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Temporal effects of a severe‐heat load on intestinal integrity
Author(s) -
Pearce Sarah C.,
SanzFernandez Maria Victoria,
Baumgard Lance H.,
Gabler Nicholas K.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.944.3
Subject(s) - ileum , chemistry , zoology , dextran , ussing chamber , medicine , rectal temperature , endocrinology , biology , biochemistry , in vitro
Acute heat stress (HS) and heat‐stroke can be detrimental to health and well‐being of humans and animals. Objectives were to chronologically characterize a severe heat‐load's impact on intestinal integrity. Crossbred gilts (n=40; 65 ± 2.7 kg BW) were subjected to HS conditions (37°C; 40% humidity) with ad‐libitum intake for either 0, 2, 4, 6, or 12 h (n=8/time point). Rectal temperature (T r ) and respiration rates (RR) were determined every 2 h. Pigs were euthanized at each time point and fresh ileum and colon samples were mounted into modified Ussing chambers. Transepithelial electrical resistance (TER) and fluorescein isothiocyanate (FITC)‐labeled dextran permeability (APP) were assessed. Additionally, ileum heat shock protein (HSP) 70 protein expression was determined. As expected, T r increased linearly over time ( P < 0.01) with the highest body temperature difference observed at 12 h (2.6°C). Compared to the 0 h group, RR increased (230%; P < 0.01) in the first 2 h and remained elevated during the 12 h ( P <0.05). Ileal TER quadratically decreased ( P < 0.01), reaching its minimum at 4h (40% decrease relative to 0h). Dextran APP quadratically increased with time ( P < 0.05) peaking at 4h (1200%). Colon TER and dextran APP changed due to HS in quadratic responses over time ( P = 0.05) similar to the ileal measurements, but were less pronounced. The stress marker HSP 70 increased in a linear fashion over time due to HS ( P < 0.05). These data indicate that severe heat compromises intestinal integrity within 2 h and the maximum deleterious effects occur at 4 h.