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Microcystin-LR Induced Apoptosis in Rat Sertoli Cells via the Mitochondrial Caspase-Dependent Pathway: Role of Reactive Oxygen Species

View Article: PubMed Central - PubMed

ABSTRACT

Microcystins (MCs), the secondary metabolites of blue-green algae, are ubiquitous and major cyanotoxin contaminants. Besides the hepatopancreas/liver, the reproductive system is regarded as the most important target organ for MCs. Although reactive oxygen species (ROS) have been implicated in MCs-induced reproductive toxicity, the role of MCs in this pathway remains unclear. In the present study, Sertoli cells were employed to investigate apoptotic death involved in male reproductive toxicity of microcystin-LR (MC-LR). After exposure to various concentrations of MC-LR for 24 h, the growth of Sertoli cells was concentration-dependently decreased with an IC50 of ~32 μg/mL. Mitochondria-mediated apoptotic changes were observed in Sertoli cells exposed to 8, 16, and 32 μg/mL MC-LR including the increased expression of caspase pathway proteins, collapse of mitochondrial membrane potential (MMP), and generation of ROS. Pretreatment with a global caspase inhibitor was found to depress the activation of caspases, and eventually increased the survival rate of Sertoli cells, implying that the mitochondrial caspases pathway is involved in MC-LR-induced apoptosis. Furthermore, N-acetyl-l-cysteine attenuated the MC-LR-induced intracellular ROS generation, MMP collapse and cytochrome c release, resulting in the inhibition of apoptosis. Taken together, the observed results suggested that MC-LR induced apoptotic death of Sertoli cells by the activation of mitochondrial caspases cascade, while its effects on the ROS-mediated signaling pathway may contribute toward the initiation of mitochondrial dysfunction.

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MC-LR induced apoptosis of rat Sertoli cells. After cells were treated with MC-LR for 24 h, cell apoptosis rate was determined by flow cytometry after annexin V-FITC/PI staining (A–E) and data were expressed as mean ± SEM (F). (A) Control group; (B) 8 μg/mL MC-LR; (C) 16 μg/mL MC-LR; (D) 32 μg/mL MC-LR, (E) 50 μM zVADfmk + 32 μg/mL MC-LR (n = 3). *P < 0.05 vs. control group; #P < 0.05 vs. 32 μg/mL MC-LR.
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Figure 2: MC-LR induced apoptosis of rat Sertoli cells. After cells were treated with MC-LR for 24 h, cell apoptosis rate was determined by flow cytometry after annexin V-FITC/PI staining (A–E) and data were expressed as mean ± SEM (F). (A) Control group; (B) 8 μg/mL MC-LR; (C) 16 μg/mL MC-LR; (D) 32 μg/mL MC-LR, (E) 50 μM zVADfmk + 32 μg/mL MC-LR (n = 3). *P < 0.05 vs. control group; #P < 0.05 vs. 32 μg/mL MC-LR.

Mentions: To determine the apoptosis index of Sertoli cells, flow cytometry was done after annexin-V FITC and PI staining. As shown in Figure 2, the apoptosis index of Sertoli cells was significantly higher in the MC-LR group than that in the control group.


Microcystin-LR Induced Apoptosis in Rat Sertoli Cells via the Mitochondrial Caspase-Dependent Pathway: Role of Reactive Oxygen Species
MC-LR induced apoptosis of rat Sertoli cells. After cells were treated with MC-LR for 24 h, cell apoptosis rate was determined by flow cytometry after annexin V-FITC/PI staining (A–E) and data were expressed as mean ± SEM (F). (A) Control group; (B) 8 μg/mL MC-LR; (C) 16 μg/mL MC-LR; (D) 32 μg/mL MC-LR, (E) 50 μM zVADfmk + 32 μg/mL MC-LR (n = 3). *P < 0.05 vs. control group; #P < 0.05 vs. 32 μg/mL MC-LR.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5016609&req=5

Figure 2: MC-LR induced apoptosis of rat Sertoli cells. After cells were treated with MC-LR for 24 h, cell apoptosis rate was determined by flow cytometry after annexin V-FITC/PI staining (A–E) and data were expressed as mean ± SEM (F). (A) Control group; (B) 8 μg/mL MC-LR; (C) 16 μg/mL MC-LR; (D) 32 μg/mL MC-LR, (E) 50 μM zVADfmk + 32 μg/mL MC-LR (n = 3). *P < 0.05 vs. control group; #P < 0.05 vs. 32 μg/mL MC-LR.
Mentions: To determine the apoptosis index of Sertoli cells, flow cytometry was done after annexin-V FITC and PI staining. As shown in Figure 2, the apoptosis index of Sertoli cells was significantly higher in the MC-LR group than that in the control group.

View Article: PubMed Central - PubMed

ABSTRACT

Microcystins (MCs), the secondary metabolites of blue-green algae, are ubiquitous and major cyanotoxin contaminants. Besides the hepatopancreas/liver, the reproductive system is regarded as the most important target organ for MCs. Although reactive oxygen species (ROS) have been implicated in MCs-induced reproductive toxicity, the role of MCs in this pathway remains unclear. In the present study, Sertoli cells were employed to investigate apoptotic death involved in male reproductive toxicity of microcystin-LR (MC-LR). After exposure to various concentrations of MC-LR for 24 h, the growth of Sertoli cells was concentration-dependently decreased with an IC50 of ~32 &mu;g/mL. Mitochondria-mediated apoptotic changes were observed in Sertoli cells exposed to 8, 16, and 32 &mu;g/mL MC-LR including the increased expression of caspase pathway proteins, collapse of mitochondrial membrane potential (MMP), and generation of ROS. Pretreatment with a global caspase inhibitor was found to depress the activation of caspases, and eventually increased the survival rate of Sertoli cells, implying that the mitochondrial caspases pathway is involved in MC-LR-induced apoptosis. Furthermore, N-acetyl-l-cysteine attenuated the MC-LR-induced intracellular ROS generation, MMP collapse and cytochrome c release, resulting in the inhibition of apoptosis. Taken together, the observed results suggested that MC-LR induced apoptotic death of Sertoli cells by the activation of mitochondrial caspases cascade, while its effects on the ROS-mediated signaling pathway may contribute toward the initiation of mitochondrial dysfunction.

No MeSH data available.


Related in: MedlinePlus