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Low Expression of Mfn2 Is Associated with Mitochondrial Damage and Apoptosis of Ovarian Tissues in the Premature Ovarian Failure Model.

Chen W, Xu X, Wang L, Bai G, Xiang W - PLoS ONE (2015)

Bottom Line: The follicles' number decreased within the tissue's stromal hyperplasia.Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed.Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased.

View Article: PubMed Central - PubMed

Affiliation: Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.

ABSTRACT

Background: This study aimed to construct a working model for detecting the mitochondrial damage and expression of Mfn2. It furthermore explored the pathogenesis of premature ovarian failure (POF) induced by cisplatin.

Method: Forty young female mice were divided randomly into two groups. The first was the treatment group intraperitoneally administered cisplatin (1.5mg/kg). The untreated control group was likewise injected with physiological saline for 10 days. One month later, we observed the ovarian weight and morphological changes, particularly the development of follicles and concentration of sex hormones. Immunohistochemistry and western blotting were used to measure the two groups. We later evaluated ovarian cell apoptosis with TUNEL and analyzed Bcl-2 and Bax levels. We used transmission electron microscopy in order to observe the ultrastructure of ovarian cells. The phosphomolybdic acid colorimetric method was used to measure the ATP content in the ovarian tissue. Finally, the mitochondrial membrane potential of ovarian cells was detected with JC-1 dye.

Results: The cisplatin resulted in a decline of body weight, reduced ovarian weight significantly, and resulted in disorders of the extrous cycle. The follicles' number decreased within the tissue's stromal hyperplasia. Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed. However, Mfn2 was present in the cell's cytoplasm in both groups. Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased. In addition, the ATP levels (35.2 ± 5.7 μmol/g) of the control group were significantly higher (13.5 ± 3.8 μmol/g). Lastly, an obvious impairment of mitochondrial function and structure was observed.

Conclusion: The intreperitoneal injection of cisplatin, when administered for 10 days, establishes a POF model. Thus, the above results suggest that lower expression of Mfn2 may be involved in the mechanism of premature ovarian failure by affecting both the mitochondria's energy metabolism and its apoptosis. This decides the termination of the follicles' development.

No MeSH data available.


Related in: MedlinePlus

Low Mfn2 expression is associated with cell apoptosis in mice's ovarian tissues of POF.A: Apoptosis was determined by TUNEL in the ovarian tissues (light staining in the cytotrophoblasts of the control group; deeper staining in the cisplatin group); B: The most representative images of western blot for Bcl-2 and Bax; C: Comparison of the Apoptosis Index in the ovarian cells; D: Comparison between Bcl-2 and Bax protein levels; E: Comparison of Mfn2, Bcl-2, and Bax protein levels. *P<0.05 vs control group.
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pone.0136421.g003: Low Mfn2 expression is associated with cell apoptosis in mice's ovarian tissues of POF.A: Apoptosis was determined by TUNEL in the ovarian tissues (light staining in the cytotrophoblasts of the control group; deeper staining in the cisplatin group); B: The most representative images of western blot for Bcl-2 and Bax; C: Comparison of the Apoptosis Index in the ovarian cells; D: Comparison between Bcl-2 and Bax protein levels; E: Comparison of Mfn2, Bcl-2, and Bax protein levels. *P<0.05 vs control group.

Mentions: We used TUNEL to detect cell apoptosis in finding the correlation between Mfn2 and cell apoptosis. Western blotting was used to analyze the expressions of anti-apoptotic protein Bcl-2 and apoptosis-promoting protein Bax. TUNEL-positive staining was observed in the ovarian tissue of both groups, and a light brown color was shown in samples from the control group (Fig 3A). However, a deeper brown color appeared in specimens from the cisplatin group (Fig 3A). The Apoptosis Index (AI) was 8.42%±2.35% in the control group and 34.01% ± 4.42% in the cisplatin group (Fig 3C) This suggests that the number of apoptotic cells in ovarian tissue from the cisplatin group was higher than that of the control group. In addition, Western blotting revealed that expression levels of Bax were increased in the cisplatin group (0.348±0.046) as compared with the control group (0.131±0.019) (Fig 3E). However, Bcl-2 was reduced in the cisplatin group (0.182±0.017) as compared to the control group (0.329±0.86) (Fig 3D). Protein loadings of three different samples from each group are shown in Fig 3B. One-way analysis of variance testing was used to address the correlation between Mfn2, Bcl-2 and Bax. Relative amounts of Mfn2 in the cisplatin group was positively correlated with Bcl-2, but negatively correlated with Bax levels (Fig 3E).


Low Expression of Mfn2 Is Associated with Mitochondrial Damage and Apoptosis of Ovarian Tissues in the Premature Ovarian Failure Model.

Chen W, Xu X, Wang L, Bai G, Xiang W - PLoS ONE (2015)

Low Mfn2 expression is associated with cell apoptosis in mice's ovarian tissues of POF.A: Apoptosis was determined by TUNEL in the ovarian tissues (light staining in the cytotrophoblasts of the control group; deeper staining in the cisplatin group); B: The most representative images of western blot for Bcl-2 and Bax; C: Comparison of the Apoptosis Index in the ovarian cells; D: Comparison between Bcl-2 and Bax protein levels; E: Comparison of Mfn2, Bcl-2, and Bax protein levels. *P<0.05 vs control group.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4556514&req=5

pone.0136421.g003: Low Mfn2 expression is associated with cell apoptosis in mice's ovarian tissues of POF.A: Apoptosis was determined by TUNEL in the ovarian tissues (light staining in the cytotrophoblasts of the control group; deeper staining in the cisplatin group); B: The most representative images of western blot for Bcl-2 and Bax; C: Comparison of the Apoptosis Index in the ovarian cells; D: Comparison between Bcl-2 and Bax protein levels; E: Comparison of Mfn2, Bcl-2, and Bax protein levels. *P<0.05 vs control group.
Mentions: We used TUNEL to detect cell apoptosis in finding the correlation between Mfn2 and cell apoptosis. Western blotting was used to analyze the expressions of anti-apoptotic protein Bcl-2 and apoptosis-promoting protein Bax. TUNEL-positive staining was observed in the ovarian tissue of both groups, and a light brown color was shown in samples from the control group (Fig 3A). However, a deeper brown color appeared in specimens from the cisplatin group (Fig 3A). The Apoptosis Index (AI) was 8.42%±2.35% in the control group and 34.01% ± 4.42% in the cisplatin group (Fig 3C) This suggests that the number of apoptotic cells in ovarian tissue from the cisplatin group was higher than that of the control group. In addition, Western blotting revealed that expression levels of Bax were increased in the cisplatin group (0.348±0.046) as compared with the control group (0.131±0.019) (Fig 3E). However, Bcl-2 was reduced in the cisplatin group (0.182±0.017) as compared to the control group (0.329±0.86) (Fig 3D). Protein loadings of three different samples from each group are shown in Fig 3B. One-way analysis of variance testing was used to address the correlation between Mfn2, Bcl-2 and Bax. Relative amounts of Mfn2 in the cisplatin group was positively correlated with Bcl-2, but negatively correlated with Bax levels (Fig 3E).

Bottom Line: The follicles' number decreased within the tissue's stromal hyperplasia.Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed.Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased.

View Article: PubMed Central - PubMed

Affiliation: Family Planning Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.

ABSTRACT

Background: This study aimed to construct a working model for detecting the mitochondrial damage and expression of Mfn2. It furthermore explored the pathogenesis of premature ovarian failure (POF) induced by cisplatin.

Method: Forty young female mice were divided randomly into two groups. The first was the treatment group intraperitoneally administered cisplatin (1.5mg/kg). The untreated control group was likewise injected with physiological saline for 10 days. One month later, we observed the ovarian weight and morphological changes, particularly the development of follicles and concentration of sex hormones. Immunohistochemistry and western blotting were used to measure the two groups. We later evaluated ovarian cell apoptosis with TUNEL and analyzed Bcl-2 and Bax levels. We used transmission electron microscopy in order to observe the ultrastructure of ovarian cells. The phosphomolybdic acid colorimetric method was used to measure the ATP content in the ovarian tissue. Finally, the mitochondrial membrane potential of ovarian cells was detected with JC-1 dye.

Results: The cisplatin resulted in a decline of body weight, reduced ovarian weight significantly, and resulted in disorders of the extrous cycle. The follicles' number decreased within the tissue's stromal hyperplasia. Moreover, E2 levels were reduced, and elevated gonadotropin levels were observed. However, Mfn2 was present in the cell's cytoplasm in both groups. Nevertheless, the Mfn2 levels and the expression of Bcl-2 were significantly decreased (p<0.05), but the expression of Bax and the apoptosis index (AI) was increased. In addition, the ATP levels (35.2 ± 5.7 μmol/g) of the control group were significantly higher (13.5 ± 3.8 μmol/g). Lastly, an obvious impairment of mitochondrial function and structure was observed.

Conclusion: The intreperitoneal injection of cisplatin, when administered for 10 days, establishes a POF model. Thus, the above results suggest that lower expression of Mfn2 may be involved in the mechanism of premature ovarian failure by affecting both the mitochondria's energy metabolism and its apoptosis. This decides the termination of the follicles' development.

No MeSH data available.


Related in: MedlinePlus