Impact of chronic catheterization and automated blood sampling (Accusampler) on serum corticosterone and fecal immunoreactive corticosterone metabolites and immunoglobulin A in male rats

Abstract

Jugular catheters were inserted in nine male rats under general isofluorane anesthesia and the catheters were connected to a commercially available computerized blood sampling device (Accusampler). Blood samples (150 µl) were collected every 4 h during the first 24 h after surgery and every 12 h during the following 72 h until 94 h after surgery, when the animals were killed. All fecal pellets were collected at blood sampling. Serum corticosterone and fecal concentrations of immunoreactive corticosterone metabolites and immunoglobulin A (IgA) were quantified by ELISAs. In blood, high corticosterone concentrations (.200 ng/ml) were recorded in the first samples obtained after surgery, but the concentrations decreased steadily during the day and became cyclical, showing a diurnal variation with high levels during evenings and low levels in the mornings. The automatic blood sampling itself did not result in recordable increases in serum corticosterone concentrations. The time delay between the presence of elevated corticosterone levels in blood and in feces was approximately 12 h. Fecal immunoreactive corticosterone metabolite levels remained elevated during the 94 h study period after surgery. The fecal concentrations of IgA showed substantial between-animal variation and decreased non-significantly after the surgery. Like serum corticosterone, fecal IgA showed a diurnal variation in amounts excreted, in this case with high values in the morning and low values in the evening. The concentrations of fecal corticosterone and IgA were negatively correlated in samples obtained before surgery but no correlation existed after surgery. This indicates that fecal immunoreactive corticosterone metabolites, but not IgA, constitute a good marker of acute stress. For immunoreactive corticosterone metabolites as well as for IgA, the concentration in feces correlated well with total excretion, making single fecal samplings usable as a measure of total secretion.

Seasonal variations in immunoreactive cortisol and fecal immunoglobulin levels in Sichuan golden monkey (Rhinopithecus roxellana)

“…Several environmental and physiological factors can affect the immune responses of animals under stress, and IgA has been suggested as a potential marker of long-term stress (Royo et al, 2004). In the present study, the stress responses of Sichuan golden monkeys living in seminatural conditions, but responding to the external environment and other factors, were within the normal physiological range.…”

Short-term voluntary exercise in the rat causes bone modeling without initiating a physiological stress response

“…By collecting feces over the first 4 h of the dark period, we obtained samples at the approximate fecal corticosterone nadir, which is the time most likely to reveal a stress response (5,45,60). Although plasma corticosterone levels may be more indicative of acute stress, measurement of fecal corticoids is well-suited to analysis of longer-term stressors (hours to days), since it quantifies a summated index of systemic corticoids proven to reflect stress responses (8,48). Reporting total fecal corticoids over time, instead of fecal corticoid concentrations, provides a more accurate representation of systemic corticoid production by taking into account the amount of feces produced during the sampling time period, which varies over the light-dark cycle (9).…”

The diet board: welfare impacts of a novel method of dietary restriction in laboratory rats

“…Faecal secretion of IgA is negatively correlated to faecal corticosterone secretion in rats. 69 In rodents, chronic stress (e.g. social stress, social isolation) is associated with decreased IgA secretion into the faeces 70 and into the saliva.…”