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Folliculogenesis Is Not Fully Inhibited during GnRH Analogues Treatment in Mice Challenging Their Efficiency to Preserve the Ovarian Reserve during Chemotherapy in This Model.

Horicks F, Van Den Steen G, Houben S, Englert Y, Demeestere I - PLoS ONE (2015)

Bottom Line: Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im).Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist.GnRHa had no effect on Cy-induced follicular damages.

View Article: PubMed Central - PubMed

Affiliation: Research Laboratory on Human Reproduction, Université Libre de Bruxelles (ULB), Brussels, Belgium.

ABSTRACT
As many chemotherapy regimens induce follicular depletion, fertility preservation became a major concern in young cancer patients. By maintaining follicles at the resting stage, gonadotropin-releasing hormone analogues (GnRHa) were proposed as an ovarian-protective option during chemotherapy. However, their efficacy and mechanisms of action remain to be elucidated. Mice were dosed with cyclophosphamide (Cy, 100-500 mg/kg i.p) to quantify follicular depletion and evaluate apoptosis at different times. We observed a dose-dependent depletion of the follicular reserve within 24 hours after Cy injection with a mean follicular loss of 45% at the dose of 200mg/kg. Apoptosis occurs in the granulosa cells of growing follicles within 12 hours after Cy treatment, while no apoptosis was detected in resting follicles suggesting that chemotherapy acutely affects both resting and growing follicles through different mechanisms. We further tested the ability of both GnRH agonist and antagonist to inhibit oestrus cycles, follicular growth and FSH secretion in mice and to protect ovarian reserve against chemotherapy. Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im). Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist. GnRHa had no effect on Cy-induced follicular damages. Thus, we showed that GnRHa were not as efficient at inhibiting the pituitary-gonadal axis in mice as in human. Furthermore, the acute depletion of primordial follicles observed after chemotherapy does not support the hypothesis that the ovary may be protected by gonadotropin suppression.

No MeSH data available.


Related in: MedlinePlus

Dose- and time-related follicular depletion induced by chemotherapy.The follicular population was evaluated by counting all the follicles in every fifth section of each whole serial sectioned ovary from mice treated with (a) 100, 200, or 500 mg/kg of Cy and sacrificed after 7 days or (b) 200 mg/kg of Cy and sacrificed after 1 or 7 days. Results are expressed as mean ± SD; *p < 0.05 compared with controls. (c) Representative immunohistological sections showing apoptotic follicles (stained by TUNEL and CASPASE-3) in 200mg/kg Cy-treated mice sacrificed at different time points. TUNEL staining peaked at 12–18 hours, whereas CASPASE-3 peaked at 8–12 hours. Scale bar = 100 μm.
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pone.0137164.g001: Dose- and time-related follicular depletion induced by chemotherapy.The follicular population was evaluated by counting all the follicles in every fifth section of each whole serial sectioned ovary from mice treated with (a) 100, 200, or 500 mg/kg of Cy and sacrificed after 7 days or (b) 200 mg/kg of Cy and sacrificed after 1 or 7 days. Results are expressed as mean ± SD; *p < 0.05 compared with controls. (c) Representative immunohistological sections showing apoptotic follicles (stained by TUNEL and CASPASE-3) in 200mg/kg Cy-treated mice sacrificed at different time points. TUNEL staining peaked at 12–18 hours, whereas CASPASE-3 peaked at 8–12 hours. Scale bar = 100 μm.

Mentions: Mice were treated with different doses of Cy (100, 200, 500 mg/kg) or saline solution and sacrificed 7 days after injection. As expected, Cy induced a dose-dependent follicular depletion (Fig 1A). All follicular stages were affected, but the depletion was mainly observed in the primordial follicular pool. The total follicular loss reached 28.40% (p = 0.247), 45.19% (p < 0.01), and 73.45% (p < 0.001) for Cy doses of 100, 200, and 500 mg/kg, respectively, compared with the control (Table 1). Resting follicle population loss reached 51.91% (p = 0.01) with 200 mg/kg Cy, while only 18.59% of growing follicles were destroyed compared with the control. We observed an increase in the proportion of growing follicles compared with the resting population, as the proportion of growing follicles reached 23.21%, 31.40%, and 49.16% for chemotherapy doses of 100, 200, and 500mg/kg, respectively, compared with 20.68% for the control (Table 1).


Folliculogenesis Is Not Fully Inhibited during GnRH Analogues Treatment in Mice Challenging Their Efficiency to Preserve the Ovarian Reserve during Chemotherapy in This Model.

Horicks F, Van Den Steen G, Houben S, Englert Y, Demeestere I - PLoS ONE (2015)

Dose- and time-related follicular depletion induced by chemotherapy.The follicular population was evaluated by counting all the follicles in every fifth section of each whole serial sectioned ovary from mice treated with (a) 100, 200, or 500 mg/kg of Cy and sacrificed after 7 days or (b) 200 mg/kg of Cy and sacrificed after 1 or 7 days. Results are expressed as mean ± SD; *p < 0.05 compared with controls. (c) Representative immunohistological sections showing apoptotic follicles (stained by TUNEL and CASPASE-3) in 200mg/kg Cy-treated mice sacrificed at different time points. TUNEL staining peaked at 12–18 hours, whereas CASPASE-3 peaked at 8–12 hours. Scale bar = 100 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4556658&req=5

pone.0137164.g001: Dose- and time-related follicular depletion induced by chemotherapy.The follicular population was evaluated by counting all the follicles in every fifth section of each whole serial sectioned ovary from mice treated with (a) 100, 200, or 500 mg/kg of Cy and sacrificed after 7 days or (b) 200 mg/kg of Cy and sacrificed after 1 or 7 days. Results are expressed as mean ± SD; *p < 0.05 compared with controls. (c) Representative immunohistological sections showing apoptotic follicles (stained by TUNEL and CASPASE-3) in 200mg/kg Cy-treated mice sacrificed at different time points. TUNEL staining peaked at 12–18 hours, whereas CASPASE-3 peaked at 8–12 hours. Scale bar = 100 μm.
Mentions: Mice were treated with different doses of Cy (100, 200, 500 mg/kg) or saline solution and sacrificed 7 days after injection. As expected, Cy induced a dose-dependent follicular depletion (Fig 1A). All follicular stages were affected, but the depletion was mainly observed in the primordial follicular pool. The total follicular loss reached 28.40% (p = 0.247), 45.19% (p < 0.01), and 73.45% (p < 0.001) for Cy doses of 100, 200, and 500 mg/kg, respectively, compared with the control (Table 1). Resting follicle population loss reached 51.91% (p = 0.01) with 200 mg/kg Cy, while only 18.59% of growing follicles were destroyed compared with the control. We observed an increase in the proportion of growing follicles compared with the resting population, as the proportion of growing follicles reached 23.21%, 31.40%, and 49.16% for chemotherapy doses of 100, 200, and 500mg/kg, respectively, compared with 20.68% for the control (Table 1).

Bottom Line: Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im).Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist.GnRHa had no effect on Cy-induced follicular damages.

View Article: PubMed Central - PubMed

Affiliation: Research Laboratory on Human Reproduction, Université Libre de Bruxelles (ULB), Brussels, Belgium.

ABSTRACT
As many chemotherapy regimens induce follicular depletion, fertility preservation became a major concern in young cancer patients. By maintaining follicles at the resting stage, gonadotropin-releasing hormone analogues (GnRHa) were proposed as an ovarian-protective option during chemotherapy. However, their efficacy and mechanisms of action remain to be elucidated. Mice were dosed with cyclophosphamide (Cy, 100-500 mg/kg i.p) to quantify follicular depletion and evaluate apoptosis at different times. We observed a dose-dependent depletion of the follicular reserve within 24 hours after Cy injection with a mean follicular loss of 45% at the dose of 200mg/kg. Apoptosis occurs in the granulosa cells of growing follicles within 12 hours after Cy treatment, while no apoptosis was detected in resting follicles suggesting that chemotherapy acutely affects both resting and growing follicles through different mechanisms. We further tested the ability of both GnRH agonist and antagonist to inhibit oestrus cycles, follicular growth and FSH secretion in mice and to protect ovarian reserve against chemotherapy. Although GnRHa were efficient to disrupt oestrus cycles, they failed to inhibit follicular development, irrespective of the doses and injection sites (sc or im). Around 20% of healthy growing follicles were still observed during GnRHa treatment and serum FSH levels were not reduced either by antagonist or agonist. GnRHa had no effect on Cy-induced follicular damages. Thus, we showed that GnRHa were not as efficient at inhibiting the pituitary-gonadal axis in mice as in human. Furthermore, the acute depletion of primordial follicles observed after chemotherapy does not support the hypothesis that the ovary may be protected by gonadotropin suppression.

No MeSH data available.


Related in: MedlinePlus