Apoptotic Follicle Research Articles

Visualization of Apoptotic Ovarian Follicles during Aedes aegypti Mosquito Egg Maturation by Fluorescent Imaging Studies.

In insects, oocyte resorption (oosorption) or follicular atresia is one of the key physiological processes and evolutionary strategies used to optimize reproductive fitness. Mosquitoes are ideal model organisms for studying egg maturation in arthropods, as their follicle development is initiated only following the ingestion of a blood meal, followed by a carefully orchestrated series of hormonally regulated events leading to egg maturation. A cohort of approximately 100 follicles per mosquito ovary begin developing synchronously. However, a significant fraction of follicles ultimately undergo apoptosis and oosorption, especially when available resources from the blood meal are limited. Therefore, simple, rapid, and reliable techniques to accurately evaluate follicular atresia are necessary to understand mechanisms underlying follicle development in insects. This protocol describes how to detect apoptotic follicle cells within the Aedes aegypti mosquito ovaries using a commercially available fluorescent-labeled inhibitor of caspases (FLICA). Caspases are key players in animal apoptosis. In this assay, the FLICA reagent enters the intracellular compartment of follicles in dissected mosquito ovaries and covalently binds to active caspases. The bound reagent remains within the cell and its fluorescent signal can be observed by confocal microscopy. Although this method was specifically developed for visualizing apoptotic ovarian follicles during Ae. aegypti mosquito egg development, it should be applicable to other mosquito tissues that undergo caspase-mediated program cell death in a time-dependent manner.

Follicle outcomes in human ovarian tissue: effect of freezing, culture, and grafting

To study the effect of freezing, invitro culture (IVC) and grafting to chorioallantoic membrane (CAM) on follicle outcomes in human ovarian tissue. An experimental study. University-based research laboratory. Fresh and cryopreserved ovarian tissue from 10 patients was donated to research with their consent and institutional review board approval. Fresh and frozen-thawed ovarian cortical pieces were in vitro-cultured and compared (fresh-IVC vs FT-IVC). The FT-IVC fragments were then examined against fragments grafted to CAM (FT-CAM). After both IVC and CAM grafting, ovarian cortical pieces (4×2×1 mm3) were analyzed on days 0, 1, and6. Follicle analyses included histology (count and classification) and immunohistochemistry (Ki67 [proliferation], caspase-3 [apoptosis], 1A and 1B light chain 3B [autophagy], p-Akt, FOXO1, and p-rpS6 [PI3K activation]). Droplet digital polymerase chain reaction further explored expression of PI3K pathway- and oocyte-related genes in tissue sections. No major differences were detected between fresh-IVC and FT-IVC tissues in any conducted analyses. Although a significant drop was observed in primordial follicle (PF) proportions in the fresh-IVC and FT-IVC groups (d0 vs. d6, P<.002), they held steady in the FT-CAM group (d0 vs. d6, P>.05). The PF rates were also significantly higher in the FT-CAM group than the FT-IVC group on d6 (P=.02). Importantly, avian erythrocytes were already present in 30% of implants from d1. Apoptotic and autophagic follicle rates increased during IVC (P<.008), but remained significantly lower in the FT-CAM group (P<.01), confirming superior follicle preservation in CAM-grafted tissue. Upregulation of the PI3K/FOXO pathway was established in the IVC groups, demonstrating PF activation, whereas significant pathway downregulation was detected in the FT-CAM group (P<.03). The droplet digital polymerase chain reaction tests confirmed oocyte growth during IVC and follicle autophagy in all groups; however, the PI3K pathway appeared to be differentially modulated in tissues and follicles. Invitro culture induces PF depletion with no additional impact of freezing. Grafting to CAM preserves the PF pool by curbing follicle activation, apoptosis, and autophagy, probably thanks to rapid graft revascularization and/or the circulating embryonic antimüllerian hormone. These findings highlight the importance of enhancing neoangiogenesis in ovarian grafts and investigating the potential benefits of administering antimüllerian hormone to prevent PF burnout.

P-437 Follicle activation in human ovarian tissue: impact of freezing, culture and grafting

Abstract Study question How does freezing, in vitro culture (IVC) and grafting to chorioallantoic membrane (CAM) affect follicle activation through the PI3K pathway in human ovarian tissue? Summary answer Freezing does not trigger further follicle activation. Although IVC and CAM do induce follicle activation, the process is significantly curbed in the CAM group. What is known already While massive follicle activation has been shown to occur through the PI3K pathway in frozen-thawed human ovarian tissue after both short-term xenotransplantation and IVC, it remains poorly understood in fresh ovarian tissue, raising many questions about the effect of freezing on follicle activation. Furthermore, grafting ovarian tissue to CAM has been found to limit follicle activation in animal ovarian tissue, though its impact on human follicles is yet to be elucidated. Study design, size, duration Thirty fresh cortical fragments from 5 patients and 50 frozen-thawed tissue pieces from another 5 patients were investigated. We first compared fresh fragments (fresh-IVC) with frozen-thawed tissue (FT-IVC) by IVC. These cultured frozen-thawed fragments were then examined against frozen-thawed fragments grafted to CAM (FT-CAM). After both IVC and CAM grafting, ovarian cortical pieces (4x2x1 mm) were analyzed on day (D) 0, 1 and 6. Participants/materials, setting, methods Follicle analyses included histology (count and classification), transmission electron microscopy (ultrastructure), immunohistochemistry (Ki67 for follicle proliferation, c-caspase-3 for follicle apoptosis, LC3B for follicle autophagy, p-AKT for PI3K activation and p-rpS6 for PI3K/mTOR activation), and immunofluorescence (FOXO1 for PI3K/FOXO activation). Subcellular localization of FOXO1 was determined in primordial follicles on high-resolution images using structured illumination microscopy. Droplet digital PCR further investigated expression of PI3K pathway-related genes (TSC1 and CDKN1B) and oocyte growth-related genes (GDF9 and LHX8). Main results and the role of chance No differences were detected between the fresh-IVC and the FT-IVC groups in any conducted analyses. After both IVC and CAM grafting, a significant decrease was observed in primordial follicle proportions in all groups on D6 vs D0 (p &amp;lt; 0.01), associated with a substantial increase in intermediate follicle proportions (p &amp;lt; 0.05). In the FT-CAM group, however, the percentage of primordial follicles stabilized between D1 and D6, showing significantly higher rates than the FT-IVC group on D6 (p = 0.04) and reflecting better preservation of the primordial follicle pool in the FT-CAM group. While apoptotic follicle rates increased in all conditions (D0 vs D6, p &amp;lt; 0.03), they remained significantly lower in the FT-CAM group than in the FT-IVC group on D6 (p = 0.01), confirming superior follicle preservation in CAM-grafted tissue. In primordial follicles, significantly lower levels of p-rpS6 were noted over time in all conditions (D0 vs D6, p &amp;lt; 0.009), but there was a significant shift in FOXO1 to a nuclear localization in the FT-CAM group compared to the FT-IVC group on D1 (p = 0.03), indicating inhibition of follicle activation. Limitations, reasons for caution As demonstrated by our results, the CAM model appears to be effective at preserving the follicle pool. However, our study did not investigate the underlying mechanisms behind this improved follicle preservation after thawing. Wider implications of the findings Our data confirm that the freezing procedure itself does not cause follicle burnout. Moreover, the CAM model looks to be capable of preserving the follicle pool, hypothetically thanks to rapid revascularization and circulating embryonic anti-Müllerian hormone. Trial registration number Not applicable

Antifreeze Protein Supplementation During the Warming of Vitrified Bovine Ovarian Tissue Can Improve the Ovarian Tissue Quality After Xenotransplantation.

The occurrence of ice crystallization during ovarian tissue (OT) cryopreservation causes unavoidable cryodamage, and ice recrystallization during the warming is more detrimental than ice crystallization. Here, we investigated that antifreeze protein (AFP) treatment during the warming procedure can improve the bovine OT quality after xenotransplantation (XT). Bovine OTs (n=120) were evenly assigned to four groups: fresh, vitrified-warmed, vitrified-warmed with 10 mg/mL Leucosporidium ice-binding protein (LeIBP, a type of AFP) (LeIBP-10), and vitrified-warmed with 20 mg/mL LeIBP (LeiBP-20). LeIBPs were added to the first warming solution. Twenty pieces of OTs were assigned to each category. The remaining 10 OTs from each category were assigned to the XT-Fresh control, XT-Vitrified-warmed control, XT-LeIBP-10, and XT-LeIBP-20 groups, respectively, and xenotransplanted to 9-week-old ovariectomized nude mice for one week. LeIBP treatment during the warming step increased morphological follicle normality and decreased apoptotic follicle ratios after vitrification-warming and XT. The XT-vitrified-warmed control group showed significantly reduced microvessel density and increased fibrosis when compared to that of the XT-fresh group. Microvessel density and fibrosis were recovered in both LeIBP treated groups. There was no significant difference between the LeIBP-10 and LeIBP-20 groups in all outcomes. AFP treatment during the warming procedure can prevent OT damage, and improve ovarian follicle morphology and apoptosis in both the vitrified-warmed bovine OT and its graft. After confirmation in a human study, AFPs can potentially be applied to human OT cryopreservation to reduce cryodamage and improve the OT quality.

Effect of treatment with angiopoietin-2 and vascular endothelial growth factor on the quality of xenografted bovine ovarian tissue in mice.

Cryopreservation and transplantation of ovarian tissue (OT) represents a method for fertility preservation. However, as the transplantation is performed without vessel anastomosis, unavoidable ischemic damage occurs. To reduce this ischemic damage and improve outcomes after transplantation, we used two kind of angiogenic factors, angiopoietin-2 (ang-2) and vascular endothelial growth factor (VEGF). Fresh or vitrified-warmed bovine OTs were prepared for xenotransplantation (XT). Fresh OTs were immediately xenografted into nude mice (XT-Fresh). Vitrified-warmed OTs were xenografted into four subgroups of mice, which were injected intraperitoneally before XT with saline (XT-Vitri), Ang-2 (XT-Ang-2), VEGF (XT-VEGF), and a combination of Ang-2 and VEGF (XT-Combined). Seven or 28 days post-grafting, grafted OTs and blood samples were collected for evaluation. Follicle normality was higher in the angiogenic factor-treated groups than in the XT-Vitri group. The XT-VEGF and the XT-Combined showed higher (P<0.05) follicular density than the XT-Vitri group. The highest apoptotic follicle ratio was observed in the XT-Vitri group on day 7; this was decreased (P<0.05) in the XT-Combined group. Microvessel densities were higher in the angiogenic factor-treated groups than in the XT-Vitri group. The largest fibrotic area was showed in the XT-Vitri group on day 28, and it was decreased (P<0.05) in the XT-combined group. Based on these results, administration of Ang-2 and VEGF to recipients prior to XT appeared to alleviate ischemic damage by enhancing angiogenesis, which resulted in the maintenance of follicle integrity and density, and reduced follicle apoptosis and OT fibrosis.

Improvement in Ovarian Tissue Quality with Supplementation of Antifreeze Protein during Warming of Vitrified Mouse Ovarian Tissue.

Ice easily recrystallizes during warming after vitrification, and antifreeze protein (AFP) can inhibit the re-crystallization. However, no study has evaluated the effect of AFP treatment only thereon during warming. This study sought to compare AFP treatment protocols: a conventional protocol with AFP treatment during vitrification and first-step warming and a new protocol with AFP treatment during the first-step warming only. According to the protocols, 10 mg/mL of LeIBP (a type of AFP) was used. Five-week-old B6D2F1 mouse ovaries were randomly divided into a vitrified-warmed control and two experimental groups, one treated with the conventional AFP treatment protocol (LeIBP-all) and the other with the new AFP treatment protocol (LeIBP-w). For evaluation, ratios of ovarian follicle integrity, apoptosis, and DNA double-strand (DDS) damage/repairing were analyzed. The LeIBP-treated groups showed significantly higher intact follicle ratios than the control, and the results were similar between the LeIBP-treated groups. Apoptotic follicle ratios were significantly lower in both LeIBP-treated groups than the control, and the results were not significantly different between the LeIBP-treated groups. With regard to DDS damage/repairing follicle ratio, significantly lower ratios were recorded in both LeIBP-treated groups, compared to the control, and the results were similar between the LeIBP-treated groups. This study demonstrated that both protocols with LeIBP had a beneficial effect on maintaining follicle integrity and preventing follicle apoptosis and DDS damage. Moreover, the new protocol showed similar results to the conventional protocol. This new protocol could optimize the mouse ovary vitrification-warming procedure using AFP, while minimizing the treatment steps.

A combination of simvastatin and methylprednisolone improves the quality of vitrified-warmed ovarian tissue after auto-transplantation.

Does the preoperative administration of simvastatin and methylprednisolone enhance mouse ovarian quality after auto-transplantation of vitrified-warmed ovarian tissue (OT)? Treatment with combined simvastatin and methylprednisolone enhances the quality of transplanted mouse OTs. The prevention of ischemic injury after transplantation of OT is critical for preserving the ovarian follicles. Preoperative administration of simvastatin (a cholesterol-lowering drug) has beneficial effects on various organ transplantations. Moreover, donor treatment with simvastatin and methylprednisolone (main effects are on immune response) prevents ischemia-reperfusion injury and has a beneficial effect on allograft survival in rat cardiac allografts. A total of 232 6-week-old B6D2F1 mice were randomly distributed into fresh control, vitrified-warmed control and experimental groups (n = 10-17 per group). The experimental groups were as follows: sham control, simvastatin, methylprednisolone and co-treatment groups. In the experimental groups, the mice were administered simvastatin (5 mg/kg, orally), methylprednisolone (15 mg/kg, i.v.) or a combination of simvastatin and methylprednisolone 2 h before ovariectomy, whereas the sham control mice received normal saline. Whole ovaries were removed from the mice and vitrified by two-step vitrification procedures. The vitrified ovaries were warmed 1 week later and auto-transplanted under the bilateral kidney capsules. The ovaries and blood samples were collected 2, 7 and 21 days (D) after transplantation for histological analysis, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, immunohistochemistry for CD31 and serum anti-Mullerian hormone (AMH) level estimation. Embryonic development was evaluated after IVF of oocytes obtained from the transplanted ovary. The group that received simvastatin and methylprednisolone showed a significantly improved intact (Grade 1) follicle ratio (D2: P < 0.001, D7: P < 0.05 and D21: P < 0.001), apoptotic follicle ratio (D21: P < 0.05), CD31-positive area (D7: P < 0.05 and D21: P < 0.05) and serum AMH level (D7: P < 0.001) after transplantation when compared with the sham control. However, no difference was noted in the fertilization and blastocyst formation rates, number of total and apoptotic blastomeres per blastocyst and inner cell mass/trophectoderm ratio among the four transplantation groups. Although we evaluated the beneficial effects of simvastatin and methylprednisolone in the present study, we did not unravel the corresponding protective mechanisms. Our results suggest that a combination of simvastatin and methylprednisolone has beneficial effects on the quality and functioning of transplanted OT. This combined treatment can potentially be applied clinically to humans and domestic animals subject to further studies.

Optimal vitrification protocol for mouse ovarian tissue cryopreservation: effect of cryoprotective agents and in vitro culture on vitrified-warmed ovarian tissue survival

What is the optimal vitrification protocol according to the cryoprotective agent (CPA) for ovarian tissue (OT) cryopreservation? The two-step protocol with 7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO) for 10 min then 20% EG, 20% DMSO and 0.5 M sucrose for 5 min showed the best results in mouse OT vitrification. Establishing the optimal cryopreservation protocol is one of the most important steps to improve OT survival. However, only a few studies have compared vitrification protocols with different CPAs and investigated the effect of in vitro culture (IVC) on vitrified-warmed OT survival. Some recent papers proposed that a combination of CPAs has less toxicity than one type of CPA. However, the efficacy of different types and concentrations of CPA are not yet well documented. A total of 644 ovaries were collected from 4-week-old BDF1 mice, of which 571 ovaries were randomly assigned to 8 groups and vitrified using different protocols according to CPA composition and the remaining 73 ovaries were used as controls. After warming, each of the eight groups of ovaries was further randomly divided into four subgroups and in vitro cultured for 0, 0.5, 2 and 4 h, respectively. Ovaries of the best two groups among the eight groups were autotransplanted after IVC. The CPA solutions for the eight groups were composed of EDS, ES, ED, EPS, EF, EFS, E and EP, respectively (E, EG; D, DMSO; P, propanediol; S, sucrose; F, Ficoll). The IVC medium was composed of α-minimal essential medium, 10% fetal bovine serum and 10 mIU/ml follicle-stimulating hormone (FSH). Autotransplantation of vitrified-warmed OTs after IVC (0 to 4 h) using the EDS or ES protocol was performed, and the grafts were recovered after 3 weeks. Ovarian follicles were assessed for morphology, apoptosis, proliferation and FSH level. The percentages of the morphologically intact (G1) and apoptotic follicles in each group at 0, 0.5, 2 and 4 h of IVC were compared. For G1 follicles at 0 and 4 h of IVC, the EDS group showed the best results at 63.8 and 46.6%, respectively, whereas the EP group showed the worst results at 42.2 and 12.8%, respectively. The apoptotic follicle ratio was lowest in the EDS group at 0 h (8.1%) and 0.5 h (12.7%) of IVC. All of the eight groups showed significant decreases in G1 follicles and increases in apoptotic follicles as IVC duration progressed. After autotransplantation, the EDS 0 h group showed a significantly higher G1 percentage (84.9%) than did the other groups (42.4-58.8%), while only the ES 4 h group showed a significant decrease in the number of proliferative cells (80.6%, 87.6-92.9%). However, no significant differences in apoptotic rates and FSH levels were observed between the groups after autotransplantation. The limitation of this study was the absence of in vitro fertilization using oocytes obtained from OT grafts, which should be performed to confirm the outcomes of ovarian cryopreservation and transplantation. We compared eight vitrification protocols according to CPA composition and found the EDS protocol to be the optimal method among them. The data presented herein will help improve OT cryopreservation protocols for humans or other animals.

Sphingosine-1-phosphate prevents chemotherapy-induced human primordial follicle death

Can Sphingosine-1-phosphate (S1P), a ceramide-induced death pathway inhibitor, prevent cyclophosphamide (Cy) or doxorubicin (Doxo) induced apoptotic follicle death in human ovarian xenografts? S1P can block human apoptotic follicle death induced by both drugs, which have differing mechanisms of cytotoxicity. S1P has been shown to decrease the impact of chemotherapy and radiation on germinal vesicle oocytes in animal studies but no human translational data exist. Experimental human ovarian xenografting to test the in vivo protective effect of S1P on primordial follicle survival in the chemotherapy setting. The data were validated by assessing the same protective effect in the ovaries of xenografted mice in parallel. Xenografted mice were treated with Cy (75 mg/kg), Cy+S1P (200 μM), Doxo (10 mg/kg), Doxo+S1P or vehicle only (Control). S1P was administered via continuous infusion using a mini-osmotic pump beginning 24 h prior to and ending 72 h post-chemotherapy. Grafts were then recovered and stained with anti-caspase 3 antibody for the detection of apoptosis in primordial follicles. The percentage of apoptotic to total primordial follicles was calculated in each group. Both Cy and Doxo resulted in a significant increase in apoptotic follicle death in human ovarian xenografts compared with controls (62.0 ± 3.9% versus 25.7 ± 7.4%, P < 0.01 and 76.7 ± 7.4% versus 25.7 ± 7.4%, P < 0.01, respectively). This chemotherapy-induced apoptotic death was reduced both in the Cy+S1P (32.7 ± 4.4%, P < 0.01) and the Doxo+S1P group (27.1 ± 7.6%, P < 0.01) compared with Cy and Doxo groups, respectively. In the Doxo+S1P and Cy+S1P groups, the percentages of apoptotic follicles were similar to those of vehicle-treated controls (P > 0.05). The findings from the ovaries of the severe combined immunodeficient mice mirrored the findings with human tissue. The functionality of the rescued human ovarian follicles needs to be evaluated in future studies though the studies in rodents showed that rescued oocytes can result in healthy offspring. In addition, the impact of S1P on cancer cells should be further studied. S1P and its future analogs hold promise for preserving fertility by pharmacological means for patients undergoing chemotherapy. This research is supported by NIH's NICHD and NCI (5R01HD053112-06 and 5R21HD061259-02) and the Flemish Foundation for Scientific Research (FWO-Vlaanderen, grant number FWO G0.065.11N10). The authors have no conflicts of interest to disclose.

Sphingosine-1-phosphate prevents human primordial follicle death induced by a diverse set of chemotherapy agents

Chemotherapy agents such as cyclophosphamide (Cy) and doxorubicin (D) act through diverse mechanisms of action. We have previously shown that both agents result in apoptotic death of human primordial follicles. Sphingosine-1-Phosphate (S1P) is a ceramide-induced death pathway inhibitor. Our aim was to elucidate whether S1P can prevent Cy or D-induced apoptotic follicle death in human ovarian xenografts.

Prevention of chemotherapy-induced damage to ovarian reserve by sphingosine-1-phosphate

1097 Background: Chemotherapy agents such as cyclophosphamide (Cy) and doxorubicin (D) are known to compromise ovarian function. We have previously shown that these agents alter ovarian function by causing apoptotic death of primordial follicles and thereby causing diminishment of ovarian reserve (Cancer Research 2007; Aging 2011). While assisted reproduction techniques exist to preserve fertility there has been no proven approach to pharmacologic preservation of ovarian function. Sphingosine-1-Phosphate (S1P) is a naturally occurring ceramide-induced death pathway inhibitor. Here we investigated whether S1P can prevent Cy or D-induced apoptotic follicle death in mouse ovaries. Methods: Eight wk old NOD mice (n=23) were treated with Cy (75 mg/kg), Cy+S1P (200 μM), D (10 mg/kg), D+S1P or vehicle only (Control). S1P was administered via continuous infusion using a mini-osmotic pump beginning 3 hours prior to single dose chemotherapy injection for 72 hours. Ovaries were removed 72h later and serially sectioned, and stained with anti-caspase 3 (AC-3) antibody for the detection of apoptosis in primordial follicles. The ratio of apoptotic to total follicles was expressed as percentage in each group. Results: Both Cy and D resulted in significant increase in apoptotic follicle death compared to controls (48.2±11.6 vs. 28.2±8.9, p=0.016 and 46.4±5.4 vs. 24.8±5.2, p=0.004, respectively). Percentages of apoptotic follicles were similar between Cy and D-treated groups (48.2±11.6 vs. 46.4±5.4, P=NS) indicating that these agents were equally gonadotoxic. S1P treatment resulted in a significant decrease in the percentage of apoptotic follicles both in the Cy (25.6±3.5, P&lt;0.011) and the D group (32.2±10.8, P&lt; 0.013) compared to controls. In the S1P-treated groups, the percentages of apoptotic follicles were similar to those in untreated controls indicating that S1P completely blocked Cy and D-induced apoptotic follicle death. Conclusions: S1P can block apoptotic follicle death induced by highly cytotoxics agents. In addition, we showed that S1P can block follicle death by chemotherapy agents that act through different molecular mechanisms. If targeted delivery systems can be developed, S1P may hold significant promise in preserving fertility by pharmacological means.

Apoptosis of rat's ovarian follicle cells induced by triptolide in vivo.

This present study aimed to investigate ovarian follicular apoptosis and development in rats administrated with different dosages of triptolide (TR).Thirty healthy female Sprague Dawley rats were randomly divided into 3 groups (n = 10), including placebo group (water and 0.06% Dimethyl Sulfoxide); high dose(HD) group (120 μg/kg.d TR) and low dose (LD) group (60 μg/kg.d TR). Vaginal smear was daily performed to estimate each rat’s estrous cycle, while body weight was measured every 4 days to evaluate rat’s growth pattern and adjust the dosage. Left ovary of each rat was resected and then serial section was performed for follicular classification and counts. Apoptosis was detected with TUNEL assay and then positively-stained follicles were classified and calculated. Compared with the placebo and LD groups, the average estrous cycle was significantly longer in the HD group (p < 0.01). The secondary follicle in both HD and LD groups was significantly more than the control groups (p < 0.05), while there were no significant changes of primordial follicle and antral follicle among three groups. Furthermore, higher proportion of apoptotic follicle in the stage of secondary follicle was found in both HD and LD groups. TR presented dose-dependent inhibition on estrous cycle and apoptosis induction in secondary follicle, which might account for female gonad depression activities. Key words: Triptolide; ovarian follicle; apoptosis; rat.

A novel molecular mechanism for anticancer drug-induced ovarian failure: Irinotecan HCl, an anticancer topoisomerase I inhibitor, induces specific FasL expression in granulosa cells of large ovarian follicles to enhance follicular apoptosis

Clinical use of CPT-11 combination chemotherapy frequently induces ovarian dysfunction in premenopausal and perimenopausal cancer patients, but its mechanism remains unclear. Mouse experiments were performed to clarify the molecular mechanism of CPT-11-induced ovarian dysfunction. Clinically therapeutic doses of CPT-11 were injected intraperitoneally into 8-week-old female MCH mice, and their ovaries were examined by the TUNEL assay to detect dead cells. Immunohistochemical examinations were simultaneously performed to detect the expression of activated caspase 3, Fas antigen and Fas ligand (FasL). Furthermore, normal murine ovarian tissue fragments were incubated with recombinant soluble FasL in organ cultures and stained by the TUNEL assay to detect apoptotic cells. Intraperitoneal CPT-11 injections induced specific TUNEL-positive cells and cell death with cleaved caspase 3 expression among large ovarian follicular granulosa cells. Apoptotic follicles (follicles containing >/=10 TUNEL-positive cells per ovarian section) were only found among large follicles. The final apoptotic follicle ratios were approximately 30% of the total follicles independent of the CPT-11 dose, while CPT-11 dose-dependently enhanced apoptotic processes in murine ovarian follicles. Fas antigen was expressed in most ovarian cells, with extremely high expression levels detected in luteal cells. CPT-11 injections did not significantly increase the Fas expression levels in ovarian cells. Although no FasL expression was detected in normal ovarian tissues, CPT-11 injections significantly induced specific FasL expression in granulosa cells. Incubation of organ-cultured normal murine ovarian tissue fragments with recombinant mouse soluble FasL significantly increased the numbers of TUNEL-positive granulosa and luteal cells. In conclusion, CPT-11 dose-dependently induced specific FasL expression in granulosa cells of developing ovarian follicles. The induced FasL reacted with the Fas antigen constitutively expressed on granulosa cells, such that apoptosis can only be enhanced and induced in granulosa cells in an autocrine and/or paracrine manner. This cell lineage-specific and differentiation stage-specific apoptosis in granulosa cells is thought to be the main molecular mechanism of the ovarian dysfunction induced by CPT-11 combination chemotherapy.

Hair Cycle Control by Estrogens: Catagen Induction via Estrogen Receptor (ER)-α Is Checked by ERβ Signaling

Although 17beta-estradiol (E2) is recognized as a potent hair growth modulator, our knowledge of estrogen function, signaling, and target genes in hair biology is still very limited. Between the two recognized estrogen receptors (ERs), ER alpha and ER beta, only ER alpha had been detected in murine skin. Here we show that ER alpha, ER beta, and ER beta ins are all expressed throughout the murine hair cycle, both at the protein and RNA level, but show distinct expression patterns. We confirm that topical E2 arrests murine pelage hair follicles in telogen and demonstrate that E2 is a potent inducer of premature catagen development. The ER antagonist ICI 182.780 does not induce anagen prematurely but accelerates anagen development and wave spreading in female mice. ER beta knockout mice display accelerated catagen development along with an increase in the number of apoptotic hair follicle keratinocytes. This suggests that, contrary to previous concepts, ER beta does indeed play a significant role in murine hair growth control: whereas the catagen-promoting properties of E2 are mediated via ER alpha, ER beta mainly may function as a silencer of ER alpha action in hair biology. These findings illustrate the complexity of hair growth modulation by estrogens and suggest that one key to more effective hair growth manipulation with ER ligands lies in the use of selective ER alpha or -beta antagonists/agonists. Our study also underscores that the hair cycling response to estrogens offers an ideal model for studying the controls and dynamics of wave propagation in biological systems.

Detection of apoptosis in the ovarian follicle cells of ecdyonurus venosus (ephemeroptera, heptageniidae)

Programmed cell death, or apoptosis, occurs in ovarian follicle cells of Ecdyonurus venosus (Ephemeroptera, Heptageniidae) nymphs in the developmental phase characterized by pale wing‐pads. Follicle cells are responsible for egg vitelline and chorionic envelope synthesis. Apoptosis was detected in these cells both on the basis of their ultrastructural morphological characteristics and immunocytochemically by the TUNEL reaction, which proves nuclear DNA fragmentation. Cells showed structural changes after the synthesis of chorionic knob‐terminated coiled threads (KCTs), which typically perform an adhesive function in these insects. The morphological characteristics of apoptosis were evident under transmission electron microscopy after the completion of choriogenesis and consisted in: a) the lobated nucleus; b) chromatin forming small clumps close to the nuclear envelope; c) vacuoles increasing in size in the cell cytoplasm, which was filled with rough endoplasmic reticulum. Apoptotic follicle cells were particularly evident at one egg pole, thus reflecting the polar concentration of these cells in order to synthesize the KCTs. At the end stage of oogenesis in this insect group, as in many other multicellular organisms, apoptosis appears to be a common fate for cells that have fulfilled their role.

Dynamics of apoptosis in the ovarian follicle cells during the late stages of Drosophila oogenesis.

In the present study, we demonstrate the apoptotic events of the ovarian follicle cells during the late stages of oogenesis in Drosophila melanogaster. Follicle cell morphology appears normal from stage 10 up to stage 14, exhibiting a euchromatic nucleus and a well-organized cytoplasm. First signs of apoptosis appear at the anterior pole of the egg chamber at stage 14A. They are characterized by loss of microvilli at the apical cell membrane, alterations in nuclear morphology, such as chromatin condensation and convolution of the nuclear membrane, and also by condensation and vacuolization of the cytoplasm. During the following stage 14B, the follicle cell nuclei contain fragmented DNA as is demonstrated by acridine orange staining and TUNEL (TdT-mediated dUTP nick end-labeling) assay. Finally, the apoptotic follicle cells seem to detach from the eggshell when the mature egg chamber exits the ovariole. The detached follicle cells exhibit condensed nuclear chromatin, a disorganized cytoplasm with crowded organelles and are surrounded by epithelial cells. The above results seem to be associated with the abundant phagocytosis that we observed at the entry of the lateral oviducts, where the epithelial cells contain apoptotic cell bodies. Additionally, we tested the effect of etoposide treatment in the follicular epithelium and found that it induces apoptosis in a stage- and site-specific manner. These observations suggest a possible method of absorption of the apoptotic follicle cells that prevents the blockage of the ovarioles and helps the regular production of mature eggs.

Patterns of Proliferation and Apoptosis during Murine Hair Follicle Morphogenesis

In this study, we have correlated cutaneous apoptosis and proliferation in neonatal mice during hair follicle morphogenesis. We have applied a novel triple- staining technique that uses Ki67 immunoreactivity as a marker of proliferation as well as TUNEL and Hoechst 33342 staining as apoptosis markers. We have also assessed the immunoreactivity of interleukin-1 beta-converting enzyme, caspase 1, a key enzyme in the execution of apoptosis, and of P-cadherin, which has been suggested as a key adhesion receptor in segregating proliferating keratinocytes. The TUNEL data were systematically compared with high resolution light microscopy and transmission electron microscopy data. Virtually all keratinocytes of the developing hair bud were strongly Ki67(+), suggesting that the hair bud is not an epidermal invagination but primarily the product of localized keratinocyte proliferation. As hair follicle development advanced, three distinct foci of proliferation became apparent: the distal outer root sheath around the hair canal, the mid outer root sheath, and the proximal hair matrix. Of these proliferating hair follicle keratinocytes only defined subsets expressed P-cadherin. TUNEL(+) cells in the hair follicle were not found before stage 5 of murine hair follicle morphogenesis. During the early stages of hair follicle development, interleukin-1 beta-converting enzyme immunoreactivity was present on all keratinocytes, but virtually disappeared from the proximal hair follicle epithelium later on. High resolution light microscopy/transmission electron microscopy revealed scattered and clustered apoptotic keratinocytes in all epithelial hair follicle compartments throughout hair follicle development, including its earliest stages. This highlights striking differences in the demarcation of apoptotic hair follicle keratinocytes between the TUNEL technique and high resolution light microscopy/transmission electron microscopy and suggests a role for apoptosis in sculpting the hair follicle even during early hair follicle development.