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Role of ATP-dependent K channels in the effects of erythropoietin in renal ischaemia injury.

Yilmaz TU, Yazihan N, Dalgic A, Kaya EE, Salman B, Kocak M, Akcil E - Indian J. Med. Res. (2015)

Bottom Line: Erythropoietin (EPO) has cytoprotective and anti-apoptotic effects in pathological conditions, including hypoxia and ischaemia-reperfusion injury.EPO (10 IU/ml) and diazoxide (100 μM) treatments significantly increased (p <0.01) whereas glibenclamide decreased ( p<0.05) HIF-1 α mRNA expression.Glibenclamide significantly ( p<0.01) decreased EPO induced HIF-1 α mRNA expression when compared with the EPO alone group.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine, Department of General Surgery, Kocaeli University, Kocaeli, Turkey.

ABSTRACT

Background & objectives: Erythropoietin (EPO) has cytoprotective and anti-apoptotic effects in pathological conditions, including hypoxia and ischaemia-reperfusion injury. One of the targets to protect against injury is ATP-dependent potassium (KATP ) channels. These channels could be involved in EPO induced ischaemic preconditoning like a protective effect. We evaluated the cell cytoprotective effects of EPO in relation to KATP channel activation in the renal tubular cell culture model under hypoxic/normoxic conditions.

Methods: Dose and time dependent effects of EPO, KATP channel blocker glibenclamide and KATP channel opener diazoxide on cellular proliferation were evaluated by colorimetric assay MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide] under normoxic and hypoxic conditions in human renal proximal tubular cell line (CRL-2830). Evaluation of the dose and time dependent effects of EPO, glibenclamide and diazoxide on apoptosis was done by caspase-3 activity levels. Hypoxia inducible factor-1 alpha (HIF-1 α) mRNA levels were measured by semi-quantative reverse transcription polymerase chain reaction (RT)-PCR. Kir 6.1 protein expresion was evalutaed by Western blot.

Results: Glibenclamide treatment decreased the number of living cells in a time and dose dependent manner, whereas EPO and diazoxide treatments increased. Glibenclamide (100 μM) treatment significantly blocked the anti-apoptotic effects of EPO (10 IU/ml) under both normoxic and hypoxic conditions. EPO (10 IU/ml) and diazoxide (100 μM) treatments significantly increased (p <0.01) whereas glibenclamide decreased ( p<0.05) HIF-1 α mRNA expression. Glibenclamide significantly ( p<0.01) decreased EPO induced HIF-1 α mRNA expression when compared with the EPO alone group.

Interpretation & conclusions: Our results showed that the cell proliferative, cytoprotective and anti-apoptotic effects of EPO were associated with KATP channels in the renal tubular cell culture model under hypoxic/normal conditions.

No MeSH data available.


Related in: MedlinePlus

Effects of different concentrations (1,5,10, 50 IU/ml) of erythropoietin (EPO) treatment on cell proliferation index in normoxia and hypoxia at 2, 24 and 48 h by the MTT assay. Data are presented as mean ± SE (n=40 observations).
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Figure 1: Effects of different concentrations (1,5,10, 50 IU/ml) of erythropoietin (EPO) treatment on cell proliferation index in normoxia and hypoxia at 2, 24 and 48 h by the MTT assay. Data are presented as mean ± SE (n=40 observations).

Mentions: Cell proliferation: In the cell culture model, with the appropriate media the cells proliferate, while death occurs as a result of end of cell life. The difference between proliferation and apoptosis determined the effects of our experiment. Effects of EPO, Gli, and Dia on proximal tubular cell proliferation were evaluated as functions of time in normoxia/hypoxia. EPO treatment increased cell proliferation in a dose- and time-dependent manner. Under normoxia, the number of cells increased in the course of time in all cell culture groups except Gli. A significant increase was seen in groups EPO 10 and EPO 50 between 2 and 48 h (P<0.001). The number of cells significantly increased at 48 h in groups EPO10 and EPO 50 when compared with the control (P<0.001). There was no significant difference between EPO 10 and EPO 50 groups. With the increase of dosage, the proliferative effect of EPO became more prominent at the 48th h (P<0.001) (Fig. 1). Under hypoxic conditions, the number of cells decreased over time in the control, EPO 1, and EPO 5 groups, but the differences were not significant. However, in the EPO 10 and EPO 50 groups, the number of cells increased over time but the differences were not significant. When we compared the number of cells at 48 h, EPO 10 and EPO 50 had a significantly increased number of cells as compared to the control group (P<0.05) (Fig. 1).


Role of ATP-dependent K channels in the effects of erythropoietin in renal ischaemia injury.

Yilmaz TU, Yazihan N, Dalgic A, Kaya EE, Salman B, Kocak M, Akcil E - Indian J. Med. Res. (2015)

Effects of different concentrations (1,5,10, 50 IU/ml) of erythropoietin (EPO) treatment on cell proliferation index in normoxia and hypoxia at 2, 24 and 48 h by the MTT assay. Data are presented as mean ± SE (n=40 observations).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525406&req=5

Figure 1: Effects of different concentrations (1,5,10, 50 IU/ml) of erythropoietin (EPO) treatment on cell proliferation index in normoxia and hypoxia at 2, 24 and 48 h by the MTT assay. Data are presented as mean ± SE (n=40 observations).
Mentions: Cell proliferation: In the cell culture model, with the appropriate media the cells proliferate, while death occurs as a result of end of cell life. The difference between proliferation and apoptosis determined the effects of our experiment. Effects of EPO, Gli, and Dia on proximal tubular cell proliferation were evaluated as functions of time in normoxia/hypoxia. EPO treatment increased cell proliferation in a dose- and time-dependent manner. Under normoxia, the number of cells increased in the course of time in all cell culture groups except Gli. A significant increase was seen in groups EPO 10 and EPO 50 between 2 and 48 h (P<0.001). The number of cells significantly increased at 48 h in groups EPO10 and EPO 50 when compared with the control (P<0.001). There was no significant difference between EPO 10 and EPO 50 groups. With the increase of dosage, the proliferative effect of EPO became more prominent at the 48th h (P<0.001) (Fig. 1). Under hypoxic conditions, the number of cells decreased over time in the control, EPO 1, and EPO 5 groups, but the differences were not significant. However, in the EPO 10 and EPO 50 groups, the number of cells increased over time but the differences were not significant. When we compared the number of cells at 48 h, EPO 10 and EPO 50 had a significantly increased number of cells as compared to the control group (P<0.05) (Fig. 1).

Bottom Line: Erythropoietin (EPO) has cytoprotective and anti-apoptotic effects in pathological conditions, including hypoxia and ischaemia-reperfusion injury.EPO (10 IU/ml) and diazoxide (100 μM) treatments significantly increased (p <0.01) whereas glibenclamide decreased ( p<0.05) HIF-1 α mRNA expression.Glibenclamide significantly ( p<0.01) decreased EPO induced HIF-1 α mRNA expression when compared with the EPO alone group.

View Article: PubMed Central - PubMed

Affiliation: School of Medicine, Department of General Surgery, Kocaeli University, Kocaeli, Turkey.

ABSTRACT

Background & objectives: Erythropoietin (EPO) has cytoprotective and anti-apoptotic effects in pathological conditions, including hypoxia and ischaemia-reperfusion injury. One of the targets to protect against injury is ATP-dependent potassium (KATP ) channels. These channels could be involved in EPO induced ischaemic preconditoning like a protective effect. We evaluated the cell cytoprotective effects of EPO in relation to KATP channel activation in the renal tubular cell culture model under hypoxic/normoxic conditions.

Methods: Dose and time dependent effects of EPO, KATP channel blocker glibenclamide and KATP channel opener diazoxide on cellular proliferation were evaluated by colorimetric assay MTT [3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide] under normoxic and hypoxic conditions in human renal proximal tubular cell line (CRL-2830). Evaluation of the dose and time dependent effects of EPO, glibenclamide and diazoxide on apoptosis was done by caspase-3 activity levels. Hypoxia inducible factor-1 alpha (HIF-1 α) mRNA levels were measured by semi-quantative reverse transcription polymerase chain reaction (RT)-PCR. Kir 6.1 protein expresion was evalutaed by Western blot.

Results: Glibenclamide treatment decreased the number of living cells in a time and dose dependent manner, whereas EPO and diazoxide treatments increased. Glibenclamide (100 μM) treatment significantly blocked the anti-apoptotic effects of EPO (10 IU/ml) under both normoxic and hypoxic conditions. EPO (10 IU/ml) and diazoxide (100 μM) treatments significantly increased (p <0.01) whereas glibenclamide decreased ( p<0.05) HIF-1 α mRNA expression. Glibenclamide significantly ( p<0.01) decreased EPO induced HIF-1 α mRNA expression when compared with the EPO alone group.

Interpretation & conclusions: Our results showed that the cell proliferative, cytoprotective and anti-apoptotic effects of EPO were associated with KATP channels in the renal tubular cell culture model under hypoxic/normal conditions.

No MeSH data available.


Related in: MedlinePlus