The use of slaughterhouse-obtained small intestinal tissue as control material in histological studies should be applied with prudence
K. De Ceulaer1, C. Van Ginneken1,2, C. Delesalle2,3, L. Van Brantegem1,2, P. Deprez2 and A. Weyns1
1Laboratory of Veterinary Anatomy, Embryology and Pathology, Department of Veterinary Sciences, University of Antwerp, Antwerp, Belgium, 2Department of Large Animal Internal Medicine and Clinical Biology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium and 3Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
Offprint requests to: C. Van Ginneken, Universiteitsplein 1, 2610 Antwerp, Belgium. e-mail: email@example.com
Summary. This study aimed to evaluate the reliability of slaughterhouse-obtained small intestinal tissue as control material in equine colic research where molecular stress responses in small intestinal tissue are investigated. For this purpose, small intestinal samples from colic horses were collected during surgery or immediately after euthanasia at the oral border of strangulation resection sites and routinely processed for histopathology (i.c. rinsed with 4°C Krebs’ solution, fixated overnight with 4% neutral buffered formaldehyde (FH) at room temperature). Control samples consisted of pieces of mid-jejunum, collected at the slaughterhouse and routinely processed for histopathology under 4 different conditions. The 4 conditions differed with regard to incubation and fixation temperature and whether or not oxygenated Krebs’ solution was used. Histological scoring revealed that slaughterhouse samples had a higher mean lesion score (P<0.001) than colic samples. In addition, more slaughterhouse samples had a higher mean inflammation score than colic samples (P=0.001). The inflammatory cells in the small intestine consisted mostly of eosinophils and as such were very suggestive for parasitic infestation. Hypoxia-inducible factor-1α (HIF1α) nuclear immunoreactivity was more pronounced in slaughterhouse tissue, probably as a result of the delay between slaughter and sampling (P=0.034). The histopathological score (P=0.291), the inflammation score (P=0.248) and the HIF1α nuclear immunoreactivity (P=0.538) did not differ between the different collection protocols. It is concluded that slaughterhouse-obtained small intestinal tissue shows distinct alterations and that its use as control tissue when evaluating molecular stress responses should be applied with prudence. Histol Histopathol 26, 427-431 (2011)
Key words: Horse intestine, Slaughterhouse, HIF1α, Histology