Immunohistochemical evaluation of cell proliferation and apoptosis markers in ovaries and uterus of tamoxifen-treated rats

Establishment and comparison of different procedures for modeling intrauterine adhesion in rats: A preliminary study

The establishment of a stable animal model for intrauterine adhesion (IUA) can significantly enhance research on the pathogenesis and pathological changes of this disease, as well as on the development of innovative therapeutic approaches. In this study, three different modeling methods, including phenol mucilage combined mechanical scraping, ethanol combined mechanical scraping and ethanol modeling alone were designed. The morphological characteristics of the models were evaluated. The underlying mechanisms and fertility capacity of the ethanol modeling group were analyzed and compared to those of the sham surgery group. All three methods resulted in severe intrauterine adhesions, with ethanol being identified as a reliable modeling agent and was subsequently subjected to further evaluation. Immunohistochemistry and RT-PCR results indicated that the ethanol modeling group exhibited an increase in the degree of fibrosis and inflammation, as well as a significant reduction in endometrial thickness, gland number, vascularization, and endometrial receptivity, ultimately resulting in the loss of fertility capacity. The aforementioned findings indicate that the intrauterine perfusion of 95 % ethanol is efficacious in inducing the development of intrauterine adhesions in rats. Given its cost-effectiveness, efficacy, and stability in IUA formation, the use of 95 % ethanol intrauterine perfusion may serve as a novel platform for evaluating innovative anti-adhesion materials and bioengineered therapies.

The effect of melatonin on sheep endometrial epithelial cell apoptosis through the receptor and non-receptor pathways

Melatonin potentially regulates the female animal reproductive function, but its regulatory mechanism in the apoptosis of sheep endometrial epithelial cells (SEECs) remains to be elucidated. In the present study, immunofluorescence staining, western blotting, and quantitative real-time polymerase chain reaction were performed to detect the distribution of melatonin receptors (MT1 and MT2) in the uterus of sheep and the effect of melatonin via the receptor and non-receptor pathways on the apoptosis of SEECs in vitro. The results showed that melatonin inhibits the apoptosis of SEECs to varying degrees to regulate the expression of estrogen receptors (ERs) and progesterone receptors (PGR) via its interaction with MT1 and MT2. In addition, the ER antagonist partially relieved the inhibitory effect of melatonin on the apoptosis of SEECs, while the PGR antagonist did not. Thus, melatonin mediates endometrial epithelial apoptosis through the MT receptors and also by regulating estrogen function. This study provides evidence of the regulatory mechanism of melatonin on the physiological function of the sheep uterus.

Therapeutic effect of human umbilical cord-derived mesenchymal stem cells on injured rat endometrium during its chronic phase

BACKGROUND

Repair deficiency after endometrial injury is an important reason for intra-uterine adhesions, amenorrhea, and infertility in females. Bone marrow-derived mesenchymal stem cell (BMSC) transplantation is effective in repairing the damaged endometrium. However, the possibility of using umbilical cord-derived MSCs (UC-MSCs) to treat endometrial injury is rarely reported.

METHODS

Ethanol (95%) was injected into rat uterus to establish a model of endometrial injury. UC-MSCs were injected through the tail vein, either as a single, twice, or thrice administration. Functional restoration of the uterus was assessed by testing embryo implantation rates. Endometrial morphological alteration was observed by hematoxylin and eosin staining. Endometrial fibrosis, markers of epithelial and stromal cells of endometrium, cell proliferation and angiogenesis, and inflammatory factors were detected using immunohistochemistry, Western blotting, and quantitative reverse-transcription polymerase chain reaction.

RESULTS

Endometrial morphology and embryo implantation rates were significantly improved on day 8 of transplantation among single-, twice-, or thrice-administered rats. Moreover, UC-MSCs could alleviate fibrosis in general, and reduced the expression of fibrosis markers, α-smooth muscle actin (α-SMA) and transforming growth factor (TGF)-β. The cell proliferation marker Ki-67 had a positive expression in the injured endometrium after UC-MSC transplantation. The endometrial stromal marker vimentin and epithelial marker cytokeratin-19 (CK-19) expressions were visibly increased. The expression of vascular markers CD31, vascular endothelial growth factor (VEGF)A, and matrix metalloprotein (MMP)9 was generally upregulated. Proinflammatory factors interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and interleukin (IL)-2 were significantly downregulated in the rats administered UC-MSCs twice and thrice.

CONCLUSIONS

UC-MSC transplantation contributed to the repair of endometrial injury and restoration of fertility, likely through the suppression of excessive fibrosis and inflammation, and enhancement of endometrial cell proliferation and vascular remodeling.

Prediction of ovarian function in premenopausal breast cancer patients with amenorrhoea after chemotherapy: a simple clinical score

We evaluated a non-invasive method for predicting the ovarian function of premenopausal breast cancer patients with amenorrhoea after chemotherapy. A total of 34 patients had ovarian function, whereas 56 had no ovarian function. Logistic regression analysis indicated that age (P = 0.034; hazards ratio [HR], 0.29; confidence interval [CI], 0.091–0.910), follicle-stimulating hormone (P = 0.032; HR 0.97; CI 0.944–0.997) and oestradiol (P = 0.047; HR 1.01; CI 1.000–1.015) were independent influencing factors that determine ovarian function. The ovarian function score (OFS) (P < 0.001; HR 48.00; CI 10.174–226.452) was obtained through a comprehensive analysis of these three variables, and it could more effectively predict ovarian function. According to receiver operating characteristic curve analysis, the OFS had the highest values compared with the other three variables (sensitivity, 94.6 %; specificity, 79.3 %). The OFS is simple and easy to use; thus, it is expected to become a new method for determining drug-induced amenorrhoea in women with breast cancer. Ovarian function likely still exists if the OFS is ≤1.

Comparative Study of Tamoxifen and Raloxifene on Endometrial Cell Proliferation of Female Rats in Persistent Estrus

Objective

The objective of the study was to compare the effect of tamoxifen and raloxifene on the endometrium of female rats in persistent estrus, by Ki-67 protein expression.

Methods

The study comprised 60 Wistar-Hannover female rats in persistent estrus, induced by a single subcutaneous dose of 1.25 mg of testosterone propionate on the second day of age. At 90 days of life, the animals were randomly divided into 3 groups of 20 animals each. Group 1 (control), received only placebo; group 2, the animals were treated with tamoxifen, 250 μg/d; and group 3, the rats were treated with 750 μg/d of raloxifene by gavage during 30 days. Then, the animals were killed, and the endometrium was removed for immunohistochemical analysis of Ki-67 antigen expression. Statistical analysis was performed by β regression model (P < 0.05).

Results

Mean percentages of Ki-67 protein expression in the endometrium of rats in persistent estrus were 43.21% ± 3.39%, 7.36% ± 0.95%, and 7.20% ± 0.76% in groups 1, 2 and 3, respectively (P < 0.001). There was no statistical difference between groups 2 and 3 (P = 0.7159).

Conclusions

The present results indicate that, at the doses and during the time of treatment used, both tamoxifen and raloxifene induce atrophy in a similar way of endometrial epithelium of rats in persistent estrus.

RAD001 (Everolimus) Can prevent tamoxifen-related endometrial and stromal hyperplasia

The mechanism of tamoxifen-associated endometrial hyperplasia and cancer is not elicited. RAD001 inhibits a target protein in phosphatidyl kinase pathway, which is involved in endometrial hyperplasia and cancer. We investigated whether endometrial hyperplasia can be prevented through inhibition of the target of rapamycin by RAD001. Sixty BALB/c mice underwent oophorectomy and were divided into 6 groups: group 1, placebo group; group 2, tamoxifen-treated (4 mg/kg per 24 hours); group 3, estradiol-treated (4 mg/kg per 24 hours); group 4, RAD001-treated (1.5 mg/kg per 24 hours); group 5, tamoxifen (4 mg/kg per 24 hours)-and-RAD001 (1.5 mg/kg per 24 hours)-treated; and group 6, estradiol (4 mg/kg per 24 hours)-and-RAD001 (1.5 mg/kg per 24 hours)-treated. The count of glands, the length of epithelium, and immunohistochemical staining of proliferating cell nuclear antigen were analyzed. The count of total glands and the epithelial length were 30.8 (7.1) and 126 (43.4) microm, 53 (8.1) and 162.5 (34.8) microm, 65.2 (13.6) and 401.4 (44.0) microm, and 82.0 (5.2) and 444.7 (57.8) microm in the placebo-, the RAD001-, the tamoxifen-, and the estradiol-treated groups, respectively (P < 0.05). Although addition of RAD001 to estradiol did not decrease the count of total glands and the epithelial length, addition of RAD001 to tamoxifen did (43.3 [13.3] and 218.0 [29.2] microm, P < 0.05). The immunoreactive score of proliferating cell nuclear antigen is significantly decreased by the addition of RAD001 to either tamoxifen or estradiol in the epithelial and glandular cells. RAD001 can prevent tamoxifen-associated and estrogen-related endometrial hyperplasias in mice. RAD001 also decreases stromal cell proliferation in the tamoxifen-treated mice.

Effects of metformin on mammalian target of rapamycin in a mouse model of endometrial hyperplasia

OBJECTIVE

The effects of metformin on S6K1, which is a crucial effector of mTOR signaling, and on endometrium were studied in a mouse model of endometrial hyperplasia induced by unopposed estradiol or tamoxifen.

STUDY DESIGN

Forty-eight oophorectomized Balb/c mice were randomly assigned to receive saline, tamoxifen citrate (4 mg/kg), 17-beta estradiol hemihydrate (4 mg/kg), metformin (50 mg/kg), tamoxifen citrate (4 mg/kg) with metformin (50 mg/kg), or estradiol (4 mg/kg) with metformin (50 mg/kg) for 3 days. Histological markers of uterotrophy, including luminal epithelial cell height and density of endometrial glands were quantified for each slide. Immunohistochemical expression of PCNA and S6K1 was evaluated. H-score was used for S6K1 expression. Statistical analysis was performed using Student's t-test for comparison of two continous variables and one-way ANOVA for comparison of multiple variables.

RESULTS

Mice treated either with tamoxifen or estradiol had significantly increased density of endometrial glands and epithelial heights compared to vehicle-only or metformin-only group (p<0.001). Addition of metformin to tamoxifen or estradiol treated mice significantly decreased the density of endometrial glands and epithelial cell heights (p<0.05). Addition of metformin to tamoxifen significantly decreased the H-score of S6K1 (p<0.05) and the immunohistochemical expression of PCNA (p<0.05) in uterine lining epithelium, glandular and stromal cells. Addition of metformin to estradiol significantly decreased the H-score of S6K1 (p<0.05) and the immunohistochemical expression of PCNA (p<0.05) in uterine lining epithelium, glandular and stromal cells.

CONCLUSION

Metformin seems to have possible antiproliferative effects on the endometrium of estradiol or tamoxifen treated mice via inhibiting the mTOR mediated S6K1 activation.

Vascular endothelial growth factor expression in the urethral epithelium of castrated adult female rats treated with tamoxifen

OBJECTIVE

The aim of this study was to evaluate the effects of tamoxifen on vascular endothelial growth factor (VEGF) expression in the urethral epithelium of castrated rats.

MATERIALS AND METHODS

Thirty-six adult, castrated, female Wistar-Hannover rats were randomly divided into two groups: group I (n = 16, control), receiving only propylene glycol, and group II (n = 20, tamoxifen), treated with 250 microg/day of tamoxifen for 30 consecutive days by gavage. On the 31st day, the animals were sacrificed and the urethras were immediately removed, separated into the proximal and distal segments and processed for VEGF immunohistochemistry. The data were analysed using Student's t-test (p < 0.05).

RESULTS

The mean percentage of VEGF expression in the epithelium of the proximal urethra of the animals in groups I and II was 64.47+/-3.70 and 74.69+/-3.03, respectively (p < 0.03), whereas the mean percentage of VEGF expression in the distal urethral epithelium of the animals in groups I and II was 53.49+/-4.64 and 68.57+/-3.67, respectively (p < 0.01).

CONCLUSIONS

Our results indicate that, at the dose and during the time of treatment used, tamoxifen increased VEGF expression in the urethral epithelium of castrated rats.