The effect of a levonorgestrel-releasing intrauterine device on human endometrial oestrogen and progesterone receptors after one year of use

The levonorgestrel-releasing intrauterine device is related to early emotional reactivity: An ERP study

Despite the evidence of altered emotion processing in oral contraceptive (OC) users, the impact of hormonal intrauterine devices (IUD) on emotional processing remains unexplored. Our study aimed to investigate how behavioural performance and event-related potentials (ERPs) linked with emotion reactivity and its regulation are associated with hormonal profiles of women using different types of hormonal contraception and naturally cycling women. Women using OCs (n = 25), hormonal IUDs (n = 33), and naturally cycling women in their early follicular (NCF, n = 33) or mid-luteal (NCL, n = 28) phase of the menstrual cycle were instructed to view emotional pictures (neutral, low and high negativity) and use cognitive reappraisal to up- or down-regulate negative emotions, while their electroencephalogram was recorded. Participants rated perceived negativity after each picture and their emotional arousal throughout the task. Saliva samples were collected to assess levels of 17β-estradiol, progesterone, and testosterone. As expected, emotional arousal increased throughout the task and correlated positively with perceived negativity. Perceived negativity and the amplitudes of the middle (N2/P3) and later (LPP) latency ERP components increased with increasing stimuli negativity. Emotion regulation modulated perceived negativity and the amplitudes of very late ERP components (parietal and frontal LPP). Moreover, IUD-users showed a higher negative amplitude of the frontal N2 in comparison to all three other groups, with the most consistent differences during up-regulation. Finally, testosterone correlated positively with the N2 peak in IUD-users and NCL women. Overall, our findings suggest that IUD-use and testosterone might be related to altered preconscious processing during the emotion regulation task requiring attention to the stimulus. The study underscores the need for additional research into how different hormonal contraceptives are linked to socio-emotional functioning.

The levonorgestrel-releasing intrauterine device induces endometrial decidualisation in women on tamoxifen

There is conflicting literature on whether the levonorgestrel-releasing intrauterine system (LNG-IUS; Mirena^®) induces decidualisation in the tamoxifen-treated endometrium. The expression of the decidualisation marker IGFBP-1 was measured using immunohistochemistry in endometrial biopsies and in serum (using ELISA) of 20 postmenopausal women at the start of tamoxifen-treatment for breast cancer. Ten women were then fitted with LNG-IUS and the other ten received tamoxifen-treatment only and acted as controls. Samples were taken at baseline and after 12 months. At baseline, all endometrial samples were negative for IGFBP-1 and at 12 months, IGFBP-1 was only expressed in the endometria of women fitted with the LNG-IUS, confirming the observed histological features of decidualisation. By contrast, serum IGFBP-1 concentrations were increased by tamoxifen, but not in the group receiving LNG-IUS. In conclusion, tamoxifen induces a rise in serum IGFBP-1 suggesting a systemic, possibly hepatic effect, whilst LNG abrogates this in both the liver and endometrium. Impact statement What is already known on this subject? Previous reports of the use of LNG-IUS in women on tamoxifen have provided conflicting evidence as to whether the endometrium exhibited decidualisation or not. These reports were however based solely on histological examination and lacked supporting biochemical data. What do the results of this study add? After 12 months of treatment with LNG-IUS, the endometria of women on tamoxifen show histological features of decidualisation and the presence of the decidualisation marker IGFBP-1, suggesting that levonorgestrel protects the tamoxifen-treated uterus from additional pathology by causing decidualisation. Serum levels of IGFBP-1 were expected to be a reflection of uterine production, but contrary to expectations, higher levels were identified in women on tamoxifen alone. These data suggest that an inhibition of tamoxifen-induced serum IGFBP-1 production (possibly from a hepatic source) by LNG-IUS occurred and indicates independent systemic effects of both drugs in post menopausal breast cancer patients. What are the implications of these findings for clinical practice and/or further research? This research demonstrated a mechanism for endometrial protection in women on tamoxifen. It also alerts clinicians to the fact that both tamoxifen and LNG-IUS exert systemic effects in this patient group.

Impact of the Levonorgestrel-Releasing Intrauterine System on the Progression of Chlamydia trachomatis Infection to Pelvic Inflammatory Disease in a Baboon Model

Background

Understanding the relationship between the levonorgestrel (LNG)-releasing intrauterine system (IUS) and sexually transmitted infections (STIs) is increasingly important as use of the LNG-IUS grows to include women at higher risk for STIs. This study assessed the impact of the LNG-IUS on development of Chlamydia trachomatis pelvic inflammatory disease, using a baboon model.

Methods

Baboons with and those without the LNG-IUS were cervically inoculated with C. trachomatis and monitored daily, and cervical and fallopian tube swab specimens were collected weekly for C. trachomatis quantitation by nucleic acid amplification testing and culture. Vaginal swab specimens were collected for cytokine analysis, and serum samples were obtained for detection of C. trachomatis antibodies.

Results

The LNG-IUS resulted in an increased C. trachomatis burden in the cervix, with the bacterial burden in the LNG-IUS group diverging from that in the non-LNG-IUS group by 6 weeks after infection. One of 7 baboons in the non-LNG-IUS group and 2 of 6 in the LNG-IUS group developed pelvic inflammatory disease, while 3 animals in each group met criteria suggestive of pelvic inflammatory disease. LNG-IUS increased baseline interleukin 8 levels but failed to further upregulate interleukin 8 during infection. In LNG-IUS recipients, early perturbations in the interleukin 1β axis corresponded to decreased C. trachomatis clearance and increased T-helper type 2 immune responses.

Conclusion

LNG-IUS use results in delayed clearance of C. trachomatis and might alter the reproductive tract immune environment.

Levonorgestrel intrauterine system for endometrial protection

Progestogen is added to estrogen in hormone replacement therapy solely to provide endometrial protection, so it is logical to deliver it to its site of action. The levonorgestrel intrauterine system, which delivers 20 mug levonorgestrel per day, is now licensed for use as the progestogen component of continuous combined hormone replacement therapy. No cases of endometrial hyperplasia or carcinoma, and no significant increase in endometrial thickness, have been reported in clinical trials. The bleeding profile is similar to that obtained with other types of continuous combined hormone replacement therapy. The levonorgestrel intrauterine system thus provides a potentially bleed-free alternative to sequential therapy for perimenopausal women.

Canadian Contraception Consensus (Part 3 of 4): Chapter 7--Intrauterine Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, ease of use, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the relative cost and availability of cited contraceptive methods in Canada.

EVIDENCE

Published literature was retrieved through searches of Medline and The Cochrane Database from January 1994 to January 2015 using appropriate controlled vocabulary (e.g., contraception, sexuality, sexual health) and key words (e.g., contraception, family planning, hormonal contraception, emergency contraception). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English from January 1994 to January 2015. Searches were updated on a regular basis in incorporated in the guideline to June 2015. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of the evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). CHAPTER 7: INTRAUTERINE CONTRACEPTION:

SUMMARY STATEMENTS

1. Intrauterine contraceptives are as effective as permanent contraception methods. (II-2) 2. The use of levonorgestrel-releasing intrauterine system (LNG-IUS) 52 mg by patients taking tamoxifen is not associated with recurrence of breast cancer. (I) 3. Intrauterine contraceptives have a number of noncontraceptive benefits. The levonorgestrel-releasing intrauterine system (LNG-IUS) 52 mg significantly decreases menstrual blood loss (I) and dysmenorrhea. (II-2) Both the copper intrauterine device and the LNG-IUS significantly decrease the risk of endometrial cancer. (II-2) 4. The risk of uterine perforation decreases with inserter experience but is higher in postpartum and breastfeeding women. (II-2) 5. The risk of pelvic inflammatory disease (PID) is increased slightly in the first month after intrauterine contraceptive (IUC) insertion, but the absolute risk is low. Exposure to sexually transmitted infections and not the IUC itself is responsible for PID occurring after the first month of use. (II-2) 6. Nulliparity is not associated with an increased risk of intrauterine contraceptive expulsion. (II-2) 7. Ectopic pregnancy with an intrauterine contraceptive (IUC) is rare, but when a pregnancy occurs with an IUC in situ, it is an ectopic pregnancy in 15% to 50% of the cases. (II-2) 8. In women who conceive with an intrauterine contraceptive (IUC) in place, early IUC removal improves outcomes but does not entirely eliminate risks. (II-2) 9. Intrauterine contraceptives do not increase the risk of infertility. (II-2) 10. Immediate insertion of an intrauterine contraceptive (10 minutes postplacental to 48 hours) postpartum or post-Caesarean section is associated with a higher continuation rate compared with insertion at 6 weeks postpartum. (I) 11. Immediate insertion of an intrauterine contraceptive (IUC; 10 minutes postplacental to 48 hours) postpartum or post-Caesarean section is associated with a higher risk of expulsion. (I) The benefit of inserting an IUC immediately postpartum or post-Caesarean section outweighs the disadvantages of increased risk of perforation and expulsion. (II-C) 12. Insertion of an intrauterine contraceptive in breastfeeding women is associated with a higher risk of uterine perforation in the first postpartum year. (II-2) 13. Immediate insertion of an intrauterine contraceptive (IUC) post-abortion significantly reduces the risk of repeat abortion (II-2) and increases IUC continuation rates at 6 months. (I) 14. Antibiotic prophylaxis for intrauterine contraceptive insertion does not significantly reduce postinsertion pelvic infection. (I) RECOMMENDATIONS: 1. Health care professionals should be careful not to restrict access to intrauterine contraceptives (IUC) owing to theoretical or unproven risks. (III-A) Health care professionals should offer IUCs as a first-line method of contraception to both nulliparous and multiparous women. (II-2A) 2. In women seeking intrauterine contraception (IUC) and presenting with heavy menstrual bleeding and/or dysmenorrhea, health care professionals should consider the use of the levonorgestrel intrauterine system 52 mg over other IUCs. (I-A) 3. Patients with breast cancer taking tamoxifen may consider a levonorgestrel-releasing intrauterine system 52 mg after consultation with their oncologist. (I-A) 4. Women requesting a levonorgestrel-releasing intrauterine system or a copper-intrauterine device should be counseled regarding changes in bleeding patterns, sexually transmitted infection risk, and duration of use. (III-A) 5. A health care professional should be reasonably certain that the woman is not pregnant prior to inserting an intrauterine contraceptive at any time during the menstrual cycle. (III-A) 6. Health care providers should consider inserting an intrauterine contraceptive immediately after an induced abortion rather than waiting for an interval insertion. (I-B) 7. In women who conceive with an intrauterine contraceptive (IUC) in place, the diagnosis of ectopic pregnancy should be excluded as arly as possible. (II-2A) Once an ectopic pregnancy has been excluded, the IUC should be removed without an invasive procedure. The IUC may be removed at the time of a surgical termination. (II-2B) 8. In the case of pelvic inflammatory disease, it is not necessary to remove the intrauterine contraceptive unless there is no clinical improvement after 48 to 72 hours of appropriate antibiotic treatment. (II-2B) 9. Routine antibiotic prophylaxis for intrauterine contraceptive (IUC) insertion is not indicated. (I-B) Health care providers should perform sexually transmitted infection (STI) testing in women at high risk of STI at the time of IUC insertion. If the test is positive for chlamydia and/or gonorrhea, the woman should be appropriately treated postinsertion and the IUC can remain in situ. (II-2B) 10. Unscheduled bleeding in intrauterine contraception users, when persistent or associated with pelvic pain, should be investigated to rule out infection, pregnancy, gynecological pathology, expulsion or malposition. (III-A)

Intrauterine devices and endometrial cancer risk: a pooled analysis of the Epidemiology of Endometrial Cancer Consortium

Intrauterine devices (IUDs), long-acting and reversible contraceptives, induce a number of immunological and biochemical changes in the uterine environment that could affect endometrial cancer (EC) risk. We addressed this relationship through a pooled analysis of data collected in the Epidemiology of Endometrial Cancer Consortium. We combined individual-level data from 4 cohort and 14 case-control studies, in total 8,801 EC cases and 15,357 controls. Using multivariable logistic regression, we estimated pooled odds ratios (pooled-ORs) and 95% confidence intervals (CIs) for EC risk associated with ever use, type of device, ages at first and last use, duration of use and time since last use, stratified by study and adjusted for confounders. Ever use of IUDs was inversely related to EC risk (pooled-OR = 0.81, 95% CI = 0.74-0.90). Compared with never use, reduced risk of EC was observed for inert IUDs (pooled-OR = 0.69, 95% CI = 0.58-0.82), older age at first use (≥ 35 years pooled-OR = 0.53, 95% CI = 0.43-0.67), older age at last use (≥ 45 years pooled-OR = 0.60, 95% CI = 0.50-0.72), longer duration of use (≥ 10 years pooled-OR = 0.61, 95% CI = 0.52-0.71) and recent use (within 1 year of study entry pooled-OR = 0.39, 95% CI = 0.30-0.49). Future studies are needed to assess the respective roles of detection biases and biologic effects related to foreign body responses in the endometrium, heavier bleeding (and increased clearance of carcinogenic cells) and localized hormonal changes.

Effects of the levonorgestrel-releasing intrauterine system on cell proliferation, Fas expression and steroid receptors in endometriosis lesions and normal endometrium

BACKGROUND

The objectives of this study were: (i) to evaluate the effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) on both proliferation and apoptosis markers and hormone receptors of the eutopic and ectopic endometrium of women experiencing pain related to endometriosis and (ii) to compare the results with those obtained with GnRH agonist (GnRHa) injections.

METHODS

Pre- and post-treatment endometrium and endometriosis specimens were obtained from 22 women experiencing pain related to endometriosis who were treated with LNG-IUS (n = 11) or GnRHa (n = 11) for 6 months. Changes in the expression of proliferating cell nuclear antigen, Fas, progesterone receptor (PRA) and estrogen receptor alpha (ER-alpha) were analyzed by immunohistochemistry.

RESULTS

The cell proliferation index was significantly reduced in the epithelium and stroma of both the eutopic and the ectopic endometrium after treatment with the LNG-IUS and GnRHa. Only LNG-IUS users showed an increased H-score for Fas in the epithelium of the eutopic and ectopic endometrium (P < 0.05). Expression of ER-alpha and PRA by the glandular epithelium was lower in the eutopic endometrium after both treatments, but this reduction was noted in the ectopic endometrium only after LNG-IUS treatments (P < 0.05). No difference was detected between groups for any of the markers.

CONCLUSIONS

LNG-IUS reduced both cell proliferation and the expression of PRA and ER-alpha and increased Fas expression in the eutopic and ectopic endometrium of patients with endometriosis. Some of these actions were not observed with GnRHa.

Differential elevation of matrix metalloproteinase expression in women exposed to levonorgestrel-releasing intrauterine system for a short or prolonged period of time

BACKGROUND

The levonorgestrel-releasing intrauterine system (LNG-IUS) is an effective contraceptive and has many non-contraceptive health benefits. However, it is commonly associated with irregular endometrial bleeding. Metalloproteinases contribute to extracellular matrix (ECM) remodelling and regulate bleeding during the menstrual cycle. Enhanced metalloproteinase expression participates in the pathogenesis of breakthrough bleeding. Thus the objective of this study was to compare matrix metalloproteinase (MMP) expression in endometrium during luteal phase and in short-term (1 month) and long-term (> or =6 months) LNG-IUS users.

METHODS

MMP expression was analysed by semi-quantitative RT-PCR and immunohistochemistry. Gelatinase activity was determined by gelatin zymography.

RESULTS

MMP-1, -2, -3, -7, -9 and -12 mRNAs levels were increased, whereas that of MMP-26 was decreased in the endometrium of LNG-IUS users. MMP-1, -2, -3, -7 and -9 were localized by immunohistochemistry in all biopsies in the short-term group but in only 0-27% in the control group. The incidence of positive immunostaining for MMP-2 and -3 decreased significantly in the long-term compared with short-term LNG-IUS users. MMP-26 was localized in all biopsies from the control group but in only 14 and 25% from the short- and long-term LNG-IUS groups, respectively. In both LNG groups, the numbers of macrophages (the major source of MMP-12) was increased.

CONCLUSIONS

MMP-1, active MMP-2, MMP-3, MMP-7, MMP-9 and MMP-12 are more prevalent in the short-term LNG-IUS group, suggesting their important contribution to ECM breakdown and transient bleeding. The decrease in the percentage of women expressing MMP-2 and -3 might contribute to the decreased occurrence of unwanted spotting and bleeding in long-term LNG-IUS users.

Mifepristone alters expression of endometrial steroid receptors and their cofactors in new users of medroxyprogesterone acetate

OBJECTIVE

To evaluate the effect of mifepristone on the expression of endometrial steroid receptors and their co-factors in depot medroxyprogesterone acetate (DMPA) users.

DESIGN

A prospective, randomized, placebo-controlled trial.

SETTING

Reproductive research center.

PATIENT(S)

Fifty healthy women with regular menstrual cycle.

INTERVENTION(S)

One hundred fifty milligrams of DMPA were given every 3 months. Two pills (25 mg each) of placebo or mifepristone were administered every 14 days during the DMPA therapy. Four endometrial biopsy specimens were obtained from each patient.

MAIN OUTCOME MEASURE(S)

The expression of estrogen receptor subtypes alpha and beta (ERalpha and ERbeta), progesterone receptors A and B (PRAB and PRB), and androgen receptor messenger RNA and protein was detected by real-time polymerase chain reaction and immunohistochemistry, respectively. Steroid receptor coactivator 1 (SRC-1), silencing mediator for retinoid and thyroid-hormone receptors, and cell proliferation were evaluated by immunohistochemistry.

RESULT(S)

The expression of endometrial ERalpha, PRAB, PRB, and SRC-1 was increased significantly after 1 week of mifepristone, but the increase was no longer seen after 10 weeks. A positive correlation between endometrial ERalpha, PRAB, PRB, and SRC-1 production and proliferation was demonstrated.

CONCLUSION(S)

Short-term exposure of mifepristone in new starters of DMPA increases the expression of endometrial ERalpha, PRAB, PRB, and SRC-1 and promotes cell proliferation. Prolonged exposure to mifepristone does not alter the suppression of these receptors that are caused by DMPA and continues to result in endometrial atrophy.

Effects of mifepristone on proliferation and apoptosis of human endometrium in new users of medroxyprogesterone acetate

BACKGROUND

Mifepristone has been demonstrated to decrease breakthrough bleeding (BTB) in users of progestin-only contraceptives.

METHODS

Endometrial biopsies were collected from 50 normal cycling women who were new users of depot medroxyprogesterone acetate (DMPA) randomized to receive either mifepristone or placebo before, during and after treatment. Proliferation, apoptosis and sex steroid receptors were evaluated by either immunohistochemistry or TUNEL assay.

RESULTS

Administration of mifepristone to DMPA-exposed endometrium for 1 week significantly increased endometrial expression of Ki-67 (MKI67), estrogen receptor (ER)alpha and progesterone receptors A and B (PRAB) and decreased the number of TUNEL-positive and caspase-3 (CASP3)-active cells in the endometrial stroma. However, after 10 weeks of mifepristone treatment, no significant difference in proliferation, apoptosis and the expression of ERalpha or PRAB could be detected between the endometrium treated with DMPA alone and endometrium treated with mifepristone and DMPA.

CONCLUSIONS

Administration of mifepristone to DMPA users significantly increases endometrial proliferation and decreases endometrial stromal apoptosis in the short term. Prolonged exposure to mifepristone does not counteract the inhibitory effects of progestin therapy on endometrial proliferation. Estrogen and progesterone receptors may play an important role in these effects.

Effect of mifepristone on proliferation and apoptosis of Ishikawa endometrial adenocarcinoma cells

OBJECTIVE

To determine the mechanism by which mifepristone improves breakthrough bleeding, the effects of mifepristone on proliferation and apoptosis of Ishikawa endometrial carcinoma cells were evaluated in the presence and absence of progestin.

DESIGN

Prospective basic research study.

SETTING

Research laboratories for reproductive health at a university medical school.

PATIENT(S)

None.

INTERVENTION(S)

Ishikawa cells were cultured in vitro. Mifepristone and/or medroxyprogesterone acetate at various concentrations were added to the cells.

MAIN OUTCOME MEASURE(S)

Determination of cell proliferation and apoptosis.

RESULT(S)

Colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and bromodeoxyuridine (BrdU) labeling analysis demonstrated that mifepristone inhibited the growth of Ishikawa cells and percentage of BrdU-labeled cells in a time- and dose-dependent manner. Flow cytometry analysis demonstrated that mifepristone at 100 micromol/L, which completely inhibited cell proliferation, increased the proportion of cells in the S phase and diminished the cells in the G2/M phase. Apoptosis was identified by annexin-V-fluorescein isothiocyanate binding and caspase-3 activation. Immunofluorescent double labeling of Ishikawa cells in the absence or presence of mifepristone revealed that BAX protein expression increased and translocated from cytosol to mitochondria.

CONCLUSION(S)

Mifepristone inhibited cell growth by arresting cell cycle progression at S phase, induced apoptosis through caspase-3 activation, and modulated apoptosis regulatory genes BCL2/BAX and FAS/FASLG in Ishikawa cells. Together, these data imply that the improvement in breakthrough bleeding observed with mifepristone might be due to diminished volume of endometrial tissue similar to that seen with endometrial atrophy.

Expression of vascular endothelial growth factors and their receptors in human endometrium from women experiencing abnormal bleeding patterns after prolonged use of a levonorgestrel-releasing intrauterine system

BACKGROUND

Menstrual bleeding disturbances are a common initial complaint among users of the levonorgestrel-releasing intrauterine system (LNG-IUS). In this study, women who experienced bleeding disturbances recurring after a previous period of problem-free use and who therefore wanted removal of their LNG-IUD were investigated. Vascular endothelial growth factors (VEGFs) and their receptors are thought to be involved in normal endometrial angiogenesis. The aim of the study was to elucidate the possible association of these VEGF and receptors with bleeding disturbances among users of LNG-IUS.

METHODS

Endometrial biopsies were obtained from users of the LNG-IUS who complained of bleeding disturbances (n = 17) and from women without such problems (n = 14). The endometrial expression of these VEGFs and their receptors was analysed using immunohistochemistry.

RESULTS

Endometrial endothelial cells from LNG-IUS users with menstrual bleeding disturbances exhibited significantly higher immunoreactivity for VEGFR-1 and VEGFR-3 than those from women without bleeding disturbances. Stromal cells showed significantly lower immunoreactivity for VEGF-A in samples from LNG-IUS users with bleeding disturbances than in those without.

CONCLUSION

Changes in the expression of these angiogenic growth factors and their receptors in LNG-IUS-exposed endometrium might be involved in the formation of fragile and dysfunctional blood vessels that subsequently give rise to bleeding disturbances.

Mechanisms of action of intrauterine devices: update and estimation of postfertilization effects

There are many potential mechanisms of action for the intrauterine device (IUD), which vary by type of IUD (inert, copper, or hormonal). This paper reviews the evidence for each potential mechanism of action. On the basis of available data for fertilization rates and clinical pregnancy rates, the relative contribution of mechanisms acting before or after fertilization were quantitatively estimated. These estimates indicate that, although prefertilization effects are more prominent for the copper IUD, both prefertilization and postfertilization mechanisms of action contribute significantly to the effectiveness of all types of intrauterine devices.

Effects of the levonorgestrel-releasing intrauterine system on proliferation and apoptosis in the endometrium

BACKGROUND

The levonorgestrel-releasing intrauterine system (LNg-IUS) has been shown to be effective in the management of menorrhagia. In order to evaluate the effects of LNg-IUS on endometrial proliferation and apoptosis, proliferating cell nuclear antigen (PCNA) expression, apoptosis, Fas and Bcl-2 protein expression in the endometrium were determined at the early proliferative phase of the menstrual cycle before and 3 months after LNg-IUS insertion.

METHODS

PCNA, Fas and Bcl-2 protein expression were analysed using an avidin-biotin immunoperoxidase method. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end labelling (TUNEL) method.

RESULTS

PCNA, immunolocalized both in the nuclei of endometrial glands and stroma was less abundant 3 months after insertion (P < 0.05). Bcl-2 protein, immunolocalized in the cytoplasm of endometrial glands but not in the stroma, became scanty 3 months after insertion. Fas antigen, immunolocalized only in endometrial glands before insertion, became prominent in both endometrial glands and stroma 3 months after insertion. The apoptosis-positive rate of the nuclei in both endometrial glands and stroma was significantly higher 3 months after insertion relative to that before insertion (P < 0.05).

CONCLUSIONS

LNg-IUS resulted in a decrease in endometrial proliferation and an increase in apoptosis in endometrial glands and stroma. The increase in apoptosis associated with increased Fas antigen expression and decreased Bcl-2 protein expression in the endometrium may be one of the underlying molecular mechanisms by which LNg-IUS insertion causes the atrophic change of the endometrium.