Uterine oestrogen and progesterone receptor expression in experimental pyometra in the bitch

Effect of systemic inflammatory response syndrome (SIRS) on prostaglandin metabolite and oxidative stress in canine pyometra

Pyometra, either open or closed cervix, inevitably progresses to systemic inflammatory response syndrome (SIRS), if ovariohysterectomy is not done timely. The aim of the study was to investigate the effect of pyometra led SIRS on certain serum biochemical and prostaglandin metabolite, 13,14-dihydro-15-keto PGF2 alpha (PGFM) and oxidative stress indices in the canine. The pyometra positive bitches were categorized as SIRS+ (n=29) and SIRS- (n =16) based on temperature (<100.5 or >102.5°F), respiration rate (>20/min), heart rate (>102/min), and total leukocytes count (<6×103 or >16×103 per μL). The SIRS+ bitches showed hypoalbuminemia, hyperglobulinemia, elevated blood urea nitrogen and creatinine, decreased super oxide dismutase (SOD) activity with moderate increase in the lipid peroxidation. Further, the SIRS+ bitches had significantly higher serum PGFM concentration (6.83±0.7 vs. 4.12±0.4 ng/mL) than SIRS- and the level was influenced by cervical patency. It was concluded that elevated serum PGFM along with hyperglobunemia, blood urea nitrogen, creatinine would be useful in diagnosis and monitoring of pyometra led SIRS in bitch.

The endometrium histopathology and cell ultrastructure in bitches with pyometra induced using progesterone and Escherichia coli

BACKGROUND

We investigated uterine histopathological and ultrastructural changes in female dogs with pyometra induced by Escherichia coli (E. coli) inoculation using progesterone and/or estradiol.

METHODS

Dogs were ovariectomized and classified into six groups: Groups 1-6 corresponding to estradiol treatment followed by progesterone supplementation, progesterone supplementation only, estradiol supplementation only, simultaneous treatment using estradiol and progesterone, similar to Group 1 but with a double dose, and control group, respectively.

RESULTS

Pyometra was successfully induced in Groups 1, 2, 4, and 5, but not in Group 3. An uneven endometrial surface was observed, along with a purulent discharge, bleeding, inflammatory lesions, cystic endometrial hyperplasia (CEH) or cystic endometrial atrophy. Endometrial thickness percentage, uterine wall thickness, and the percentage of endometrial cyst area increased. Endometrial epithelial mushroom-like hyperplasia and the honeycomb-like structure exposed under the epithelium after flaky exfoliation were found, and the glandular epithelial villi became longer or shorter. Mitochondria expansion and increased lysosome were observed. Endoplasmic reticulum dilation and swelling and many inflammatory cells, especially plasma cell infiltration in the stroma, were found.

CONCLUSIONS

Endometrial histopathology and ultrastructural changes in affected dogs were accompanied by induction of pyometra, and they were affected by different hormonal patterns and E. coli.

Morphological Characteristics and Expression of Estrogen and Progesterone Receptors in the Canine Endometrium During the Estrus Cycle, Cystic Endometrial Hyperplasia and Pyometra

The estrus cycle of bitches is divided into four phases: proestrus, estrus, diestrus and anestrus, during which different morphological changes, and also cyclic changes of estrogen and progesterone receptors are present. Several pathological changes can be differentiated on the endometrium, but one of these is the most important - cystic endometrial hyperplasia, which frequently develops into pyometra. The aim of the present study was to describe morphological characteristics, and expression of estrogen and progesterone receptors on the endometrium of mixedbreed bitches during the different phases of the estrus cycle, cystic endometrial hyperplasia and pyometra. The uterus and ovaries of 36 mixed breed bitches in different phases of the estrus cycle and also with cystic endometrial hyperplasia (CEH) and chronic purulent endometritis - pyometra were examined macroscopically, histopathologically, and immunohistochemically for estrogen receptors (ΕR) and progesterone receptors (PR). During proestrus uterine cells showed a weak reaction for both estrogen and progesterone receptors, but during estrus a large number of uterine cells showed a strong reaction on estrogen receptors and moderate reaction on progesterone receptors. On the contrary, during diestrus the scores for the estrogen receptors decreased, while the progesterone receptors level increased - uterine cells expressed strong reaction for progesterone receptors, and moderate reaction for estrogen receptors. Uterine cells in cystic endometrial hyperplasia expressed a strong reaction for estrogen receptors, and moderate reaction for progesterone receptors, but on the other hand the uterine cells in the uterus with pyometra expressed a moderate to strong reaction for progesterone receptors, and a weak reaction for estrogen receptors. In further investigations it would be interesting to perform quantitative analysis for both estrogen and progesterone receptors during different phases of the estrus cycle and also in the uterus with cystic endometrial hyperplasia and pyometra.

Expression of oxytocin, progesterone, and estrogen receptors in the reproductive tract of bitches with pyometra

Canine pyometra is considered a serious and life-threatening condition. Due to the relationship among sex steroid hormones, oxytocin receptor (OTR) expression, and canine pyometra pathogenesis, this study aimed to investigate the expression of oxytocin, progesterone, and estrogen receptors in the reproductive tissues of canines with pyometra by real-time PCR and immunohistochemistry. A total of 27 pyometra bitches were classified into open- and closed-cervix pyometra groups based on the presence of vaginal discharge. Moreover, 15 normal bitches in the luteal phase served as a control group. The results showed that OTR gene expression in the ovary of pyometra bitches was higher than that of normal bitches, whereas the level of OTR gene expression in the cervix of pyometra bitches was less than that of normal bitches (P < 0.05). Conversely, a lower OTR H-score in ovarian follicles was observed in pyometra bitches compared with normal bitches, whereas a higher percentage of OTR-positive immunostaining in uteri and cervices were found in pyometra bitches compared with normal bitches (P < 0.05). Moreover, the H-scores of estrogen receptor alpha in uteri and cervices of pyometra bitches were less than that of normal bitches (P < 0.05). However, the localization of the OTR and sex steroid receptors between groups of pyometra bitches was not different. Our findings suggest that pyometra pathogenesis is associated with a change in expression of OTR and sex steroid receptors in the canine reproductive tract. However, cervical dilation in bitches with pyometra was not influenced by the expression of OTR and sex steroid receptors.

Imunoistoquímica de útero e cérvice de cadelas com diagnóstico de piometra

Analisou-se a piometra de 31 cadelas, de raças e idades variadas, sendo 25 cadelas com piometra de cérvice aberta e seis de cérvice fechada. Após ovariossalpingo-histerectomia, foram coletados fragmentos da cérvice e do útero para a avaliação imunoistoquímica. Foram analisados os receptores de estrógenos α e β, progesterona e colágenos I e III. Foram realizadas imunomarcações em diferentes regiões da cérvice, como o epitélio glandular, o epitélio luminal e o estroma glandular, assim como em diferentes regiões do útero, como o epitélio glandular e o estroma glandular. As imunomarcações de colágenos I e III foram realizadas nas regiões glandular e muscular da cérvice e do útero. Concentrações de receptores de progesterona foram maiores em cadelas com piometra fechada.

A model for cystic endometrial hyperplasia/pyometra complex in the bitch

The objective of this study was to develop a reliable model for the study of the cystic endometrial hyperplasia and pyometra complex (CEH/P) in the bitch. Greyhound bitches (n = 15) were ovariectomised and allocated into three groups (Group 1, n = 5; Group 2, n = 5; Group 3, n = 10, including 5 used from Group 1). Simulated proestrus, estrus and diestrus were induced by treatment with estradiol benzoate and megestrol acetate. The duration of cervical opening during estrus was determined by the intra-vaginal infusion of radio-opaque medium and subsequent radiography of the uterus (Group 1). One milliliter of a culture of Escherichia coli (with five uro-pathogenic virulence factors as identified by PCR: pap, sfa, hlyA, cnf1 and fim) was inoculated intra-vaginally daily throughout the simulated estrus (Group 2). One milliliter of the culture (n = 6) or sterile Luria-Bertani broth (n = 4) was introduced directly into the uterus on simulated diestrus Days 8 or 12 (Group 3). Necropsies were performed 12 and 7-14 days after the inoculation (Groups 2 and 3). The cervix remained open throughout the duration of simulated estrus (5-6 days) in four out of five bitches, and for a shorter duration (3 days of a 6-day estrus period) in one bitch (Group 1). CEH/P was induced by inoculation of bacteria into the uterus (10/10 bitches) but not into the vagina (0/5 bitches), (P = 0.003). A model for the study of CEH/P has been validated.

Steroid Receptor Expression and HER-2/neu (c-erbB-2) Oncoprotein in the Uterus of Cats with Cystic Endometrial Hyperplasia-Pyometra Complex

The presence of oestrogen-alpha receptor (ER), progesterone receptor (PR), and HER-2/neu (c-erbB-2) oncoprotein in the uterine walls of 10 healthy cats and 20 subjects with cystic endometrial hyperplasia-pyometra (CEH-P) were evaluated. Lesions were graded according to the severity of cystic dilation, hyperplasia and inflammation, and were classified as normal, mild uterine hyperplasia and severe uterine hyperplasia. The ER, PR and c-erbB-2 expression in the endometrium, glandular epithelium, stromal fibroblasts and myometrial smooth muscle cells was quantified by immunohistochemistry. The ER, PR and c-erbB-2 staining patterns differed between normal uteri and uteri with CEH-P. The ER expression was tended to be higher in the endometrial surface and glandular epithelium in the severe hyperplasia group (P > 0.05) and significantly lower in the mild hyperplasia cases compared with normal endometrium (P < 0.05), whereas the PR expression in both severe and mild hyperplasia cases tended to be higher in stromal cells and glandular epithelium than those in the normal uteri. C-erbB-2 immunoreactivity was observed only in the endometrial surface and glandular epithelium of the uterine wall and immunostaining was found to be highest in cases with severe hyperplasia. As a conclusion, we suggest that c-erbB-2 oncoprotein may play a role in the pathogenesis of the CEH together with the ER and PR in cats, and that ER does not have a role in the mechanism of pyometra, whereas PR plays a role in the pathogenesis of both CEH and pyometra.

Serum estradiol-17β, progesterone and respective uterine cytosol receptor concentrations in bitches with spontaneous pyometra

The role of serum estradiol-17 beta (E(2)) and progesterone (P(4)) in relation to uterine estrogen (ER) and progesterone receptors (PR) was investigated in canine cystic endometrial hyperplasia-pyometra (CEH-P). Blood and uterine samples were collected pre- and post-ovariohysterectomy, respectively, from 54 bitches presenting spontaneous CEH-P and 25 healthy control bitches. Competitive enzyme immunoassays (EIA) and enzyme ligand immunoassays (ELIA) were applied to estimate serum hormones and uterine cytosol active receptors, respectively. Animals were classified in the stages of first half of diestrus, second half of diestrus and early anestrus on the basis of reproductive history, clinical signs, uterine and ovarian macro- and microscopic inspection and serum P(4) concentration. Bitches with CEH-P, compared to their respective stage controls, exhibited (a) similar P(4) fluctuations, (b) higher E(2) concentrations, (c) lower PR concentrations during diestrus first and second half and (d) lower ER concentrations during diestrus first half and early anestrus. Negative correlation was detected between P(4) and ER within both CEH-P and control groups. It was concluded that P(4) was the main uterine receptor regulator for both PR and ER during diestrus and early anestrus in healthy and affected uteri. However, in CEH-P bitches, high P(4) levels in diestrus appeared to over-activate uterine PRs, leading to stronger PR self-down regulation and ER suppression. These findings indicate an increased sensitivity of CEH-P uterus to P(4) action. During early anestrus, a complementary role of endogenous E(2) was considered, since reduction of P(4) action appeared to permit uterine ER replenishment and activation by relatively high E(2) levels.