Leflunomide—an Immunomodulator—Induces Regression of Endometrial Explants in a Rat Model of Endometriosis

Pingchong Jiangni recipe through nerve growth factor/transient receptor potential vanilloid 1 signaling pathway to relieve pain in endometriosis model rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pingchong Jiangni recipe (PJR) is often used in the treatment of endometriosis (EM). This formula has been clinically validated by the State Administration of Traditional Chinese Medicine Key Specialties Collaborative Group for its therapeutic efficacy. Recently, our research team also confirmed that PJR has a shrinking effect on ovarian chocolate cysts. Additionally, PJR was also found to have a shrinking effect on EM lesions; however, the mechanism by which this effect occurs remains unclear.

AIM OF THE STUDY

To explore the mechanisms by which PJR relieves pain in patients with EM.

MATERIALS AND METHODS

A rat model of EM was established by autologous transplantation. PJR (3.78 g/kg, 7.56 g/kg, and 15.12 g/kg) was orally administered for 21 days. The rat grimace scale (RGS) score and paw withdrawal threshold (PWT) were measured at a fixed time during the experiment. Hematoxylin and eosin staining was performed to observe histopathological changes in EM rats after administration, enzyme-linked immunosorbent assay to evaluate the plasma expression of tumor necrosis factor-α (TNF-α) and nerve growth factor (NGF), and immunohistochemistry and western blotting to identify differences in the expression of pain-related factors in EM rats.

RESULTS

The medium-dose group of PJR (7.56 g/kg) had the best effect on relieving pain in EM rats by reducing RGS, increasing PWT, reducing the ectopic endometrium, improving the cellular structure of the lesion, and reducing TNF-α and NGF levels. However, PJR significantly decreased the expression of transient receptor potential vanilloid 1 (TRPV1), phosphorylated TRPV1 (p-TRPV1), protein kinase C (PKC), and NGF.

CONCLUSION

The mechanism by which PJR relieves EM pain may be through the downregulation of NGF, PKC, and TRPV1 expression.

The effects of Rituximab on experimental endometriosis model in rats

AIM

Endometriosis is a common, chronic benign gynecologic disease and distresses women in their reproductive age. Yet the pathogenesis of endometriosis is not clear, multifactorial mechanisms have been characterized for the initiation, progression, and regression of this disease. It has been suggested that immune cells in the lymphoid lineage play essential roles in accepting or rejecting the survival, implantation, and proliferation of endometrial and endometriotic cells and, dysfunction of B-lymphocytes (B-cells) are one of the major causes for the progression of endometriosis. In this study, we aimed to evaluate the potential therapeutic efficacy of Rituximab, an inhibitor for B-cells, for endometriosis in an experimental animal model.

METHODS

Experimental endometriosis animal model has been utilized using mature female rats. Rats underwent surgery to initiate endometriosis on the abdominal wall. After confirming for endometriosis, rats were treated with either Rituximab or saline solution. After 14 days of treatment, implants were dissected, and evaluated for volumes and histological features. Anti-CD-20 antibody was used for immunohistochemistry scoring purposes.

RESULTS

There is significant decrease in the volume of endometriotic implants after treatment with Rituximab (188.81 ± 149.42 vs 20.37 ± 13.08, p = 0.001). There are also significant differences for the B-cell count and fibrosis score between the control and treatment groups (3.08 ± 2.6 vs 1.56 ± 1.42., p = 0.043).

CONCLUSION

In an experimental rat endometriosis model, we assessed Rituximab, an antibody for B-lymphocyte, as a candidate medical treatment for endometriosis. Additional studies are required to further evaluate the effects of Rituximab on the prevention of endometriosis.

Role of AMPK/mTOR, mitochondria, and ROS in the pathogenesis of endometriosis

Endometriosis is the presence of endometrial tissue outside the uterine cavity usually in the ovaries, fallopian tube, and pelvic cavity. It's a chronic enigmatic gynecological condition associated with dysmenorrhea, dyspareunia, pelvic pain, and infertility. Endometriosis lesions exist in a unique microenvironment characterized by increased concentrations of hormones, inflammation, and oxidative stress. This environment promotes cell survival through the binding of membrane receptors and subsequent cascading activation of intracellular kinases that stimulate a cellular response. In endometriosis, well-established signaling pathways, mTOR and AMPK, are altered via steroid hormones and other factors to promote cell growth, migration, and proliferation. This is accompanied by dysfunction in the mitochondria that increase energy production to sustain proliferation demands consequently leading to reactive oxygen species overproduction. This review aims to summarize the role of altered mTOR/AMPK signaling pathway, mitochondrial dysfunction, and reactive oxygen species overproduction along with providing therapeutic and diagnostic approaches. Highlighting these factors would provide a better understanding to reach a coherent theory for the pathogenesis of endometriosis.

Effects of ranibizumab and zoledronic acid on endometriosis in a rat model

PURPOSE

To investigate the histological efficacy of ranibizumab and zoledronic acid in an experimentally induced endometriosis model as compared with danazol, buserelin acetate and dienogest.

METHODS

Endometrial implants were introduced in 52 female Wistar albino rats, which were then randomly divided into six groups. The animals were, respectively, given dienogest, danazol, buserelin acetate, zoledronic acid, ranibizumab and 0.9% NaCl. After 4 weeks, the volumes and histopathological properties of the implants were evaluated and the implants were excised completely at the third laparotomy. A histopathological scoring system was used to evaluate the preservation of epithelia. Endometrial explants were evaluated immunohistochemically.

RESULTS

Among the groups, the histological score was significantly lower in the zoledronic acid and ranibizumab groups compared with the controls (p < 0.001). There were no significant differences regarding ellipsoidal volume levels between groups (p > 0.05). However, there was a statistically significant difference regarding cell numbers according to the degree of Bcl-2, NF-κB, and CD31 staining (p < 0.001). There was no statistically significant difference in Bcl-2, CD31, or NF-κB staining in the binary comparisons between the other groups (p > 0.05). For Bcl-2 staining, the staining rate of the group treated with zoledronic acid was significantly lower compared with the dienogest and danazol groups (p < 0.05). The staining rates of CD31 and NF-κB were significantly lower in the zoledronic acid and ranibizumab groups compared with the controls (p < 0.05).

CONCLUSION

According to these results, zoledronic acid and ranibizumab may be putative candidates for the treatment of endometriosis.

Peritoneal Fluid Cytokines Reveal New Insights of Endometriosis Subphenotypes

Endometriosis is a common inflammatory gynecological disorder which causes pelvic scarring, pain, and infertility, characterized by the implantation of endometrial-like lesions outside the uterus. The peritoneum, ovaries, and deep soft tissues are the commonly involved sites, and endometriotic lesions can be classified into three subphenotypes: superficial peritoneal endometriosis (PE), ovarian endometrioma (OE), and deep infiltrating endometriosis (DIE). In 132 women diagnosed laparoscopically with and without endometriosis (n = 73, 59 respectively), and stratified into PE, OE, and DIE, peritoneal fluids (PF) were characterized for 48 cytokines by using multiplex immunoassays. Partial-least-squares-regression analysis revealed distinct subphenotype cytokine signatures—a six-cytokine signature distinguishing PE from OE, a seven-cytokine signature distinguishing OE from DIE, and a six-cytokine-signature distinguishing PE from DIE—each associated with different patterns of biological processes, signaling events, and immunology. These signatures describe endometriosis better than disease stages (p < 0.0001). Pathway analysis revealed the association of ERK1 and 2, AKT, MAPK, and STAT4 linked to angiogenesis, cell proliferation, migration, and inflammation in the subphenotypes. These data shed new insights on the pathophysiology of endometriosis subphenotypes, with the potential to exploit the cytokine signatures to stratify endometriosis patients for targeted therapies and biomarker discovery.

The beneficial effects of nerolidol and hesperidin on surgically induced endometriosis in a rat model. Gynecol Endocrinol 2018;34:975-980. [PMID: 29734842 DOI: 10.1080/09513590.2018.1469611]

The objective of this article is to analyze the effects of nerolidol and hesperidin treatment on surgically induced endometriosis in a rat model. Endometriosis was induced in 24 healthy adult female Wistar albino rats via homologous uterine horn transplantation. Three operations were performed on each rat. After the second operation, the rats were randomized into control, nerolidol, and hesperidin treatment groups, and medications were administered for 2 weeks. The effects of the drugs on the endometriotic foci were evaluated after the third operation. Compared with the endometriosis control group, the average volume of the lesions was significantly lower in rats treated with hesperidin and nerolidol. Malondialdehyde levels were significantly reduced in the nerolidol-treated group, and glutathione levels and superoxide dismutase activity were significantly elevated in the endometriotic foci of both the hesperidin- and nerolidol-treated groups compared with the endometriosis group. Hesperidin and nerolidol treatment also improved histological parameters, such as hemorrhage, vascular congestion, necrosis, and inflammatory cell infiltration in the endometriotic foci. The results of this study demonstrated that treatment with the potent antioxidants nerolidol and hesperidin caused a significant regression of surgically induced endometriotic foci in rats.

Chronic Niche Inflammation in Endometriosis-Associated Infertility: Current Understanding and Future Therapeutic Strategies

Endometriosis is an estrogen-dependent inflammatory disease that affects up to 10% of women of reproductive age and accounts for up to 50% of female infertility cases. It has been highly associated with poorer outcomes of assisted reproductive technology (ART), including decreased oocyte retrieval, lower implantation, and pregnancy rates. A better understanding of the pathogenesis of endometriosis-associated infertility is crucial for improving infertility treatment outcomes. Current theories regarding how endometriosis reduces fertility include anatomical distortion, ovulatory dysfunction, and niche inflammation-associated peritoneal or implantation defects. This review will survey the latest evidence on the role of inflammatory niche in the peritoneal cavity, ovaries, and uterus of endometriosis patients. Nonhormone treatment strategies that target these inflammation processes are also included. Furthermore, mesenchymal stem cell-based therapies are highlighted for potential endometriosis treatment because of their immunomodulatory effects and tropism toward inflamed lesion foci. Potential applications of stem cell therapy in treatment of endometriosis-associated infertility in particular for safety and efficacy are discussed.

Vitamin C is effective for the prevention and regression of endometriotic implants in an experimentally induced rat model of endometriosis

OBJECTIVE

Endometriosis is a chronic inflammatory disease pathologically defined as the presence of endometrial-like tissue outside the uterine cavity. It is one of the most important diseases affecting women of reproductive age. The process of endometriotic implant growth is mediated by many complex interactions of immunologic, hormonal, genetic, and environmental mediators. Vitamin C (ascorbic acid), besides playing a role in preventing invasion and metastasis, is an antioxidant having anti-inflammatory and -angiogenic effects. In this study, we aimed to investigate the effect of vitamin C on the prevention and regression of endometriotic implants in a rat model of endometriosis.

MATERIALS AND METHODS

This was a prospective, comparative, experimental animal study. After endometriotic implants were induced simultaneously, rats were divided into three groups. Group A was given 500 mg/kg of intravenous vitamin C every 2 days, starting immediately after implantation (n = 11). All rats had a second operation 21 days after the initial one and had the lesion volumes measured. Group B was given 500 mg/kg of intravenous vitamin C every 2 days, starting 21 days after this operation (n = 11). All rats were sacrificed 21 days after the third operation. Implant volume, weight measurements, and histopathological evaluation of the lesions were carried out. Group A received vitamin C throughout the study, while Group C (n = 11) was not given any medication. The findings in the three groups were compared.

RESULTS

At the second laparotomy after the induction, Group A had the smallest implant volume with a statistically significant difference compared to Group B (p = 0.012). The end-of-study volumes of endometriotic implants of group B were significantly smaller than the first volumes (p < 0.05).

CONCLUSION

Intravenous vitamin C treatment might have a suppressive effect on the prevention of endometriotic implant induction and regression of endometriotic implant volumes.

Evaluation of PLGA containing anti-CTLA4 inhibited endometriosis progression by regulating CD4+CD25+Treg cells in peritoneal fluid of mouse endometriosis model

Our study investigated poly(lactic-co-glycolic acid) (PLGA) as protein delivery vehicles encapsulate CTLA-4-antibody (anti-CTLA-4) which is essential for CD4+CD25+Treg cells suppressive function exposing superior potential for inhibiting endometriosis progress in mouse model than single anti-CTLA-4. Anti-CTLA-4 loaded PLGA combined to ligands CTLA-4 in surface of CD4+CD25+Treg cells which distributed in peritoneal fluid of mouse endometriosis model. The particle size, zeta potential of the anti-CTLA-4 loaded nanoparticles was detected by dynamic light scattering. Morphology of nanoparticles was evaluated by transmission electron microscopy (TEM). Confocal laser scanning microscopy (CLSM) indicated distribution of anti-CTLA-4 with PLGA or without in peritoneal fluid. Cumulative anti-CTLA-4 release from nanoparticles was evaluated by Micro BCA assay. The percentage of CD4+CD25+Treg cells in peritoneal fluid was demonstrated by flow cytometer. In vitro experiment we co-culture ectopic endometrial cells (EEC) with isolated CD4+CD25+Treg cells in peritoneal fluid (PF), proliferation and invasion of ectopic endometrial cells (EEC) was measured by BrdU ELISA assay and Matrigel invasion assay. In comparison with anti-CTLA-4 without nanoparticles, the bioconjugates PLGA/anti-CTLA-4 were tolerated in peritoneal fluid with a controlled release of anti-CTLA-4 in 3, 7, 14days. Moreover, PLGA/anti-CTLA-4 had superior protective regulation ability to reduce level of CD4+CD25+Treg cells in peritoneal fluid. Most strikingly, in vitro experiment, PLGA/anti-CTLA-4 exhibited better ability in inhibiting proliferation and invasion of ectopic endometrial cells in co-culture system compared with anti-CTLA-4. Progressively, PLGA/anti-CTLA-4 had better suppressive activity to inhibited IL-10 and TGF-beta secreted by CD4+CD25+Treg cells which indicating that PLGA/anti-CTLA-4 suppressed cells proliferation and invasion through reduced IL-10 and TGF-beta production. Thus, PLGA/anti-CTLA-4 may be a potential strategy for endometriosis therapy.

Effect of Caffeic Acid Phenethyl Ester on the Regression of Endometrial Explants in an Experimental Rat Model

The objective of this study is to determine the effects of antioxidant and anti-inflammatory caffeic acid phenethyl ester (CAPE) on experimental endometriosis, peritoneal superoxide dismutase (SOD) and catalase (CAT) activities, and malondialdehyde (MDA) levels in the rat endometriosis model. Thirty rats with experimentally induced endometriosis were randomly divided into 2 groups and treated for 4 weeks with intraperitoneal CAPE (CAPE-treated group; 10 micromol/kg/d, n = 13) or vehicle (control group; n = 13). The volume and weight changes of the implants were calculated. Immunohistochemical and histologic examinations of endometriotic explants by semiquantitative analysis and measurements of peritoneal SOD, CAT, and MDA levels were made. Following 4 weeks of treatment with CAPE, there were significant differences in posttreatment spherical volumes (37.4 +/- 14.7 mm(3) vs 147.5 +/- 41.2 mm(3)) and explant weights (49.1 +/- 28.5 mg vs 158.9 +/- 50.3 mg) between the CAPE-treated groups and controls. The mean evaluation nomogram levels in glandular epithelium for COX-2 positivity by scoring system were 2.1 +/- 0.3 in the CAPE-treated group and 3.9 +/- 0.3 in the control group. In the CAPE-treated group, peritoneal levels of MDA and activities of SOD and CAT significantly decreased when compared with the control group (P < .01). Histologic analysis of the explants demonstrated mostly atrophy and regression in the treatment group, and semiquantitative analysis showed significantly lower scores in rats treated with CAPE compared with the control group. CAPE appeared to cause regression of experimental endometriosis.

Adenosine Triphosphate Regresses Endometrial Explants in a Rat Model of Endometriosis

The aim of this study was to determine the effects of adenosine triphosphate (ATP) in a rat endometriosis model. After surgical induction of endometriosis, 3 rats were killed, and explants were measured in the remaining 19 rats, which were then randomly assigned to 4 groups. Group 1 (n = 4) received normal saline (2 mL/d intragastric [IG]), group 2 (n = 4) gestrinone (0.5 mg/kg/d IG), group 3 (n = 5) ATP (3.4 mg/kg/d IG), and group 4 (n = 6) ATP (1.0 mg/kg/d; intramuscularly), respectively. Four weeks after medication, they were euthanized to evaluate histological features of explants and eutopic uterine tissues. To test the effect of ATP on the growth of eutopic endometrium stromal cells, proliferation rates of hEM15A cells at 24, 48, and 72 hours after treatment with different concentrations of ATP and vehicle control were detected with the Cell Counting Kit-8 (CCK-8) method. There was a significant difference between pretreatment and posttreatment volumes within group 2 (positive control; P = .048) and group 4 (P = .044). On condition that pretreatment implant size was similar in both groups (P = .516), regression of explants in group 4 was significantly higher than that in group 1 (negative control; P = .035). Epithelial cells were significantly better preserved in group 1 than in group 3 (P = .008) and group 4 (P = .037). The CCK-8 assay showed no significant difference in proliferation among hEM15A cells treated with ATP and controls. These results suggest that ATP regresses endometriotic tissues in a rat endometriosis model but has no impact on the growth of eutopic endometrium stromal cells.

Human chorionic gonadotropin improves endometriosis through downregulation of leptin expression in rats

OBJECTIVE

To investigate whether and how human chorionic gonadotropin (HCG) treatment ameliorates endometriosis in an endometriotic rat model.

METHODS

Twenty-four endometriosis rats were established and were randomly divided into four groups, and then the rats were treated with 19.4, 25.8, and 51.6 IU/100 g weight/day of HCG, respectively. The control group was treated with 0.9% NaCl. After 15 days (3 estrous cycles), the ectopic lesion volume and the expression of leptin protein in eutopic and ectopic endometrium were investigated.

RESULTS

After HCG treatment, the volumes of endometriotic lesions were significantly smaller than those before treatment. During endometriosis development, the expression of leptin protein in eutopic and ectopic endometrium was remarkably increased. HCG administration reversed leptin upregulation in endometriotic tissues.

CONCLUSION

HCG therapy appears to be an effective treatment for endometriosis in rats through down-regulation of leptin expression in eutopic and ectopic endometrium.

Regression of experimental endometriotic implants in a rat model with the angiotensin II receptor blocker losartan

AIM

Endometriosis is a common disease in women of reproductive age, and many different treatments have been developed, although none has provided a cure. In this study, the efficacy of losartan, an angiotensin II type 1 receptor blocker and an antiangiogenic and anti-inflammatory agent, on regression of experimental endometriotic implants in a rat model was investigated.

METHODS

Peritoneal endometriosis was surgically induced in 16 mature female Sprague-Dawley rats. The peritoneal endometriotic implant was confirmed after 28 days, and the animals were divided randomly into two groups. The control group (n = 8) was given 4 mL/day tap water by oral gavage, and the losartan group (n = 8) was given 20 mg/kg per day losartan p.o. We compared endometriotic implant size, extent and severity of adhesion, as well as plasma and peritoneal lavage fluid cytokine levels including vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF)-α, plasma inflammatory factor pentraxin-3 (PTX-3) and C-reactive protein (CRP) between the treatment groups.

RESULTS

Mean surface endometriotic area, histological score of implants, adhesion formation, plasma VEGF, TNF, PTX-3 and CRP levels were significantly lower in the losartan group compared with control (P < 0.05). Furthermore, the peritoneal VEGF level was lower in the losartan group than in the control group (P < 0.001), but peritoneal TNF-α was similar in both groups (P > 0.05).

CONCLUSION

Losartan suppressed the implant surface area of experimental endometriosis in rats and reduced the levels of plasma VEGF, TNF-α, PTX-3 and CRP.

Melatonin treatment results in regression of endometriotic lesions in an ooferectomized rat endometriosis model

OBJECTIVE

We aimed to determine the effects of melatonin treatment on endometrial implants in an oopherectomized rat endometriosis model.

MATERIAL AND METHODS

This study is a prospective, randomised, controlled experimental study. It was carried out at the Experimental Research Center of Yeditepe University (YUDETAM). Twenty-two, female, non-pregnant, nulligravid Spraque-Dawley albino rats were included in our study. Endometriosis was surgically induced in oopherectomized rats. Rats were randomised into two groups: control group and melatonin group. In the melatonin group, rats were treated with melatonin (20 mg/kg/day) for two weeks. After the operations were performed to assess the regression of the endometriotic lesions, melatonin treatment was stopped. At the end of the sixth week necropsies were performed to assess the rate of recurrence. The volume and histopathological scores of endometriotic foci were examined.

RESULTS

Volumes of the endometriotic lesions significantly decreased in the melatonin group. Also, when the melatonin group was analysed within itself, endometriotic lesion volumes decreased and histopathological scores increased significantly.

CONCLUSION

Melatonin causes regression of the endometriotic lesions in rats and improvement in their histopathological scores.

The effects of ranibizumab on surgically induced endometriosis in a rat model: a preliminary study

OBJECTIVE

To examine the effect of ranibizumab on surgically induced endometriosis in rat models.

STUDY DESIGN

Endometrial tissue was implanted onto the abdominal peritoneum of 20 rats that were randomized into 2 groups. The rats in group 1 (n = 9) were given 0.6 mg/kg ranibizumab on the 1st and 14th days after the second operation. The rats in group 2 (control group, n = 9) received no medication. All the rats were observed for a total of 28 days.

RESULTS

At the end of the treatment, the mean volume and weight of the explants in group 1 (11.49 ± 6.87 mm(3) and 36.61 ± 17.84 mg) were significantly lower than that of the control group (190.6 ± 177.4 mm(3) and 187.3 ± 174.5 mg; both Ps < .01). Mean epithelial histologic scores were significantly lower in group 1 (1.11 ± 0.78) than that of the control group (2.33 ± 0.71; P < .01). When compared with the control group, vascular endothelial growth factor (VEGF) immunoreactivities in group 1 showed statistically significant reductions (1.67 ± 0.50; 2.67 ± 0.50; P < .01).

CONCLUSION

Ranibizumab has significantly regressed the size of the endometriotic implants and caused atrophy of these lesions in rats by decreasing explant levels of VEGF.

Somatostatin analogs regress endometriotic implants in rats by decreasing implant levels of vascular endothelial growth factor and matrix metaloproteinase 9

OBJECTIVE

To examine the effect of somatostatin analogs on surgically induced endometriosis in rat models.

STUDY DESIGN

Endometrial tissue was implanted onto the abdominal peritoneum of 26 rats that were randomized into 3 groups. The rats in group 1(n = 9) were subcutaneously administered with 0.02 mg/kg/d of octreotide (a short-acting analog)for 28 days . The rats in group 2 (n = 8) were subcutaneously injected with 20 mg/kg of a single dose of a long-acting analogue lanreotide The rats in group 3 were given no medication and served as controls (n = 9).

RESULTS

Mean volume and histologic score of implants in groups 1 (P < .01 and P < .05, respectively) and 2 (P < .01and P < .05, respectively) were significantly lower than that in group 3. There were significant reductions in vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP-9) immunoreactivities in group 1 (0.67 ± 0.50 and 1.22 ± 0.44, respectively; both P < .01) and group 2 (0.71 ± 0.48 and 0.86 ± 0.69, respectively; both P < .01) when compared with the control group (1.78 ± 0.83 and 2.11 ± 0.78, respectively).

CONCLUSION

Somatostatin analogs has regressed significantly the size of the endometriotic implants and caused atrophy of these lesions in rats by decreasing explant levels of VEGF and MMP-9.

Effects of pinealectomy and melatonin supplementation on endometrial explants in a rat model

OBJECTIVE

To determine the effects of pinealectomy on endometrial explants in rats and evaluate the activity of superoxide dismutase (SOD) and catalase (CAT) and the levels of malondialdehyde (MDA) in the rat endometriosis model.

STUDY DESIGN

Rats with experimentally induced endometriosis were randomly divided into three groups after second-look laparotomies. Group 1 (pinealectomy, n = 8) and Group 2 (pinealectomy+melatonin, n = 8) underwent pinealectomies after the second-look laparotomies. Group 3 was presented as control group (vehicle solution+without pinealectomy (n = 6)). Melatonin was administered intraperitoneally for 4 weeks in Group 2, whereas an equal volume of vehicle solution was given to Groups 1 and 3. Evaluation of the volume of the endometrial explants, histopathological examination and preservation of explant epitheliums according to the scoring system were undertaken.

RESULTS

There was a statistically significant increase in spherical explant volumes of Group 1 compared to Groups 2 and 3. In Group 1, the level of MDA was significantly higher and SOD and CAT activity was significantly lower compared to Groups 2 and 3. A statistically significant increase in the epithelial lining scores of explants was noted in Group 1 compared to Groups 2 and 3.

CONCLUSION

The effects of pinealectomy on the progression of endometriosis explants were reversed by melatonin.

Metformin regresses endometriotic implants in rats by improving implant levels of superoxide dismutase, vascular endothelial growth factor, tissue inhibitor of metalloproteinase-2, and matrix metalloproteinase-9

OBJECTIVE

We sought to test if metformin could regress endometriotic explants in rats.

STUDY DESIGN

After inducing endometriotic implants and randomization of female Wistar albino rats, they were given 25 and 50 mg/kg/day of oral metformin in group A (n = 9) and B (n = 8), respectively, for 28 days. Group C (n = 9) was given saline as placebo.

RESULTS

Mean volume, weight, and histologic score of implants in groups A (P < .01, P < .05, and P < .05, respectively) and B (P < .01, P < .05, and P < .05, respectively) were significantly lower than in group C. The activity of superoxide dismutase and tissue inhibitor of metalloproteinase-2 staining in groups A (P < .05 and P < .01, respectively) and B (P < .01 and P < .01, respectively) was significantly higher than in the control group. Moreover, there were more significant reductions in implant levels of vascular endothelial growth factor and matrix metalloproteinase-9 in groups A (both P < .001) and B (both P < .001) than in group C.

CONCLUSION

Metformin causes regression of endometriotic implants in rats.

The effects of letrozole and melatonin on surgically induced endometriosis in a rat model: a preliminary study

OBJECTIVE

To determine the effects of letrozole and melatonin on surgically induced endometriosis in a rat endometriosis model.

DESIGN

Prospective, randomized, controlled, experimental study.

SETTING

Experimental Research Center of Yeditepe University (YUDETAM).

ANIMAL(S)

Thirty female, nonpregnant, nulligravid Wistar-Hannover albino rats.

INTERVENTION(S)

Surgical induction of endometriosis, administration of estrogen for 2 weeks, and laparotomy; administration of letrozole or melatonin for 2 weeks after induction of endometriosis, and laparotomy; administration of estrogen for 2 weeks and necropsy.

MAIN OUTCOME MEASURE(S)

The volume and histopathologic scores of endometriotic foci, and levels of superoxide dismutase, catalase, and malondialdehyde in the peritoneal fluid.

RESULT(S)

The mean volumes of the endometriotic foci were 99.6 +/- 18.8 mm(3), 21.5 +/- 7.4 mm(3), and 29.2 +/- 17.5 mm(3), and histopathologic scores were 2.5 +/- 0.7, 2.0 +/- 0.8, and 1.7 +/- 0.9 in the melatonin group at the end of the second, fourth, and sixth weeks, respectively. The mean volumes of the endometriotic foci were 75.9 +/- 26.3 mm(3), 29.8 +/- 14.7 mm(3), and 121.2 +/- 35.1 mm(3) and the histopathologic scores were 2.5 +/- 0.5, 2.2 +/- 0.8, and 2.7 +/- 0.4 in the letrozole group at the end of the second, fourth, and sixth weeks, respectively. In the melatonin group, peritoneal fluid superoxide dismutase and catalase levels increased statistically significantly.

CONCLUSION(S)

Melatonin caused more pronounced regression of endometriotic foci when compared with letrozole in a rat model. After the cessation of melatonin treatment, the recurrence rate was lower than that observed after the cessation of letrozole treatment.

New drugs in development for the treatment of endometriosis

Endometriosis is a common and enigmatic disease causing pelvic pain and infertility. Current treatment is mainly based on the use of surgery and ovarian suppressive agents. There is in particular the need for new therapeutic options able to allow a normal menstrual cycle to occur and also consent pregnancy. In the present review, we aimed to give a concise and practical overview in order to allow the clinician to clearly understand the level of development of these drugs. We have presented only treatments supported by in vivo researches with a special attention to studies in humans. Results show appealing new possibilities are emerging from agents counteracting the endometriosis-associated inflammation. Recent data also suggests that there is still the opportunity to refine the use of already available agents.

The broad-spectrum chemokine inhibitor NR58-3.14.3 suppresses the implantation and survival of human endometrial implants in the nude mice endometriosis model

Many chemokines likely contribute to the pathogenesis of endometriosis. The authors hypothesize that the broad-spectrum chemokine inhibitor NR58-3.14.3 may prevent ectopic human endometrium implantation and growth. After placing human endometrium fragments into the peritoneal cavity, ovariectomized athymic nude mice (n = 31) receiving intramuscular estradiol valerate were randomly assigned to daily intraperitoneal injections of either phosphate-buffered saline or NR58-3.14.3. Fourteen days later, the implant number and volume, proliferating cell nuclear antigen (PCNA) and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) index, and MTT cell viability were assessed in the implants. NR58-3.14.3 reduced the total number (45%) and total volume (81%) of endometriotic lesions (P < .05) and revealed a lower PCNA and higher TUNEL index in ectopic implants compared with controls (P < .05). NR58-3.14.3 treatment did not affect endometrial cell proliferation in vitro. NR58-3.14.3, by possibly regulating cell survival, can reduce the number and size of ectopic implants in vivo, supporting the potential use of chemokine inhibitors in novel therapies for endometriosis.

The effect of intraperitoneal interleukin-2 on surgically induced endometriosis in rats

OBJECTIVE

To evaluate the effect of interleukin-2 (IL-2) on an experimental model of endometriosis.

STUDY DESIGN

Double blind and randomized experimental prospective placebo-controlled study. Experimental endometriosis was induced in 66 three-month-old female Wistar rats, by auto-transplanting fragments of endometrium to the peritoneum. After four weeks, the size of each implant was measured in millimeters by laparotomy (L2), and animals were randomly distributed for intraperitoneal administration of human-IL-2, rat-IL-2 or placebo. Four weeks later, the implants were measured (L3) and a second dose was given. After four weeks, endometriosis size was evaluated again (L4).

RESULTS

We found a reduction of experimental endometriosis at L3 that was only significant in IL-2 treated groups: 20.1% and 30.3% with human-IL-2 and rat-IL-2, respectively (p<0.001 with respect to L2 size), versus a non-significant reduction of 9.0% found in placebo group, but the differences were not statistically significant between groups. The decrease after a second dose (L4) was: 49.8%, 41.8% and 11.4% with human-IL-2, rat-IL-2 and placebo, respectively (p<0.001 in IL-2 groups versus L2 and L3, and p<0.05 in both groups versus placebo at L4).

CONCLUSION

Intraperitoneal administration of IL-2 reduces experimental endometriosis, and this effect is similar using rat-IL-2 or human IL-2 (non specie-specific effect).

2D-QSAR and HQSAR of the inhibition of calcineurin-NFAT signaling by blocking protein-protein interaction with N-(4-oxo-1(4H)-naphthalenylidene)benzenesulfonamide analogues

The inhibition of calcineurin-NFAT signaling by blocking protein-protein interaction with N-(4-oxo-1(4H)-naphthalenylidene)benzenesulfonamide analogues was studied in order to obtain mechanistic information about the effects of structural modification and molecular design of immunomodulation agents. The study was carried out by quantitative structure-activity relationship (QSAR) analysis using 2D-QSAR and hologram QSAR (HQSAR) methods. The statistical results of the two models showed the best prediction and fitness (r2 > 0.900) for the inhibition activities. The inhibitory activities from the 2D-QSAR models were dependent upon the electronic affinity of electron acceptor and optimum dipole moment (DM opt = 4.491 Debye). In addition, the HQSAR model provided information about which structural distinctions could be significant contributors the inhibition.

Regression of endometrial explants in a rat model of endometriosis treated with melatonin

OBJECTIVE

To determine the antioxidant, antiinflammatory, and immunomodulatory effects of melatonin on endometrial explants, the distribution of cyclooxygenase-2 (COX-2), the activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and levels of malondialdehyde (MDA) in the rat endometriosis model.

DESIGN

Prospective, placebo-controlled experimental study.

SETTING

Experimental surgery laboratory in a university department.

ANIMAL(S)

Twenty-five rats with experimentally induced endometriosis.

INTERVENTION(S)

Endometriosis was surgically induced in 25 rats by transplanting an autologous fragment of endometrial tissue onto the inner surface of the abdominal wall. Four weeks later, three rats were killed and the remaining 22 rats given second-look laparotomies to identify and measure ectopic uterine tissue in three dimensions. After the second laparotomy, 4 weeks of vehicle and melatonin treatment were administered, then all of the rats were given a third laparotomy and killed.

MAIN OUTCOME MEASURE(S)

The volume and weight of the implants were measured. The remaining rats were randomly divided into two groups. In control group (group 1; n = 11) no medication was given. To the rats in melatonin-treated group (group 2; n = 11), 10 mg/kg a day of melatonin was administered intraperitoneally. Four weeks later, after the second laparotomy, the endometrial explants were reevaluated morphologically, and COX-2 expression was evaluated immunohistochemically and histologically. In addition, endometrial explants were analyzed for the antioxidant enzymes SOD, CAT, and MDA, a marker of lipid peroxidation. A scoring system was used to evaluate expression of COX-2 and preservation of epithelia.

RESULT(S)

The pretreatment and posttreatment volumes within the control group were 135.9 +/- 31.5 and 129.4 +/- 28.7, respectively. The mean explant volume was 141.4 +/- 34.4 within the melatonin group before the treatment and 42.9 +/- 14.0 after 4 weeks of treatment. There was a statistically significant difference in spherical volumes (129.4 +/- 28.7 versus 42.9 +/- 14.0 mm(3)) of explant weights (155.8 +/- 27.1 versus 49.6 +/- 19.5 mg) and COX-2 positivity (91% versus 18.1%) between groups after the third laparotomy. In the melatonin-treated group, the endometrial explant levels of MDA statistically significantly decreased and activities of SOD and CAT significantly increased when compared with the control group. The epithelia showed statistically significantly better preservation in the control group when compared with the melatonin-treated group (2.54 +/- 0.52 versus 0.63 +/- 0.50).

CONCLUSION(S)

Melatonin causes regression and atrophy of the endometriotic lesions in rats.