Estrogen and progesterone receptor status of mammary carcinomas and correlation with clinical outcome in dogs.

Estrogen and progesterone receptors (ER, PR) were measured in cytosol fractions from 18 primary canine mammary carcinomas by use of biochemical assays. One or both receptors were detected (> 10 fmol/mg of cytosol protein) in 11 tumors: 5 ER and PR; 2 ER only; 4 PR only. Mean cytoplasmic receptor concentrations (fmol/mg of cytosol protein) were 22.8 +/- 2.9 (SEM) for ER and 51.0 +/- 10.3 for PR in tumors containing ER and PR, 28.8 +/- 12.1 for ER in tumors containing only ER and 13.2 +/- 1.5 for PR in tumors containing only PR. Estrogen or progesterone receptors or both were identified in 6 of 9 tubular adenocarcinomas, 4 of 5 papillary adenocarcinomas, and 1 of 1 squamous cell carcinoma. These receptors were not identified in solid carcinomas (n = 2) or a single spindle cell carcinoma. Although the number of cases was limited, survival times of dogs tended to be longest in those with tumors containing ER alone or in combination with PR, intermediate in those with tumors containing only PR, and shortest in those with tumors without ER or PR. A correlation was not apparent between receptor status and age, presence of ovaries, tumor size, or histologic classification of the tumor. In the analysis of this series, the extent of surgery (mastectomy of the involved gland vs unilateral or bilateral mastectomy) did not appear to influence the outcome of the disease, and metastasis to regional lymph nodes did not appear to be a reliable prognostic indicator.     

Immunohistochemical features of canine ovarian papillary adenocarcinoma and utility of cell block technique for detecting neoplastic cells in body cavity effusions

Dogs with ovarian papillary adenocarcinoma occasionally present with ascites and/or pleural effusion. These aspirated fluids often contain a large number of cells, and distinction between neoplastic cells and activated mesothelial cells can be difficult. In this study, 7 cases of canine ovarian papillary adenocarcinoma, including 3 with ascites and pleural effusion, were immunohistochemically examined. Ovarian tumor cells were positive for cytokeratin CAM5.2 (CAM5.2), Wilms’ tumor 1 (WT-1) and progesterone receptor (PR) in all 7 cases. A metastatic lesion of the mediastinum in one case was also positive for CAM5.2, WT-1 and PR. Immunohistochemistry on cell blocks obtained from ascites and/or pleural effusion of 2 cases revealed the presence of PR-positive epithelial cells. Whereas, activated mesothelial cells in ascites or pleural effusion collected from dogs without neoplastic lesions were negative for PR. In addition, surface epithelium and subsurface epithelial structures (SES) of normal canine ovaries, that are considered to be the cell of origin for ovarian papillary adenocarcinoma, were also positive for CAM5.2, WT-1 and PR. These results indicate that, together with CAM5.2, WT-1 and PR is a useful diagnostic marker for canine ovarian papillary adenocarcinoma. Expression of PR may be associated with progesterone-dependent nature of canine ovarian papillary adenocarcinoma.     

Cellular proliferative and telomerase activity in canine mammary gland tumors

In canine mammary tumors, we examined the telomerase activity, proliferative activity by proliferative cell nuclear antigen (PCNA) immunohistochemistry, and percentage of apoptotic cells by the deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. The relationship between these measures and histopathologic malignancy was also investigated. PCNA index was highest in malignant tumors (adenocarcinoma: 27.0%; malignant mixed tumor: 15.7%), followed by benign tumors (adenoma: 4.4%; benign mixed tumor: 5.3%), hyperplasia (2.1%), and normal mammary gland (0.9%). In adenoma and adenocarcinoma, papillary and solid types showing higher cellularity tended to have higher PCNA indices than did cystic and tubular types. Although the TUNEL index was <1% in all cases, the relationship between this measure and histopathologic diagnosis showed the same tendency as observed in PCNA immunostaining. Telomerase activity was detectable in all adenomas, benign mixed tumors, and adenocarcinomas examined. In contrast, all normal mammary glands, hyperplasias, and malignant mixed tumors were negative for telomerase. Relative telomerase activity (RTA) of adenocarcinoma (56.5) was significantly higher than that of adenoma (27.8) and benign mixed tumor (33.9), and a significant positive correlation (P < 0.001) was noted between RTA and PCNA index. No significant correlations were noted between either PCNA or TUNEL index and clinical features such as metastasis and tumor diameter. PCNA index and telomerase activity may be useful markers for judging malignancy of canine mammary tumors.     

Canine bile duct carcinoma

Twenty-four adenocarcinomas of the hepatobiliary system were found among 110 primary hepatic neoplasms: 22 of these were intrahepatic, one involved the extrahepatic bile duct and one the gall bladder. Histologically, 10 intrahepatic neoplasms were classified as cholangiocarcinoma, and 12 as bile duct cystadenocarcinoma. The former were characterized by tubular structures lined by anaplastic cuboidal or columnar cells with diffuse fibrous stroma, and the latter by multiple cystic structures with papillary and solid areas. Half the bile duct cystadenocarcinomas showed benign cysts and transition to adenocarcinomas. This was seen in only one case of cholangiocarcinoma. The extrahepatic bile duct carcinoma was characterized by tubular structures lined with flattened cuboidal cells with scant stroma. The gall bladder adenocarcinoma contained many acinar structures lined with columnar or cuboidal cells and separated by thin stroma. Distant metastasis was found in 87.5% (21 of 24) sites of metastasis.     

Enzootic nasal adenocarcinoma of sheep in Slovenia

SUMMARY Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 +/- 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin-embedded tissues revealed the presence of the virus-like particles with an average diameter between 70 and 90 nm.     

Clinical and histopathological features and prognosis of gastrointestinal adenocarcinomas in Jack Russell Terriers

There has been an increase in the number of Jack Russell Terriers (JRTs) diagnosed with adenomas and adenocarcinomas of the gastrointestinal tract in Japan. This study retrospectively investigated the clinical and histopathological features and prognosis of adenocarcinomas arising in the gastrointestinal tract in JRT dogs. Seven JRTs and 39 dogs of other breeds diagnosed with gastrointestinal adenocarcinoma were included in the study. The most common sites of gastrointestinal adenocarcinoma in JRTs were the pylorus and rectum. On histopathological examination, these adenocarcinomas showed a papillary or tubular growth pattern, and the lesions were confined within the mucosal epithelium and poorly invasive. Among all dogs with gastric adenocarcinoma, the median survival time (MST) for five of the JRTs could not be determined because more than half of the cases remained alive, while the MST for nine non-JRT dogs was 34 days. Among all dogs with adenocarcinoma in the large intestine, the MST for three of the JRTs could not be determined, while the MST for nine non-JRT dogs was 1,973 days. The difference in MST between JRT and non-JRT dogs with gastric adenocarcinoma was significant (P=0.0220). Since gastrointestinal adenocarcinomas in JRTs show distinct characteristics with respect to their clinical features, treatment course, and prognosis, a different surgical and medical treatment plan should be considered compared to the management of gastrointestinal adenocarcinomas in other dog breeds.     

Histogenesis of the ovine uterus

Reproductive tracts from fetal (d 55 to 150) and neonatal (d 9 to 3 mo) lambs were examined by light microscopy in order to describe ovine uterine histogenesis. Morphologically, d-55 and -60 fetal uteri were bipartite, though characteristic external cornual morphology was not apparent until d 100 to 110. Histologically, lumina of d-55 and -60 fetal uteri were tubular and smooth with no indication of caruncular or glandular areas. In d-90 to -100 fetal uteri, luminal clefts were visible along the mucosal surface and a band of eosinophilic, elongated, smooth muscle-like cells was distinguishable. By d 100 to 110, nodular and internodular areas were clearly defined as luminal clefts deepened. Expansion of deep internodular areas, parallel to the luminal nodular surface, progressed in fetal uteri from d 118 to 150. Slight invaginations along deep internodular areas were visible in d-135 fetal uteri and were regular features of d-150 fetal uteri. In contrast, shallow, slightly coiled simple tubular glands were visible in the endometrium of internodular (intercaruncular) areas in a d-9 neonatal uterus. Older neonatal uteri (d 26 to 3 mo) contained coiled tubular glands which extended to the myometrium. Data indicate a systematic pattern of ovine uterine histogenesis involving dynamic morphogenetic alterations, especially between d 80 to 130 of fetal life. The observation that uterine glands were absent in fetal uteri but present in neonatal uteri suggests that glandular induction must occur during the periparturiet/neonatal period.     

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.     

Prospective survey of neoplastic and non-neoplastic uterine disorders in 116 domestic rabbits (Oryctolagus cuniculus)

BackgroundEarlier studies indicate that the risk for uterine tumours in rabbits may be as high as 60–80%. This high occurrence and the need for routine neutering of non-breeding pet rabbits have recently been in the spotlight.MethodsThis study aimed to describe and compare macroscopic and histopathological alterations in uteri collected from domestic rabbits of various ages that were neutered, deceased, or euthanized without a suspected uterine disorder (NoUD; n = 94) and from rabbits with a suspected uterine disorder (UD; n = 22).ResultsIn the NoUD group, uteri of 41 rabbits (44%) displayed histopathological findings and 12 rabbits (13%) had neoplasms. Samples from thirteen rabbits (14%) evinced histopathological findings with no macroscopic alterations. The most frequent diagnoses were cystic endometrial hyperplasia (26% of the 41 uteri), adenocarcinoma (9%), and polyps (5%). In the UD group, uteri from 21 (95%) out of 22 rabbits exhibited pathological alterations; in 2 (10%) of these, the changes (cystic endometrial hyperplasias) were seen only in histology. The most frequent diagnoses in the uteri of the UD group were cystic endometrial hyperplasia (77%) and adenocarcinoma (54%). Uterine malignant neoplasia affected 40% of all rabbits aged over 3 years, and the odds of a malignant uterine tumour in these rabbits were approximately 19-fold higher than in rabbits aged under 3 years.Conclusions and clinical relevanceUterine disorders are common in domestic rabbits, even without a suspected uterine disease, and the risk of uterine neoplasia markedly increases after 3 years of age. A macroscopically normal uterus may have pathological changes and ovariohysterectomy should be therefore preferred over ovariectomy at least in older rabbits.     

Immunohistochemical Expression of Cyclooxygenase‐2 (COX‐2) in Feline Endometrial Adenocarcinoma and in Normal and Hyperplastic Endometria

Cyclooxygenase‐2 (COX‐2) is overexpressed in several human and animal neoplasms, including the human endometrial carcinoma. It has been suggested as a prognostic marker and a potential therapeutic target. This study aimed to (i) clarify histological aspects of feline endometrial adenocarcinomas (FEA) of the papillary serous type and (ii) characterize COX‐2 immunohistochemical expression in normal, hyperplastic and neoplastic endometrium in this species. Archived paraffin‐embedded tissue samples of 33 FEA, eight cystic endometrial hyperplasias (CEHs) and 21 samples of normal, healthy endometrium in the follicular (FS; n = 10) and luteal (LS; n = 11) stages were evaluated. Histological evaluation of haematoxylin and eosin‐stained sections of the FEA revealed a papillary proliferation of neoplastic cells of serous type, accompanied by clear and multinucleated cells. Other architectural arrangements mainly included solid and tubular growth. Randomly distributed areas of necrosis within the tumours were commonly observed. Invasion of the myometrium, of the serosa and of the vascular and/or lymphatic vessels was not constant features. The mean number of mitoses was higher in FEA compared to non‐neoplastic endometrium. COX‐2 scores were lower in FEA (p = 0.003) and CEH (p = 0.05) when compared to normal epithelium (NE). The loss of the membrane apical reinforcement in epithelial cells was observed in FEA samples, which was accompanied by the dislocation of COX‐2 labelling into the cytoplasm and the perinuclear area; in contrast, in epithelial cells in the healthy and hyperplastic endometria, the immunoreaction showed the characteristic pattern of apical membrane reinforcement, suggestive of the membrane polarization. COX‐2 epithelial scores were higher in the FS than in the LS. No differences were found in stromal COX‐2 expression between normal, CEH and FEA groups, but it was higher in the LS than in the FS. In summary, loss of COX‐2 compartmentalization in neoplastic epithelial cells might be one of the molecular events underlying endometrial carcinogenesis.     

Iridociliary epithelial tumors in 100 dogs and 17 cats: a morphological study

The morphological features of iridociliary epithelial tumors in 100 dogs and 17 cats were reviewed. Twenty-seven cases were in either Golden Retrievers or Labrador Retrievers. Affected globes were stained for light microscopy with alcian blue, periodic acid Schiff (PAS) and hematoxylin and eosin stains. Selected tissues were examined by immunohistochemistry for vimentin, desmin, cytokeratin, S-100, neuron-specific enolase (NSE), and glial fibrillary acid protein (GFAP). The presence or absence of hyaluronic acid was recorded by staining with alcian blue before and after digestion of the tissue with hyaluronidase. Canine tumors were divided into papillary and solid tumors based on the pattern of growth. Twenty-eight of 57 papillary tumors exhibited invasive behavior including eight of the 57 which showed infiltration of the sclera. Twenty-nine of 43 solid tumors were invasive including 13 of 43 with scleral invasion. Tumors with scleral invasion were designated adenocarcinoma. Tumors of both types could be pigmented or nonpigmented and often contained smooth basement membranes reminiscent of the inner membrane of the nonpigmented ciliary body epithelial cell. All of the feline tumors were nonpigmented and 14 of 16 feline tumors were solid and two of the tumors were papillary. Eighteen of 20 canine tumors and three of four feline tumors stained positive for vimentin. Cytokeratin stain was positive only in a few of the highly aggressive tumors. The finding of pigmented epithelial cells, thick, smooth basement membrane structures, positive staining for vimentin, S-100, and NSE as well as hyaluronic acid deposition were considered to be features which define iridociliary epithelial tumors in dogs. The positive staining for vimentin and NSE are highly specific markers which help to characterize iridociliary epithelium and distinguish this tumor from metastatic epithelial tumors. The finding of solid nonpigmented tumors with small epithelial cells packeted by thin PAS-positive membranes staining positive for vimentin were considered significant features defining iridociliary epithelial tumors in cats. Follow-up information on survival and cause of death was obtained on 43 canine cases and only two feline cases. The average follow-up interval in dogs was 25 months and only two dogs died with lesions that could have been due to metastasis although neither was confirmed. We concluded that neither iridociliary adenomas nor adenocarcinomas is likely to metastasize.     

Cytological features of canine ovarian tumours: a retrospective study of 19 cases

The cytological features of 19 histologically confirmed canine ovarian tumours were retrospectively examined. Seven cases were cytologically classified as papillary adenocarcinoma, eight cases as granulosa cell tumours, two cases as mature ovarian teratomas, one case as a dysgerminoma and one case as a mixed granulosa cell tumour/dysgerminoma. On cytology, papillary adenocarcinoma was characterised by a papillary glandular pattern and tight cohesiveness. Granulosa cell tumours showed monolayered clusters of loosely cohesive granulosa cells. Call-Exner-like bodies were found in five of seven cases. Granulosa cells appeared to be heterogeneous and usually contained several intracytoplasmic vacuoles. Teratoma was characterised cytologically by keratin debris (two cases) and a mixture of epithelial cells with sebaceous, basaloid, columnar/palisading or ciliated appearance (one case). The dysgerminoma contained severely atypical round cells admixed with small lymphocytes. The mixed dysgerminoma/granulosa cell tumour had a mixture of germinal and granulosa cells. Cytological diagnosis was in agreement with histopathology in 18 of 19 (94.7 per cent) cases.     

Origin of enzootic intranasal tumor in the goat (Capra hircus): a glycohistochemical approach

Enzootic intranasal tumor (EIT) appears glandular in type and has recently been classified as an adenocarcinoma of low malignancy. The aim of this study was to characterize the secretion of surface glycoconjugates (GCs) in EIT and in normal respiratory and olfactory mucosae of the goat by means of conventional and lectin histochemistry, in order to shed light on the histogenesis of EIT. Morphologic and ultrastructural investigations showed two growth types of EIT: i.e., tubular and papillary patterns. Conventional histochemistry revealed the presence of neutral and carboxylated GCs in the olfactory glands and in the tubular part of EIT, as well neutral and sulphated GCs in the respiratory glands and in the papillary part of EIT, suggesting that the papillary pattern tumor arises from the respiratory glands, whereas the tubular portion of EIT arises from the olfactory glands. Lectin histochemistry gave further information on the expressed GCs.     

Relationship between receptors for insulin-like growth factor- I, steroid hormones and apoptosis-associated proteins in canine mammary tumors

In the veterinary literature there are few data concerning the expression of insulin-like growth factor type I (IGF-IR) in the canine mammary gland tumors. The aim of the present study was the evaluation of IGF-IR expression and its correlation to the expression of estrogen receptor alpha (ERalpha) and progesterone receptor (PR), proteins: Bcl-2, Bax, p53 in canine mammary gland tumors, and also a correlation with other features: bitch's age, tumor diameter, histologic type of tumor, degree of histologic malignancy, proliferate activity. The study was done on 112 epithelial neoplasms: 21 (19%) were adenoma, 38 (34%) complex carcinoma (adenocarcinoma), 47 (42%) simple carcinoma (adenocarcinoma) and 6 (5%) solid carcinoma. Histochemistry and immunohistochemistry methods were employed. It was shown that more common and/or higher IGF-IR expression in cells of canine mammary gland tumors was related to the histologic type of cancer of worse prognostic (solid and simple carcinoma), high histologic degree of malignancy (III degrees) but the statistical analysis did not reveal any significant differences. We observed the high degree of IGF-IR expression in tumors which displayed the high ERalpha and PR expression. These results suggest the involvement of IGF-IR in the development of hormonosensitive canine mammary tumors. Additionally, the significant positive correlation between expression of IGF-IR and p53, Bax was found. Our study provides some evidence that interactions exist between the IGF-IR and these apoptosis-associated proteins may contribute to the development and progression of canine mammary gland tumors. These results require further investigations.     

Naturally occurring nasal obstructions in 11 sheep

Eleven adult sheep of various breeds were examined due to inspiratory dyspnea. Fiberoptic examinations conducted in 8 of the sheep revealed masses to be obstructing the nasal passages. Identification of the masses through histopathologic examination showed 7 to be adenocarcinomas, 1 a papillary adenoma, and 4 were cases of glandular hyperplasia with lymphoplasmacytic infiltration (nasal polyps). One ewe had both an adenocarcinoma and a polyp. Surgical removal of the masses was attempted on 6 of the sheep. Four of the 6 surgically-treated sheep have survived between 2 mo. - 2 years without recurrence of the obstruction.     

Anal sac tumours of the dog and their response to cytoreductive surgery and chemotherapy

A retrospective study of anal sac tumours without pulmonary metastases, from the author's clinical records for the period July 1989 to July 2002, was conducted to establish the response to treatment with surgery and melphalan chemotherapy. Of 21 dogs with tumours of the anal sacs 19 had apocrine gland adenocarcinomas of anal sac origin, one had a benign papillary cystadenoma and another had a malignant melanoma. Two of the 19 dogs had bilateral anal sac adenocarcinomas. Ten of the 19 dogs with apocrine gland adenocarcinomas of anal sac origin had sublumbar lymphadenopathy. Five dogs were excluded by their owners from recommended treatment. Fourteen dogs with apocrine gland adenocarcinomas of anal sac origin were treated by surgical cytoreduction and chemotherapy with melphalan. Seven of the 14 dogs had regional lymph node metastases. Cytoreduction was by local excision of the anal sac in all 14 dogs and concurrent removal of the sublumbar retroperitoneal lymph nodes in the seven dogs with regional lymph node metastases. The median survival time of dogs with sublumbar nodal metastasis was 20 months and for dogs with tumour localised to the anal sac the median survival time was 29.3 months. There was no difference in median survival of those dogs with sublumbar metastases compared to those without. This study suggests there is a role for melphalan in the treatment of dogs with anal sac adenocarcinoma when combined with cytoreductive surgery, with treatment survival times and the local recurrence rate of the primary tumour comparing favourably with previously published treatment regimes.     

Post-mortem Examination of Sows Genital Organs Culled for Reproductive Disturbances and Immunohistochemical Studies on ERα and PR A Receptors in the Anoestral Sows Uterus

The aim of present study was post-mortem examination of ovaries, uterus and plasma oestradiol-17beta (E2) and progesterone (P4) concentrations in the blood of sows with reproductive disturbances and the distribution of oestradiol receptor (ERalpha), as well as progesterone (PR-A) in the anoestrous sows uteri. Reproductive organs of 150 crossbred sows (Lithuanian White x Danish Landrace) culled for the reasons of reproductive disturbances, were collected in local abattoir over a period of 3 months (September-November). Organs were assessed to determine the stage of the oestrous cycle or anoestrus and their development. Blood samples were collected for E2 and P4 analysis from the jugular vein 1 h prior to slaughter. For this study uterine samples only from pathological anoestrous sows were subjected to immunohistochemical staining to assess the distribution of ERalpha and PR-A in surface epithelium, subepithelial connective tissue, glandular epithelium and myometrium. Macroscopic examination of the ovaries showed that 68.7% sows had active cycling ovaries, 26.6% sows were anoestrus, ovaries were small without CL, and 4.7% of sows had multiple follicular cysts. In anoestrous sows (n = 27) the number and intensity of the nuclear staining of ERalpha varied between different uterine tissue compartments. The highest number (>80%) and the strongest intensity (+++) of positively stained cells for ERalpha was seen in myometrium and glandular epithelium. In other uterine wall compartments the number and intensity of positively stained for ERalpha nuclei was lower (+/++). The PR-A was absent from all tissue compartments. The intensity of the nuclear staining for ERalpha varied not only between the different uterine compartments but also between the sows. The 11.1% of the sows presented ERalpha in surface epithelium, 74.1% of the sows in glandular epithelium and 63.0% of sows in the myometrium.     

Prostatic adenocarcinoma with and without metastasis to bone in dogs

The signalment, clinical signs, and histologic tumor pattern were compared retrospectively in 12 dogs having primary prostatic adenocarcinoma with (5 cases) and without metastasis (7 cases) to bone. Weight loss and lumbar pain were observed more frequently in dogs having prostatic adenocarcinoma with metastasis to bone. A distinctive histologic pattern was not associated with prostatic adenocarcinoma that had metastasized to bone. The alveolar papillary pattern was the predominant histologic type observed in both groups. Metastasis to extrapelvic bony sites included the scapulas, ribs, and digits. The results of this study indicate that skeletal metastasis was not uncommon in dogs having prostatic adenocarcinoma.     

Distribution patterns of mast cells in the uterus of pregnant Meishan pigs

The present study was performed to investigate the numerical distribution of mast cells (MCs) in the uteri of pregnant Meishan pigs to explore the functions of MCs in pig pregnancy. The uterine samples from pregnant (on days 15, 26 and 50 of gestation) pigs were obtained respectively and stained with toluidine blue. The results were as follows: MCs were constitutively located in the uterus of the Meishan pig, with the distribution varying with gestational stages. On days 15 and 26 of gestation, MCs were mainly distributed around the blood vessels and uterine glands within the endometrium. On day 50 of gestation, MCs were mostly distributed in the myometrium. These results indicated that uterine MCs possibly have versatile functions in pig pregnancy.