose DMSO actually exacerbated the LPS-induced delay in gastric emptying. In this study, DMSO did not have any protective effect against LPS-induced delayed gastric emptying in horses.