Short photoperiod-induced ovarian regression is mediated by apoptosis in Siberian hamsters (Phodopus sungorus)

Moffatt-Blue, Chantelle; Sury, Jonathan; Young, Kelly A.

doi:10.1530/rep.1.00870

Cited by 41 publications

(87 citation statements)

References 53 publications

(46 reference statements)

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“…Plasma LH was elevated in FORKO mice relative to wild type and plasma estradiol was undetectable Balla et al (2003). Conversely, serum LH concentration has been reported to be much lower in SD than in LD female hamsters (Dodge & Badura 2002), but E 2 concentration does not appear to be consistently lower in SD when compared with LD hamsters (van den Hurk et al 2002, Scotti et al 2007; but see Moffatt-Blue et al 2006). The similarities and differences in the ovarian phenotype of SD hamsters with that of GDF9 deficient and FORKO mice should help direct future investigations to determine the mechanisms/signals that underlie the luteinization of granulosa cells and the up-regulation of AMH in SD ovaries.…”

Section: Discussionmentioning

confidence: 99%

Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus

Kabithe

Place²

2008

Reproduction

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Fertility and fecundity decline with advancing age in female mammals, but reproductive aging was decelerated in Siberian hamsters (Phodopus sungorus) raised in a short-day (SD) photoperiod. Litter success was significantly improved in older hamsters when reared in SD and the number of primordial follicles was twice that of females held in long days (LD). Because anti-Mü llerian hormone (AMH) appears to inhibit the recruitment of primordial follicles in mice, we sought to determine whether the expression patterns of AMH differ in the ovaries and serum of hamsters raised in SD versus LD. Ovaries of SD female hamsters are characterized by a paucity of follicular development beyond the secondary stage and are endowed with an abundance of large eosinophilic cells, which may derive from granulosa cells of oocyte-depleted follicles. In ovaries from 10-week-old SD hamsters, we found that the so-called 'hypertrophied granulosa cells' were immunoreactive for AMH, as were granulosa cells within healthy-appearing primary and secondary follicles. Conversely, ovaries from age-matched LD animals lack the highly eosinophilic cells present in SD ovaries. Therefore, AMH staining in LD was limited to primary and secondary follicles that are comparable in number to those found in SD ovaries. The substantially greater AMH expression in SD ovaries probably reflects the abundance of hypertrophied granulosa cells in SD ovaries and their relative absence in LD ovaries. The modulation of ovarian AMH by day length is a strong mechanistic candidate for the preservation of primordial follicles in female hamsters raised in a SD photoperiod. Reproduction (2008) 135 335-342

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Section: Discussionmentioning

confidence: 99%

Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus

Kabithe

Place²

2008

Reproduction

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“…Fiftytwo female hamsters were then randomly assigned to a short day room (8L:16D), while the remainder (n=18) stayed in LD conditions as controls. In order to ensure complete reproductive regression with SD exposure, animals remained housed in these photoperiods for 14 weeks (Moffatt-Blue et al, 2006;Ross et al, 2005). Short day females were randomly assigned to one of five groups: post-transfer (PT) week 0, 1, 2, 4, or 8 (n=10−11 per group).…”

Section: Animalsmentioning

confidence: 99%

“…LD female control hamsters were randomly assigned into 3 groups and tissue was collected at the same time as PT week 0, 2, and 8 as a baseline comparison (n=6 per group). Four male hamsters were placed among the female hamsters in each room to promote ovarian cyclicity, and estrous cycles were synchronized by placing soiled male bedding in to the female cages four days prior to tissue collection (Dodge et al, 2002), as we have done before (Moffatt-Blue et al, 2006). Body mass was measured, and the stage of the estrous cycle was determined by vaginal cytology on collection dates.…”

Section: Animalsmentioning

confidence: 99%

“…In the laboratory, exposure to 12 weeks of short (<12.5 hrs of light per day) photoperiod induces ovarian atrophy, or regression, resulting in reduced or absent ovulation and decreased plasma estradiol concentrations (Moffatt-Blue et al, 2006;Schlatt et al, 1993). In contrast, maintenance of LD breeding rodents in chronic (18−30 weeks) SD, or transferring animals from 12−14 weeks of SD to stimulatory LD conditions (>12.5 hrs of light per day) induces gonadal recrudescence (Schlatt et al, 1993;Ross et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…Given that ovarian recrudescence involves the return of organ function, MMPs are likely to play a key role in restoring ovarian performance. Because ovarian regression in Siberian hamsters is characterized by a reduction in follicle numbers, a decline in gonadal mass, and an absence of corpora lutea (Moffatt-Blue et al, 2006), recrudescence of non-functional ovarian tissue would likely show reciprocal changes during the return of ovarian function. We hypothesized that ovarian recrudescence would occur rapidly with LD stimulation of reproductively regressed females, and that return of function would be characterized by an increased number of tertiary follicles and corpora lutea as well as a subsequent increase in serum estradiol.…”

Section: Introductionmentioning

confidence: 99%

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Differential expression of matrix metalloproteinases during stimulated ovarian recrudescence in Siberian hamsters (Phodopus sungorus)

Salverson

McMichael

Sury

et al. 2008

General and Comparative Endocrinology

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The matrix metalloproteinases (MMPs) are a family of extracellular matrix-cleaving enzymes involved in ovarian remodeling. In many non-tropical species, including Siberian hamsters, ovarian remodeling is necessary for the functional changes associated with seasonal reproduction. We evaluated MMPs and their endogenous inhibitors (TIMPs), during photoperiod-induced ovarian recrudescence in Siberian hamsters. Hamsters were transferred from long-day (LD;16:8) to shortday (SD;8:16) photoperiods for 14wks, and then returned to LD for 0,1,2,4, or 8wks for collection of ovaries and plasma. Post-transfer (PT) LD exposure increased body and ovarian mass. Numbers of corpora lutea and antral, but not preantral follicles increased in PT groups. Plasma estradiol concentrations were lower in PT wks0−4, and returned to LD levels at PTwk8. No change was observed in relative MMP/TIMP mRNA levels at PTwk0 (SDwk14) as compared to LD. Photostimulation increased MMP-2 mRNA at PTwk8 as compared to PT wks 0−1. MMP-14 mRNA expression peaked at PTwks1−2 as compared to LD levels, while MMP-13 expression was low during this time. TIMP-1 mRNA peaked at PT wk8 as compared to PTwks0−4. No changes were noted in MMP-9 and TIMP-2 mRNA expression. In general, MMP/TIMP protein immunodetection followed the same patterns with most staining occurring in granulosa cells of follicles and corpora lutea. Our data suggest that mRNA and protein for several members of the MMP/TIMP families are expressed in Siberian hamster ovaries during recrudescence. Because of the variation observed in expression patterns, MMPs and TIMPs may be differentially involved with photo-stimulated return to ovarian function.

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Rapid changes in ovarian mRNA induced by brief photostimulation in Siberian hamsters (Phodopus sungorus)

2015

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This study sought to characterize the rapid intraovarian mRNA response of key folliculogenic factors that may contribute to the restoration of folliculogenesis during 2-10 days of photostimulation in Siberian hamsters. Adult hamsters were exposed to short photoperiod (8L:16D) for 14 weeks (SD). A subset were then transferred to long photoperiod (16L:8D) for 2(PT day-2), 4(PT day-4), or 10 days (PT day-10). Quantitative real-time PCR was used to measure intraovarian mRNA expression of: gonadotropin releasing hormone (GnRH), follicle stimulating hormone β-subunit (FSHβ-subunit), luteinizing hormone β-subunit (LHβ-subunit), FSH and LH receptors, estrogen receptorsα and β (Esr1 and Esr2), matrix metalloproteinase (MMP)-2 and -9, anti-Müllerian hormone (AMH), inhibin-α subunit, fibroblast growth factor-2 (FGF-2) and proliferating cell nuclear antigen (PCNA). Compared to SD, plasma FSH concentrations increased on PT day-4 and the number of antral follicles and corpora lutea increased on PT day-10. FSHR and inhibin-α mRNA expression also increased on PT day-4, whereas LHR and proliferation marker PCNA both increased on PT day-10 as compared to SD. Esr1 mRNA increased on PT day-2 and remained significantly increased as compared to SD, whereas Esr1 mRNA increased only on PT day-2, similar to FGF-2 and MMP-2 results. No differences were observed in mRNA expression in ovarian GnRH, FSHβ- and LHβ-subunits, AMH, and MMP-9 mRNA with 2-10 days of photostimulation. Rapid increases in intraovarian FSHR and inhibin-α mRNA and antral follicle/corpora lutea numbers suggest that the ovary is primed to react quickly to the FSH released in response to brief periods of photostimulation.

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Short photoperiod-induced ovarian regression is mediated by apoptosis in Siberian hamsters (Phodopus sungorus)

Cited by 41 publications

References 53 publications

Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus

Photoperiod-dependent modulation of anti-Müllerian hormone in female Siberian hamsters, Phodopus sungorus

Differential expression of matrix metalloproteinases during stimulated ovarian recrudescence in Siberian hamsters (Phodopus sungorus)

Rapid changes in ovarian mRNA induced by brief photostimulation in Siberian hamsters (Phodopus sungorus)

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