ARS | Publication request: THE EFFECTS OF ACUTE RESTRAINT STRESS ON LYMPHOCYTE PROLIFERATION AND IGM PRODUCTION AND CORTISOL LEVELS IN THE PIG

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: October 20, 2005
Publication Date: July 9, 2006
Citation: Burdick, N.C., Welsh, T.H., Carroll, J.A., Laurenz, J.C. 2006. The effects of acute restraint stress on lymphocyte proliferation and IgM production and cortisol levels in the pig [abstract]. Journal of Animal Science. 84:4(Suppl. 2). Abstract #12.

Technical Abstract: This study investigated the effect of acute restraint stress on lymphocyte IgM production and proliferation in vitro and plasma cortisol levels in vivo. Crossbred pigs (n=11; 35 days of age) were restrained and blood collected via jugular venipuncture initially (t = 1:34±0:09 min), and at 3 and 6 min. Plasma was collected and stored -80 C for cortisol analysis by EIA. Lymphocytes were isolated using density gradient centrifugation. Cultures were plated at 100,000 cells/well in media (DME/F12, 10% FBS, 2 mM L-glutamine, 50 U/m penicillin, 50 U/mL streptomycin, and 10 mM 2-mercaptoethanol) containing ConA (0 to 10µg/mL) and cultures incubated for 96 hours (37 C and 5% CO2). Following incubation, IgM content of culture supernatants was determined by ELISA and the extent of proliferation was determined using a CellTiter96™ (Promega, Madison, WI) proliferation assay. As expected, cortisol levels were affected by restraint time (P=0.05) with concentrations at 6 minutes being approximately 65% higher than initial and 3 min. In cultures, ConA induced dose-dependent increases (P<0.001) in lymphocyte proliferation and IgM production. Time of restraint affected (P<0.05) lymphocyte proliferation, with cultures established from pigs restrained for 3 min proliferating more (P<0.05) than those at initial and 6 min. IgM production was affected by time of restraint (P<0.001), with IgM production by cultures decreasing (P<0.05) with increasing restraint time. Regression analysis revealed a negative correlation (P<0.05) between in vivo cortisol levels and the sensitivity of isolated lymphocytes to ConA in vitro. Additional studies are warranted to further define the relationship between in vivo neuroendocrine treatments and in vitro assessment of immune function.