Immunoreactivity of iNOS in porcine uterus after infusions of Escherichia coli endotoxin.

The aim of this study was to investigate the distribution of inducible isoform of nitric oxide synthase (iNOS) in the porcine uterus after infusions of Escherichia coli endotoxin (lipopolysaccharide, LPS). In the group I (treated; n=6), 1 mg of LPS was infused into both the left and right uterine horn starting from the 4th to the 10th day of the estrous cycle, twice a day. In the group II (control; n=6), saline was infused into the uterus. The uterine horns were collected on the 14th day of the estrous cycle. Cryostat sections from the paraformaldehyde fixed tissues were stained immunohistochemically to estimate the distribution of iNOS. The luminal and glandular epithelium was stained more intensely for iNOS in the LPS-treated gilts than in the control animals. After LPS infusions, iNOS staining in vascular endothelial cells was also more intense than that observed in the controls. The present study has revealed that infusions of LPS into the porcine uterus result in an increase in the intensity of iNOS staining in some structures of this organ and supports our earlier data that NO can mediate an inflammatory effect of LPS in the uterus.