title: Prophylactic corticosteroid suppresses endotoxemia in heat-stressed primates.
abstract: We previously found that lipopolysaccharides (LPS) leak from the gut lumen into the hepatic portal vein during heat stroke. Furthermore, we found that prophylactic corticosteroid administration could prevent a rise in plasma LPS concentration in superior mesenteric artery occlusion shock. In this study, we found that treatment prior to heat-stress with corticosteroids could prevent any rise in plasma LPS concentration in heat-stressed primates. Two groups of primates, one of which received a prophylactic dose of methylprednisolone sodium succinate (MPSS) (n = 4) were subjected to heat-stress (41 +/- 0.3 degrees C). Their arterial blood pressure, heart rate and rectal temperature (Tr) were continuously recorded. In the untreated control group (n = 8), the plasma LPS concentration tended to increase slowly at a Tr of 41.5 degrees C from an initial 0.06 +/- 0.013 ng.ml-1. Above a Tr of 43 degrees C, the plasma LPS level rose rapidly until at a Tr of 44.4 +/- 0.1 degrees C, the mean LPS level was 0.315 +/- 0.03 ng.ml-1 (p less than 0.001). Prophylactic treatment with MPSS suppressed the increase in plasma LPS levels to 0.066 +/- 0.01 ng.ml-1 before heat-stress and 0.03 +/- 0.01 ng.ml-1 at Tr 44.4 degrees C just before primate demise. The mean arterial pressure of the control group was lower than the treated group for any given Tr; between Tr 42-43 degrees this difference was significant (p less than 0.05). Moreover, the cardiovascular parameters began to deteriorate at a lower Tr in the control group.
authors.affiliation: Department of Physiology, University of Durban-Westville, South Africa.
authors.forename: P
authors.initials: P
authors.lastname: Gathiram
authors.forename: S L
authors.initials: SL
authors.lastname: Gaffin
authors.forename: J G
authors.initials: JG
authors.lastname: Brock-Utne
authors.forename: M T
authors.initials: MT
authors.lastname: Wells
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001831:Body Temperature; D002522:Chlorocebus aethiops; D004731:Endotoxins / Q000097:blood*; D005260:Female; D006339:Heart Rate; D006359:Heat Exhaustion / Q000097:blood / Q000517:prevention & control*; D008070:Lipopolysaccharides / Q000097:blood; D008297:Male; D008775:Methylprednisolone / Q000031:analogs & derivatives*; D008776:Methylprednisolone Hemisuccinate / Q000627:therapeutic use*
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D008776:Methylprednisolone Hemisuccinate; D008775:Methylprednisolone