Identifying diagnostic endocrine markers and changes in endometrial gene expressions during pyometra in cats

• Plasma concentrations of LTB4 and LTC4 are not useful diagnostic markers of pyometra, in contrast to 6-keto-PGF1α.
• Treatment with MPA did not evoke either endocrine or molecular changes in endometria of cats.
• The highest expression of TLR2/4 is observed only during severe endometrial disturbance like pyometra.

Pyometra is a significant reproductive problem in cats. The aims of this study were to evaluate (i) the immunological profile of queens by studying plasma concentrations of metabolites of prostacyclin I2 (6-keto-PGF1α), leukotriene B4 (LTB4) and leukotriene C4 (LTC4); and (ii) the gene transcription profiles of Toll-like receptors (TLRs) 2 and 4 (TLR2/4), PGE2-synthase (PGES), PGF2α-synthase (PGFS) and prostaglandin-endoperoxide synthase 2 (PTGS2) in the feline endometrium throughout the estrous cycle, after medroxyprogesterone acetate (MPA) treatment and during pyometra.The concentration of plasma 6-keto-PGF1α in pyometra was increased in comparison to other groups studied (p < 0.01). Endometrial mRNA coding for TLR2 was up-regulated in cats suffering from pyometra compared to other groups (p < 0.001). Expression of mRNA for TLR4 was up-regulated in endometria originating from MPA-treated cats, pyometra and late diestrus cats, compared with tissues from cats during estrus and anestrus (p < 0.05). As expected, endometrial mRNA for PTGS2 was up-regulated only in pyometra, compared with other groups (p < 0.001). Similarly, endometrial mRNA for PGFS was up-regulated in pyometra, compared with endometria from anestrus, late diestrus and from MPA-treated cats (p < 0.05), or from cats during estrus (p < 0.01).Overall, these results indicate that plasma concentrations of LTB4 and LTC4 are not useful diagnostic markers since they were not increased in queens with pyometra, in contrast to 6-keto-PGF1α. In addition, treatment with MPA evoked neither endocrine nor molecular changes in endometria of cats.