Vol 67, No 1 (2008)
Original article
Published online: 2007-12-03
Immunoexpression of constitutive and inducible cyclo-oxygenase isoforms in the rat foetal and maternal digestive tract
Folia Morphol 2008;67(1):24-31.
Abstract
Cyclo-oxygenase (COX), which catalyses the conversion of arachidonic acid
to prostaglandin endoperoxide and prostanoids, is widely expressed in mammalian
organs. The aim of the study was to evaluate the immunoexpression
of the constitutive and inducible cyclo-oxygenase isoforms (COX-1 and COX-2
respectively) in the oesophagus, stomach and the small and large bowels of
untreated rat dams and foetuses on gestational day 21. The localisation of
the COX isoforms was similar in the maternal and foetal organs, although
the intensity of the reaction for COX-2 was stronger in the foetuses. Cytoplasmic
COX-1 immunostaining was found in myocytes of the muscularis
propria, muscularis mucosae and the blood vessels. It was also positive in
the endothelial cells, scattered stromal cells of the lamina propria and the
ganglion cells of the nerve plexus in the bowels. Apart from the keratinised
layer, a strong reaction was revealed in the stratified squamous epithelium
of the oesophagus and forestomach. Negative or weakly positive staining
was found in the mucus-secreting cells covering the surface, gastric pits
and pyloric glands, as well as in the parietal cells and the chief cells. Weakly
positive COX-1 immunostaining was observed in epithelial cells of the small
intestine crypts, but in some cases enterocytes and goblet cells covering
villi were also positive. In the colonic mucosa weak COX-1 staining was
typical of the absorptive, and goblet cells. The COX-2 immunostaining was
nuclear and/or cytoplasmic. An inconsistent positive reaction was seen in
the muscle of the muscularis mucosae, muscularis propria and the blood
vessels. Positive staining was also found in scattered stromal cells of the
lamina propria and adventitia and the ganglion cells. Weak nuclear staining
was found in the stratified squamous epithelium of the oesophagus and
forestomach. Unlike the strong foetal reactivity in the epithelial cells of the
glandular stomach, a negative or weakly positive reaction was seen in the
maternal parietal and/or mucous-secreting surface stomach cells. Some epithelial
cells of the crypts both in the small and large bowel were also COX-2
positive. In conclusion, constitutive and inducible COX isoforms were detected in the digestive tract of pregnant female and in foetuses. COX-1
was the predominant isoform in both the adult and foetal organs.
(Folia Morphol 2008; 67: 24-31).
(Folia Morphol 2008; 67: 24-31).
Keywords: cyclo-oxygenaseCOX-inhibitorlactationNSAIDpregnancyprostaglandin-endoperoxide synthaseoesophagusstomachsmall bowellarge bowel