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Zinc supplementation protects against cadmium accumulation and cytotoxicity in Madin-Darby bovine kidney cells.

Zhang D, Liu J, Gao J, Shahzad M, Han Z, Wang Z, Li J, Sjölinder H - PLoS ONE (2014)

Bottom Line: Metallothioneins (MTs) are metal-binding proteins that play an essential role in heavy metal ion detoxification.We found that co-exposure to Zn2+ and Cd2+ synergistically enhanced RNA and protein expression of MT-1, MT-2, and the metal-regulatory transcription factor 1 in MDBK cells.Notably, addition of Zn2+ reduced the amounts of cytosolic Cd2+ detected following MDBK exposure to 10 μM Cd2+.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China.

ABSTRACT
Cadmium ions (Cd2+) have been reported to accumulate in bovine tissues, although Cd2+ cytotoxicity has not been investigated thoroughly in this species. Zinc ions (Zn2+) have been shown to antagonize the toxic effects of heavy metals such as Cd2+ in some systems. The present study investigated Cd2+ cytotoxicity in Madin-Darby bovine kidney (MDBK) epithelial cells, and explored whether this was modified by Zn2+. Exposure to Cd2+ led to a dose- and time-dependent increase in apoptotic cell death, with increased intracellular levels of reactive oxygen species and mitochondrial damage. Zn2+ supplementation alleviated Cd2+-induced cytotoxicity and this protective effect was more obvious when cells were exposed to a lower concentration of Cd2+ (10 μM), as compared to 50 μM Cd2+. This indicated that high levels of Cd2+ accumulation might induce irreversible damage in bovine kidney cells. Metallothioneins (MTs) are metal-binding proteins that play an essential role in heavy metal ion detoxification. We found that co-exposure to Zn2+ and Cd2+ synergistically enhanced RNA and protein expression of MT-1, MT-2, and the metal-regulatory transcription factor 1 in MDBK cells. Notably, addition of Zn2+ reduced the amounts of cytosolic Cd2+ detected following MDBK exposure to 10 μM Cd2+. These findings revealed a protective role of Zn2+ in counteracting Cd2+ uptake and toxicity in MDBK cells, indicating that this approach may provide a means to protect livestock from excessive Cd2+ accumulation.

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Effect of Zn2+ on Cd2+-induced accumulation of reactive oxygen species (ROS) in MDBK cells.(A) MDBK cells were treated with 10 μM CdCl2, alone or in combination with ZnCl2 (0, 10, or 50 μM), for 6 h. Intracellular ROS accumulation was assessed by DCFH-DA staining and imaged using a fluorescence microscope at ×200 magnification. (B) Cells were treated with Zn2+ and/or Cd2+ as indicated. Intracellular ROS was determined by flow cytometry following staining with DCFH-DA and the percentage of ROS-positive cells was quantified. The data represent the mean ± SD (n = 4). ##P<0.01, and ###P<0.001, compared to the medium-treated control group; *P<0.05 and **P<0.01 compared to the cells exposed to Cd2+ alone (10 or 50 μM).
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pone-0103427-g002: Effect of Zn2+ on Cd2+-induced accumulation of reactive oxygen species (ROS) in MDBK cells.(A) MDBK cells were treated with 10 μM CdCl2, alone or in combination with ZnCl2 (0, 10, or 50 μM), for 6 h. Intracellular ROS accumulation was assessed by DCFH-DA staining and imaged using a fluorescence microscope at ×200 magnification. (B) Cells were treated with Zn2+ and/or Cd2+ as indicated. Intracellular ROS was determined by flow cytometry following staining with DCFH-DA and the percentage of ROS-positive cells was quantified. The data represent the mean ± SD (n = 4). ##P<0.01, and ###P<0.001, compared to the medium-treated control group; *P<0.05 and **P<0.01 compared to the cells exposed to Cd2+ alone (10 or 50 μM).

Mentions: ROS accumulation plays both direct and indirect roles in inducing apoptosis [21]. We therefore analyzed the levels of ROS, as detected by DCFH-DA conversion to DCF, in MDBK cells exposed to Cd2+ and/or Zn2+ at the indicated concentrations. As shown in Fig. 2A, strong DCF fluorescence intensity was observed in cells treated with 10 μM Cd2+ for 6 h, whereas the addition of Zn2+ alone did not cause an obvious increase in ROS levels. Co-treatment with Cd2+ and Zn2+ led to a lower ROS level in the MDBK cells, as compared to treatment with Cd2+ alone.


Zinc supplementation protects against cadmium accumulation and cytotoxicity in Madin-Darby bovine kidney cells.

Zhang D, Liu J, Gao J, Shahzad M, Han Z, Wang Z, Li J, Sjölinder H - PLoS ONE (2014)

Effect of Zn2+ on Cd2+-induced accumulation of reactive oxygen species (ROS) in MDBK cells.(A) MDBK cells were treated with 10 μM CdCl2, alone or in combination with ZnCl2 (0, 10, or 50 μM), for 6 h. Intracellular ROS accumulation was assessed by DCFH-DA staining and imaged using a fluorescence microscope at ×200 magnification. (B) Cells were treated with Zn2+ and/or Cd2+ as indicated. Intracellular ROS was determined by flow cytometry following staining with DCFH-DA and the percentage of ROS-positive cells was quantified. The data represent the mean ± SD (n = 4). ##P<0.01, and ###P<0.001, compared to the medium-treated control group; *P<0.05 and **P<0.01 compared to the cells exposed to Cd2+ alone (10 or 50 μM).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4126686&req=5

pone-0103427-g002: Effect of Zn2+ on Cd2+-induced accumulation of reactive oxygen species (ROS) in MDBK cells.(A) MDBK cells were treated with 10 μM CdCl2, alone or in combination with ZnCl2 (0, 10, or 50 μM), for 6 h. Intracellular ROS accumulation was assessed by DCFH-DA staining and imaged using a fluorescence microscope at ×200 magnification. (B) Cells were treated with Zn2+ and/or Cd2+ as indicated. Intracellular ROS was determined by flow cytometry following staining with DCFH-DA and the percentage of ROS-positive cells was quantified. The data represent the mean ± SD (n = 4). ##P<0.01, and ###P<0.001, compared to the medium-treated control group; *P<0.05 and **P<0.01 compared to the cells exposed to Cd2+ alone (10 or 50 μM).
Mentions: ROS accumulation plays both direct and indirect roles in inducing apoptosis [21]. We therefore analyzed the levels of ROS, as detected by DCFH-DA conversion to DCF, in MDBK cells exposed to Cd2+ and/or Zn2+ at the indicated concentrations. As shown in Fig. 2A, strong DCF fluorescence intensity was observed in cells treated with 10 μM Cd2+ for 6 h, whereas the addition of Zn2+ alone did not cause an obvious increase in ROS levels. Co-treatment with Cd2+ and Zn2+ led to a lower ROS level in the MDBK cells, as compared to treatment with Cd2+ alone.

Bottom Line: Metallothioneins (MTs) are metal-binding proteins that play an essential role in heavy metal ion detoxification.We found that co-exposure to Zn2+ and Cd2+ synergistically enhanced RNA and protein expression of MT-1, MT-2, and the metal-regulatory transcription factor 1 in MDBK cells.Notably, addition of Zn2+ reduced the amounts of cytosolic Cd2+ detected following MDBK exposure to 10 μM Cd2+.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China.

ABSTRACT
Cadmium ions (Cd2+) have been reported to accumulate in bovine tissues, although Cd2+ cytotoxicity has not been investigated thoroughly in this species. Zinc ions (Zn2+) have been shown to antagonize the toxic effects of heavy metals such as Cd2+ in some systems. The present study investigated Cd2+ cytotoxicity in Madin-Darby bovine kidney (MDBK) epithelial cells, and explored whether this was modified by Zn2+. Exposure to Cd2+ led to a dose- and time-dependent increase in apoptotic cell death, with increased intracellular levels of reactive oxygen species and mitochondrial damage. Zn2+ supplementation alleviated Cd2+-induced cytotoxicity and this protective effect was more obvious when cells were exposed to a lower concentration of Cd2+ (10 μM), as compared to 50 μM Cd2+. This indicated that high levels of Cd2+ accumulation might induce irreversible damage in bovine kidney cells. Metallothioneins (MTs) are metal-binding proteins that play an essential role in heavy metal ion detoxification. We found that co-exposure to Zn2+ and Cd2+ synergistically enhanced RNA and protein expression of MT-1, MT-2, and the metal-regulatory transcription factor 1 in MDBK cells. Notably, addition of Zn2+ reduced the amounts of cytosolic Cd2+ detected following MDBK exposure to 10 μM Cd2+. These findings revealed a protective role of Zn2+ in counteracting Cd2+ uptake and toxicity in MDBK cells, indicating that this approach may provide a means to protect livestock from excessive Cd2+ accumulation.

Show MeSH
Related in: MedlinePlus