Are physiological effects of sleep deprivation in the rat mediated by bacterial invasion?

Recent reports have indicated that rats subjected to total sleep deprivation (TSD) by the disk-over-water method and sacrificed when death appeared imminent showed aerobic bacteria in their blood. Yoked control rats did not. Extrapolating from these results, it has been suggested that the late body temperature declines and eventual deaths of TSD rats are caused by septicemia, and that other, earlier-appearing effects of TSD-including weight loss, increased energy expenditure, and regulation of temperature at a higher level-might be mediated by impaired host defenses against bacterial invasion. Three measures of aerobic bacterial invasion were used to evaluate these hypotheses: bacteremia, bacterial colonization in major organs of filtration (liver, kidney, and mesenteric lymph nodes), and adherence of bacteria to the cecal wall. Experiment 1 showed nonsignificant trends toward more bacterial invasion in 4-day TSD rats compared to yoked control rats and no relationship between the bacterial indicators and the early TSD effects. Experiment 2 showed that the elimination of aerobic bacterial infection by antibiotic treatment did not prevent the early TSD effects in 4-day TSD rats. Experiment 3 showed that the elimination of aerobic bacterial invasion in TSD rats did not eliminate the late temperature decline or the progression towards death. The results showed no significant evidence of aerobic bacterial invasion early in TSD and no indication that the major effects of TSD were dependent upon aerobic bacterial invasion.