PSX-A-25 Late-Breaking: The Effects of Chronic Endotoxinemia on Rectal and Subcutaneous Temperature in Wethers

Abstract

Abstract Lipopolysaccharide (LPS) is responsible for inflammation and fever resulting from infections associated with gram-negative bacteria. Twenty-two wethers underwent a chronic LPS challenge in which they were assigned to one of five groups – control (CON; saline IV daily; n=4), single acute dose (SAD; 400 ng/kg bw on D1 and saline D2-7 IV; n=4), daily acute dose (DAD; 400 ng/kg bw IV; n=5), daily increasing dose (DID; 400 ng/kg bw with 20% increase each day IV; n=5), and subcutaneous steady dose (SSD; 20 ug /kg bw per day SQ; n=4). Wethers were equipped with subcutaneous temperature (SCT) sensors (data analyzed hourly; -1 to 148 h) and rectal temperatures (RT) were determined multiple times a day for six days (-1 to 147 h). Two-way ANOVA was completed using SAS v9.4 (Cary, NC) on both the SCT and RT data. There was an effect of treatment, time and an interaction of time and treatment (all P < 0.0001) on RT. Rectal temperature was greater than CON (38.9°C) in SAD (40.5°C), DAD (40.5°C), and DID (40.9°C) groups 3 h after treatment on D1, and the SSD (40.5°C) by 5 h after treatment on D1. While the greatest RT was at 5 h after treatment on D1 for SAD (41.1°C), DAD (41.3°C) and DID (41.8°C) groups. Compared to CON (~38.6°C), RT was increased 3 h after treatment administration on D2 (40.1°C), D3 (39.9°C), D5 (40.1°C), and D6 (39.9°C) for DAD and on D2 (40.1°C) and D5 (39.9°C) for DID. For SCT, there were effects of treatment and time (P < 0.0001), but no interaction (P = 1.00). The SSD group had the greatest SCT (38.3°C) followed by DID (37.7°C), DAD (37.5°C), SAD (37.3°C) and CON (36.9°C). Overall, chronic endotoxin did induce an increase in RT and SCT, but differently with RT changing over time.