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Ovarian matrix metalloproteinases are differentially regulated during the estrous cycle but not during short photoperiod induced regression in Siberian hamsters (Phodopus sungorus).

Vrooman LA, Young KA - Reprod. Biol. Endocrinol. (2010)

Bottom Line: MMP-9 exhibited a 1.6-1.8 fold decrease in mRNA expression in DII (p<0.05), while all other MMPs and TIMPs tested showed no significant difference in mRNA expression in the estrous cycle.Extent of immunostaining for MMP-14, TIMP-1, and TIMP-2 was significantly more abundant in P, E, and DI than in DII (p<0.05).No significant changes were observed in MMP and TIMP mRNA or extent of protein immunostaining with exposure to 3, 6, 9, or 12 weeks of SD, however protein was present and was localized to follicular and luteal steroidogenic cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Reproductive Biology Group, Department of Biological Sciences, California State University, Long Beach, Long Beach, CA 90840, USA.

ABSTRACT

Background: Matrix metalloproteinases (MMPs) are implicated as mediators for ovarian remodeling events, and are involved with ovarian recrudescence during seasonal breeding cycles in Siberian hamsters. However, involvement of these proteases as the photoinhibited ovary undergoes atrophy and regression had not been assessed. We hypothesized that 1) MMPs and their tissue inhibitors, the TIMPs would be present and differentially regulated during the normal estrous cycle in Siberian hamsters, and that 2) MMP/TIMP mRNA and protein levels would increase as inhibitory photoperiod induced ovarian degeneration.

Methods: MMP-2, -9, -14 and TIMP-1 and -2 mRNA and protein were examined in the stages of estrous (proestrus [P], estrus [E], diestrus I [DI], and diestrus II [DII]) in Siberian hamsters, as well as after exposure to 3, 6, 9, and 12 weeks of inhibitory short photoperiod (SD).

Results: MMP-9 exhibited a 1.6-1.8 fold decrease in mRNA expression in DII (p<0.05), while all other MMPs and TIMPs tested showed no significant difference in mRNA expression in the estrous cycle. Extent of immunostaining for MMP-2 and -9 peaked in P and E then significantly declined in DI and DII (p<0.05). Extent of immunostaining for MMP-14, TIMP-1, and TIMP-2 was significantly more abundant in P, E, and DI than in DII (p<0.05). Localization of the MMPs and TIMPs had subtle differences, but immunostaining was predominant in granulosa and theca cells, with significant differences noted in staining intensity between preantral follicles, antral follicles, corpora lutea, and stroma classifications. No significant changes were observed in MMP and TIMP mRNA or extent of protein immunostaining with exposure to 3, 6, 9, or 12 weeks of SD, however protein was present and was localized to follicular and luteal steroidogenic cells.

Conclusions: Although MMPs appear to be involved in the normal ovarian estrus cycle at the protein level in hamsters, those examined in the present study are unlikely to be key players in the slow atrophy of tissue as seen in Siberian hamster ovarian regression.

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Extent of immunostaining for MMPs and TIMPs during the estrous cycle. Bar graphs represent mean ± SEM immunostaining index levels (scores of 0-4) for (A) MMP-2, (B) MMP-9, (C) MMP-14, (D) TIMP-1, and (E) TIMP-2. Index indicates overall extent dark red stained cells across the ovarian cross section in the different stages of estrous in Siberian hamsters. Groups with different letters are significantly different (p < 0.05).
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Figure 5: Extent of immunostaining for MMPs and TIMPs during the estrous cycle. Bar graphs represent mean ± SEM immunostaining index levels (scores of 0-4) for (A) MMP-2, (B) MMP-9, (C) MMP-14, (D) TIMP-1, and (E) TIMP-2. Index indicates overall extent dark red stained cells across the ovarian cross section in the different stages of estrous in Siberian hamsters. Groups with different letters are significantly different (p < 0.05).

Mentions: The overall extent of protein expression was similar among all MMPs and TIMPs, exhibiting higher protein expression in P and E, and lower protein expression in DII (Figure 5). Total extent of ovarian immunostaining observed for MMP-2 peaked in P and E then declined in DI (p < 0.05) and again in DII (p < 0.01; Figure 5A). Extent of MMP-9 staining across the ovarian cross sections peaked in P and E, then declined 1.2-fold in DI (p < 0.01), and 3.4-fold in DII (p < 0.001; Figure 5B). Extent of MMP-14 staining was abundant in P, E, and DI then declined 3-fold in DII (p < 0.001; Figure 5C). Extent of immunostaining for TIMP-1 was significantly more abundant in P, E, and DI than in DII, declining 3-fold in DII (p < 0.001; Figure 5D). Extent of TIMP-2 staining across the ovarian cross sections peaked in P, E, and DI and declined in diestrus II (p < 0.01; Figure 5E).


Ovarian matrix metalloproteinases are differentially regulated during the estrous cycle but not during short photoperiod induced regression in Siberian hamsters (Phodopus sungorus).

Vrooman LA, Young KA - Reprod. Biol. Endocrinol. (2010)

Extent of immunostaining for MMPs and TIMPs during the estrous cycle. Bar graphs represent mean ± SEM immunostaining index levels (scores of 0-4) for (A) MMP-2, (B) MMP-9, (C) MMP-14, (D) TIMP-1, and (E) TIMP-2. Index indicates overall extent dark red stained cells across the ovarian cross section in the different stages of estrous in Siberian hamsters. Groups with different letters are significantly different (p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2913988&req=5

Figure 5: Extent of immunostaining for MMPs and TIMPs during the estrous cycle. Bar graphs represent mean ± SEM immunostaining index levels (scores of 0-4) for (A) MMP-2, (B) MMP-9, (C) MMP-14, (D) TIMP-1, and (E) TIMP-2. Index indicates overall extent dark red stained cells across the ovarian cross section in the different stages of estrous in Siberian hamsters. Groups with different letters are significantly different (p < 0.05).
Mentions: The overall extent of protein expression was similar among all MMPs and TIMPs, exhibiting higher protein expression in P and E, and lower protein expression in DII (Figure 5). Total extent of ovarian immunostaining observed for MMP-2 peaked in P and E then declined in DI (p < 0.05) and again in DII (p < 0.01; Figure 5A). Extent of MMP-9 staining across the ovarian cross sections peaked in P and E, then declined 1.2-fold in DI (p < 0.01), and 3.4-fold in DII (p < 0.001; Figure 5B). Extent of MMP-14 staining was abundant in P, E, and DI then declined 3-fold in DII (p < 0.001; Figure 5C). Extent of immunostaining for TIMP-1 was significantly more abundant in P, E, and DI than in DII, declining 3-fold in DII (p < 0.001; Figure 5D). Extent of TIMP-2 staining across the ovarian cross sections peaked in P, E, and DI and declined in diestrus II (p < 0.01; Figure 5E).

Bottom Line: MMP-9 exhibited a 1.6-1.8 fold decrease in mRNA expression in DII (p<0.05), while all other MMPs and TIMPs tested showed no significant difference in mRNA expression in the estrous cycle.Extent of immunostaining for MMP-14, TIMP-1, and TIMP-2 was significantly more abundant in P, E, and DI than in DII (p<0.05).No significant changes were observed in MMP and TIMP mRNA or extent of protein immunostaining with exposure to 3, 6, 9, or 12 weeks of SD, however protein was present and was localized to follicular and luteal steroidogenic cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Reproductive Biology Group, Department of Biological Sciences, California State University, Long Beach, Long Beach, CA 90840, USA.

ABSTRACT

Background: Matrix metalloproteinases (MMPs) are implicated as mediators for ovarian remodeling events, and are involved with ovarian recrudescence during seasonal breeding cycles in Siberian hamsters. However, involvement of these proteases as the photoinhibited ovary undergoes atrophy and regression had not been assessed. We hypothesized that 1) MMPs and their tissue inhibitors, the TIMPs would be present and differentially regulated during the normal estrous cycle in Siberian hamsters, and that 2) MMP/TIMP mRNA and protein levels would increase as inhibitory photoperiod induced ovarian degeneration.

Methods: MMP-2, -9, -14 and TIMP-1 and -2 mRNA and protein were examined in the stages of estrous (proestrus [P], estrus [E], diestrus I [DI], and diestrus II [DII]) in Siberian hamsters, as well as after exposure to 3, 6, 9, and 12 weeks of inhibitory short photoperiod (SD).

Results: MMP-9 exhibited a 1.6-1.8 fold decrease in mRNA expression in DII (p<0.05), while all other MMPs and TIMPs tested showed no significant difference in mRNA expression in the estrous cycle. Extent of immunostaining for MMP-2 and -9 peaked in P and E then significantly declined in DI and DII (p<0.05). Extent of immunostaining for MMP-14, TIMP-1, and TIMP-2 was significantly more abundant in P, E, and DI than in DII (p<0.05). Localization of the MMPs and TIMPs had subtle differences, but immunostaining was predominant in granulosa and theca cells, with significant differences noted in staining intensity between preantral follicles, antral follicles, corpora lutea, and stroma classifications. No significant changes were observed in MMP and TIMP mRNA or extent of protein immunostaining with exposure to 3, 6, 9, or 12 weeks of SD, however protein was present and was localized to follicular and luteal steroidogenic cells.

Conclusions: Although MMPs appear to be involved in the normal ovarian estrus cycle at the protein level in hamsters, those examined in the present study are unlikely to be key players in the slow atrophy of tissue as seen in Siberian hamster ovarian regression.

Show MeSH
Related in: MedlinePlus