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Inhibition of gene expression of organic cation/carnitine transporter and antioxidant enzymes in oxazaphosphorines-induced acute cardiomyopathic rat models.

Sayed-Ahmed MM, Aldelemy ML, Hafez MM, Al-Shabanah OA - Oxid Med Cell Longev (2012)

Bottom Line: It is well documented that high therapeutic doses of oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IFO), are associated with cardiomyopathy.In cardiac and kidney tissues, CP and IFO significantly decreased mRNA and protein expression of OCTN2.Data from this study suggest that: (1) Oxazaphosphorines decreased myocardial carnitine content following the inhibition of OCTN2 mRNA and protein expression in cardiac tissues. (2) Oxazaphosphorine therapy increased urinary loss of carnitine secondary to the inhibition of OCTN2 mRNA and protein expression in proximal tubules of the kidney. (3) Carnitine supplementation attenuates CP but not IFO-induced inhibition of OCTN2 mRNA and protein expression in heart and kidney tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia. sayedahmedmm@hotmail.com

ABSTRACT
It is well documented that high therapeutic doses of oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IFO), are associated with cardiomyopathy. This study investigated whether oxazaphosphorines alter the expression of organic cation/carnitine transporter (OCTN2) and antioxidant genes and if so, whether these alterations contribute to CP and IFO-induced cardiotoxicity. Adult male Wistar albino rats were assigned to one of six treatment groups namely, control, L carnitine, CP, IFO, CP plus L carnitine and IFO plus L carnitine. In cardiac and kidney tissues, CP and IFO significantly decreased mRNA and protein expression of OCTN2. Oxazaphosphorines significantly increased serum acyl-carnitine/free carnitine ratio and urinary carnitine excretion and significantly decreased total carnitine in cardiac tissues. Interestingly, carnitine supplementation completely reversed the biochemical and gene expression changes-induced by oxazaphosphorines to the control values, except OCTN2 expression remained inhibited by IFO. Data from this study suggest that: (1) Oxazaphosphorines decreased myocardial carnitine content following the inhibition of OCTN2 mRNA and protein expression in cardiac tissues. (2) Oxazaphosphorine therapy increased urinary loss of carnitine secondary to the inhibition of OCTN2 mRNA and protein expression in proximal tubules of the kidney. (3) Carnitine supplementation attenuates CP but not IFO-induced inhibition of OCTN2 mRNA and protein expression in heart and kidney tissues.

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Effects of cyclophosphamide (CP), ifosfamide (IFO), L carnitine (LC) and their combination on urinary carnitine excretion in rats. Rats were randomly divided into 6 different groups of 10 animals each: control, L carnitine, CP, IFO, CP carnitine supplemented, and IFO carnitine supplemented. Carnitine supplementation was induced in rats by daily intraperitoneal injection of L carnitine (200 mg/kg/day) for 10 successive days. CP cardiotoxicity was induced in rats by administration of a single dose of CP (200 mg/kg). IFO cardiotoxicity was induced in rats by administration of IFO (50 mg/kg/day, I.P.) for 5 successive days. CP-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days after a single dose of CP (200 mg/kg). IFO-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days concomitant with IFO (50 mg/kg/day, I.P.). Immediately after the last dose of the treatment protocol, 24 hour-urine was collected for monitoring urinary carnitine excretion. Data are presented as mean ± S.E.M. (n = 10). *, #, and $ indicate significant change from control, CP and IFO, respectively, at P < 0.05 using ANOVA followed by Tukey-Kramer as a post-ANOVA test.
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fig4: Effects of cyclophosphamide (CP), ifosfamide (IFO), L carnitine (LC) and their combination on urinary carnitine excretion in rats. Rats were randomly divided into 6 different groups of 10 animals each: control, L carnitine, CP, IFO, CP carnitine supplemented, and IFO carnitine supplemented. Carnitine supplementation was induced in rats by daily intraperitoneal injection of L carnitine (200 mg/kg/day) for 10 successive days. CP cardiotoxicity was induced in rats by administration of a single dose of CP (200 mg/kg). IFO cardiotoxicity was induced in rats by administration of IFO (50 mg/kg/day, I.P.) for 5 successive days. CP-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days after a single dose of CP (200 mg/kg). IFO-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days concomitant with IFO (50 mg/kg/day, I.P.). Immediately after the last dose of the treatment protocol, 24 hour-urine was collected for monitoring urinary carnitine excretion. Data are presented as mean ± S.E.M. (n = 10). *, #, and $ indicate significant change from control, CP and IFO, respectively, at P < 0.05 using ANOVA followed by Tukey-Kramer as a post-ANOVA test.

Mentions: Figure 4 shows the effects of oxazaphosphorines, L carnitine, and their combination on urinary carnitine excretion in rats. Treatment with a single dose of CP and 5 doses of IFO resulted in a significant 132 and 268% increase in carnitine excretion, respectively, as compared to the control group. On the other hand, daily administration of L carnitine alone for 10 successive days resulted in nonsignificant change in urinary carnitine excretion. Interestingly, administration of L carnitine in combination with CP and IFO resulted in a complete reversal of the increase in carnitine excretion, induced by CP and IFO, to the control values. To explain the effects of oxazaphosphorines on carnitine reabsorption/secretion rate, the mRNA and protein expression of OCTN2 gene was measured in kidney tissues using RT-PCR and western blot analysis, respectively (Figure 5). Administration of either CP or IFO alone significantly decreased the expression of OCTN2 on the mRNA (a) and protein (b) levels in kidney tissues. A significant 32 and 87% decrease were obtained after CP and IFO, respectively, as compared to the control group. Similarly, CP and IFO significantly decreased OCTN2 protein expression by 45 and 57%, respectively, as compared to the control group. Daily administration of L carnitine alone for 10 successive days resulted in nonsignificant change in OCTN2 mRNA and protein expression. Interestingly, administration of L carnitine for 5 days before and 5 days after a single dose of CP resulted in a complete reversal of CP-induced decrease in OCTN2 mRNA and protein expression to the control values. Conversely, administration of L carnitine to IFO-treated rats did not affect IFO-induced decrease of OCTN2 expression.


Inhibition of gene expression of organic cation/carnitine transporter and antioxidant enzymes in oxazaphosphorines-induced acute cardiomyopathic rat models.

Sayed-Ahmed MM, Aldelemy ML, Hafez MM, Al-Shabanah OA - Oxid Med Cell Longev (2012)

Effects of cyclophosphamide (CP), ifosfamide (IFO), L carnitine (LC) and their combination on urinary carnitine excretion in rats. Rats were randomly divided into 6 different groups of 10 animals each: control, L carnitine, CP, IFO, CP carnitine supplemented, and IFO carnitine supplemented. Carnitine supplementation was induced in rats by daily intraperitoneal injection of L carnitine (200 mg/kg/day) for 10 successive days. CP cardiotoxicity was induced in rats by administration of a single dose of CP (200 mg/kg). IFO cardiotoxicity was induced in rats by administration of IFO (50 mg/kg/day, I.P.) for 5 successive days. CP-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days after a single dose of CP (200 mg/kg). IFO-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days concomitant with IFO (50 mg/kg/day, I.P.). Immediately after the last dose of the treatment protocol, 24 hour-urine was collected for monitoring urinary carnitine excretion. Data are presented as mean ± S.E.M. (n = 10). *, #, and $ indicate significant change from control, CP and IFO, respectively, at P < 0.05 using ANOVA followed by Tukey-Kramer as a post-ANOVA test.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369488&req=5

fig4: Effects of cyclophosphamide (CP), ifosfamide (IFO), L carnitine (LC) and their combination on urinary carnitine excretion in rats. Rats were randomly divided into 6 different groups of 10 animals each: control, L carnitine, CP, IFO, CP carnitine supplemented, and IFO carnitine supplemented. Carnitine supplementation was induced in rats by daily intraperitoneal injection of L carnitine (200 mg/kg/day) for 10 successive days. CP cardiotoxicity was induced in rats by administration of a single dose of CP (200 mg/kg). IFO cardiotoxicity was induced in rats by administration of IFO (50 mg/kg/day, I.P.) for 5 successive days. CP-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days after a single dose of CP (200 mg/kg). IFO-carnitine-supplemented rats were given the same doses of L carnitine (200 mg/kg/day) for 5 days before and 5 days concomitant with IFO (50 mg/kg/day, I.P.). Immediately after the last dose of the treatment protocol, 24 hour-urine was collected for monitoring urinary carnitine excretion. Data are presented as mean ± S.E.M. (n = 10). *, #, and $ indicate significant change from control, CP and IFO, respectively, at P < 0.05 using ANOVA followed by Tukey-Kramer as a post-ANOVA test.
Mentions: Figure 4 shows the effects of oxazaphosphorines, L carnitine, and their combination on urinary carnitine excretion in rats. Treatment with a single dose of CP and 5 doses of IFO resulted in a significant 132 and 268% increase in carnitine excretion, respectively, as compared to the control group. On the other hand, daily administration of L carnitine alone for 10 successive days resulted in nonsignificant change in urinary carnitine excretion. Interestingly, administration of L carnitine in combination with CP and IFO resulted in a complete reversal of the increase in carnitine excretion, induced by CP and IFO, to the control values. To explain the effects of oxazaphosphorines on carnitine reabsorption/secretion rate, the mRNA and protein expression of OCTN2 gene was measured in kidney tissues using RT-PCR and western blot analysis, respectively (Figure 5). Administration of either CP or IFO alone significantly decreased the expression of OCTN2 on the mRNA (a) and protein (b) levels in kidney tissues. A significant 32 and 87% decrease were obtained after CP and IFO, respectively, as compared to the control group. Similarly, CP and IFO significantly decreased OCTN2 protein expression by 45 and 57%, respectively, as compared to the control group. Daily administration of L carnitine alone for 10 successive days resulted in nonsignificant change in OCTN2 mRNA and protein expression. Interestingly, administration of L carnitine for 5 days before and 5 days after a single dose of CP resulted in a complete reversal of CP-induced decrease in OCTN2 mRNA and protein expression to the control values. Conversely, administration of L carnitine to IFO-treated rats did not affect IFO-induced decrease of OCTN2 expression.

Bottom Line: It is well documented that high therapeutic doses of oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IFO), are associated with cardiomyopathy.In cardiac and kidney tissues, CP and IFO significantly decreased mRNA and protein expression of OCTN2.Data from this study suggest that: (1) Oxazaphosphorines decreased myocardial carnitine content following the inhibition of OCTN2 mRNA and protein expression in cardiac tissues. (2) Oxazaphosphorine therapy increased urinary loss of carnitine secondary to the inhibition of OCTN2 mRNA and protein expression in proximal tubules of the kidney. (3) Carnitine supplementation attenuates CP but not IFO-induced inhibition of OCTN2 mRNA and protein expression in heart and kidney tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia. sayedahmedmm@hotmail.com

ABSTRACT
It is well documented that high therapeutic doses of oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IFO), are associated with cardiomyopathy. This study investigated whether oxazaphosphorines alter the expression of organic cation/carnitine transporter (OCTN2) and antioxidant genes and if so, whether these alterations contribute to CP and IFO-induced cardiotoxicity. Adult male Wistar albino rats were assigned to one of six treatment groups namely, control, L carnitine, CP, IFO, CP plus L carnitine and IFO plus L carnitine. In cardiac and kidney tissues, CP and IFO significantly decreased mRNA and protein expression of OCTN2. Oxazaphosphorines significantly increased serum acyl-carnitine/free carnitine ratio and urinary carnitine excretion and significantly decreased total carnitine in cardiac tissues. Interestingly, carnitine supplementation completely reversed the biochemical and gene expression changes-induced by oxazaphosphorines to the control values, except OCTN2 expression remained inhibited by IFO. Data from this study suggest that: (1) Oxazaphosphorines decreased myocardial carnitine content following the inhibition of OCTN2 mRNA and protein expression in cardiac tissues. (2) Oxazaphosphorine therapy increased urinary loss of carnitine secondary to the inhibition of OCTN2 mRNA and protein expression in proximal tubules of the kidney. (3) Carnitine supplementation attenuates CP but not IFO-induced inhibition of OCTN2 mRNA and protein expression in heart and kidney tissues.

Show MeSH
Related in: MedlinePlus