Carnitine Supplementation Attenuates Sunitinib-Induced Inhibition of AMP-Activated Protein Kinase Downstream Signals in Cardiac Tissues.

This study has been initiated to investigate whether sunitinib (SUN) alters the expression of key genes engaged in mitochondrial transport and oxidation of long chain fatty acids (LCFA), and if so, whether these alterations should be viewed as a mechanism of SUN-induced cardiotoxicity, and to explore the molecular mechanisms whereby carnitine supplementation could attenuate SUN-induced cardiotoxicity. Adult male Wister albino rats were assigned to one of the four treatment groups: Rats in group 1 received no treatment but free access to tap water for 28 days. Rats in group 2 received L-carnitine (200 mg/kg/day) in drinking water for 28 days. Rats in group 3 received SUN (25 mg/kg/day) in drinking water for 28 days. Rats in group 4 received the same doses of L-carnitine and SUN in drinking water for 28 days. Treatment with SUN significantly increased heart weight, cardiac index, and cardiotoxicity enzymatic indices, as well as severe histopathological changes. Moreover, SUN significantly decreased level of adenosine monophosphate-activated protein kinase (AMPKα2), total carnitine, adenosine triphosphate (ATP) and carnitine palmitoyltransferase I (CPT I) expression and significantly increased acetyl-CoA carboxylase-2 (ACC2) expression and malonyl-CoA level in cardiac tissues. Interestingly, carnitine supplementation resulted in a complete reversal of all the biochemical, gene expression and histopathological changes-induced by SUN to the control values. In conclusion, data from this study suggest that SUN inhibits AMPK downstream signaling with the consequent inhibition of mitochondrial transport of LCFA and energy production in cardiac tissues. Carnitine supplementation attenuates SUN-induced cardiotoxicity.

Neuro-protective effect of rutin against Cisplatin-induced neurotoxic rat model.

BACKGROUND: Cisplatin is widely used chemotherapeutic agent for cancer treatment with limited uses due to its neurotoxic side effect. The aim of this study was to determine the potential preventive effects of rutin on the brain of cisplatin- neurotoxic rat model. METHODS: Forty rats were divided into four groups. Group-1 (control group) was intra-peritoneal (IP) injected with 2.5 ml/kg saline. Group-2 (rutin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days. Group-3 (cisplatin group) was IP received 5 mg/kg cisplatin single dose. Group-4 (rutin and cisplatin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days with a single dose of 5 mg/kg cisplatin IP on day ten. Brain tissues from frontal cortex was used to extract RNA, the gene expression levels of paraoxonase-1 (PON-1), PON-2, PON-3, peroxisome proliferator-activated receptor delta (PPAR-δ), and glutathione peroxidase (GPx) was investigated by Real-time PCR. RESULTS: Cisplatin significantly decreased the expression levels of PON-1, PON-3, PPAR-δ and GPX whereas significantly increased PON-2 expression levels. Co-administration of Rutin prevented the cisplatin-induced toxicity by restoring the alteration in the studied genes to normal values as in the control group. CONCLUSION: This study showed that Rutin has neuroprotective effect and reduces cisplatin- neurotoxicity with possible mechanism via the antioxidant pathway.

Effect of ginseng extract on the TGF-ß1 signaling pathway in CCl4-induced liver fibrosis in rats.

BACKGROUND: Liver diseases are major global health problems. Ginseng extract has antioxidant, immune-modulatory and anti-inflammatory activities. This study investigated the effect of ginseng extract on carbon tetrachloride (CCl4)-induced liver fibrosis in rats. METHODS: Male Wistar rats were divided into four groups: control group, ginseng group, CCl4 group and CCl4 + ginseng group. Liver injury was induced by the intraperitoneal (I.P) injection of 3 ml/kg CCl4 (30% in olive oil) weekly for 8 weeks. The control group was I.P injected with olive oil. The expression of genes encoding transforming growth factor beta (TGF-ß), type I TGF-ß receptor (TßR-1), type II TGF-ß receptor (TßR-II), mothers against decapentaplegic homolog 2 (Smad2), Smad3, Smad4, matrix metalloproteinase 2 (MMP2), MMP9, tissue inhibitor matrix metalloproteinase-1 (TIMP-1), Collagen 1a2 (Col1a2), Collagen 3a1 (Col3a1), interleukin-8 (IL-8) and interleukin -10 (IL-10) were measured by real-time PCR. RESULTS: Treatment with ginseng extract decreased hepatic fat deposition and lowered hepatic reticular fiber accumulation compared with the CCl4 group. The CCl4 group showed a significant increase in hepatotoxicity biomarkers and up-regulation of the expression of genes encoding TGF-ß, TßR-I, TßR-II, MMP2, MMP9, Smad-2,-3, -4, and IL-8 compared with the control group. However, CCl4 administration resulted in the significant down-regulation of IL-10 mRNA expression compared with the control group. Interestingly, ginseng extract supplementation completely reversed the biochemical markers of hepatotoxicity and the gene expression alterations induced by CCl4. CONCLUSION: ginseng extract had an anti-fibrosis effect via the regulation of the TGF-ß1/Smad signaling pathway in the CCl4-induced liver fibrosis model. The major target was the inhibition of the expression of TGF-ß1, Smad2, and Smad3.

The tyrosine kinase inhibitor tyrphostin AG126 reduces activation of inflammatory cells and increases Foxp3+ regulatory T cells during pathogenesis of rheumatoid arthritis.

Protein tyrosine kinases are key mediators of the signal transduction cascades that control expression of many genes involved in the induction of inflammation caused by arthritis. Here we investigate the effect of the tyrosine kinase inhibitor tyrphostin AG126 on a mouse model of adjuvant-induced arthritis (AIA). We report that when given at 5mg/kg i.p. every 48h from days 0-21, AG126 exerts potent anti-arthritic effects. Further, we investigated the role of AG126 on the key mediators of arthritic inflammation, namely, edema, arthritic score, presence of immunophenotypes including Foxp3+, CD4+Foxp3+, and CD25+Foxp3+ T regulatory (Treg) cells, as well as pro- and anti-inflammatory mediators. AG126 treatment significantly attenuated the severity of AIA and caused a substantial reduction in the percentage of CD2+, CD3+, CD4+, CD8+, CD23+, CD80+, CD86+ CD122+, CD195+, TCRß+, and GITR+ cells in whole blood. Moreover, administration of AG126 under arthritis-inducing conditions resulted in suppression of IL-17A+, IFN-γ+, CD4+ and CD25+ populations while causing an increase in the Foxp3+, CD4+Foxp3+, and CD25+Foxp3+ Treg populations in the spleen. In addition, RT-PCR analysis revealed increased expression of CD4, CD8, IL-17A, IFN-γ, TNF-α, and NF-κB p65 mRNAs and decreased IL-4 mRNA in the arthritic control (AC) mice, while treatment of animals with AG126 reversed these effects. Western blot analysis confirmed the decreased expression of IL-17, GITR, NF-κB p65 proteins and increased Foxp3 and IL-4 proteins following AG126 treatment of knee tissue. Thus, our findings provide new evidence that inhibition of protein tyrosine kinase activity decreases the progression of arthritis.

Inhibition of gene expression of carnitine palmitoyltransferase I and heart fatty acid binding protein in cyclophosphamide and ifosfamide-induced acute cardiotoxic rat models.

This study investigated whether cyclophosphamide (CP) and ifosfamide (IFO) therapy alters the expression of the key genes engaged in long-chain fatty acid (LCFA) oxidation outside rat heart mitochondria, and if so, whether these alterations should be viewed as a mechanism during CP- and IFO-induced cardiotoxicity. Adult male Wistar albino rats were assigned to one of the six treatment groups: Rats in group 1 (control) and group 2 (L-carnitine) were injected intraperitoneal (i.p.) with normal saline and L-carnitine (200 mg/kg/day), respectively, for 10 successive days. Animals in group 3 (CP group) were injected i.p. with normal saline for 5 days before and 5 days after a single dose of CP (200 mg/kg, i.p.). Rats in group 4 (IFO group) received normal saline for 5 successive days followed by IFO (50 mg/kg/day, i.p.) for 5 successive days. Rats in group 5 (CP-carnitine supplemented) were given the same doses of L-carnitine as group 2 for 5 days before and 5 days after a single dose of CP as group 3. Rats in group 6 (IFO-carnitine supplemented) were given the same doses of L-carnitine as group 2 for 5 days before and 5 days concomitant with IFO as group 4. Immediately, after the last dose of the treatment protocol, blood samples were withdrawn and animals were killed for biochemical, histopathological and gene expression studies. Treatment with CP and IFO significantly decreased expression of heart fatty acid binding protein (H-FABP) and carnitine palmitoyltransferase I (CPT I) genes in cardiac tissues. Moreover, CP but not IFO significantly increased acetyl-CoA carboxylase2 mRNA expression. Conversely, IFO but not CP significantly decreased mRNA expression of malonyl-CoA decarboxylase. Both CP and IFO significantly increased serum lactate dehydrogenase, creatine kinase isoenzyme MB and malonyl-CoA content and histopathological lesions in cardiac tissues. Interestingly, carnitine supplementation completely reversed all the biochemical, histopathological and gene expression changes induced by CP and IFO to the control values, except CPT I mRNA, and protein expression remained inhibited by IFO. Data from the current study suggest, for the first time, that (1) CP and IFO therapy is associated with the inhibition of the expression of H-FABP and CPT I genes in cardiac tissues with the consequent inhibition of mitochondrial transport and oxidation of LCFA. (2) The progressive increase in cardiotoxicity enzymatic indices and the decrease in H-FABP and CPT I expression may point to the possible contribution of these genes to CP- and IFO-induced cardiotoxicity.

Protective effect of rutin on the antioxidant genes expression in hypercholestrolemic male Westar rat.

BACKGROUND: High-cholesterol diet (HCD) increases the oxidative stress in different tissues leading to many diseases. Rutin (RT) is a natural flavonoid (vitamin p), which possesses an antioxidant activity with protective potential. The present study aimed to examine the potential effects of rutin on hypercholesterolemia-induced hepatotoxicity in rat. METHODS: Male Wistar rats were divided into four groups: GI) control (Rat chow), GII) Rutin (0.2% in rat chow), GIII) HCD (1% cholesterol and 0.5% cholic acid in rat chow) and GIV) rutin (0.2%) + HCD. RESULTS: Rutin in combination with HCD induced a significant protective effect against the hepatotoxicity by reducing the plasma level of alanine transaminase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL). The HCD (GII) showed a decrease in glutathione peroxidase (GPx), glutathione reductase (GR) and increase in glutathione S transferase α (GSTα), sulfiredoxin-1(Srx1), glutamate-cysteine ligase (GCL) and paraoxonase-1(PON-1) genes expression levels. CONCLUSION: Treatment with rutin reversed all the altered genes induced by HCD nearly to the control levels. The present study concluded that the HCD feedings altered the expression levels of some genes involved in the oxidative stress pathway resulting in DNA damage and hepatotoxicity. Rutin have a hepatoprotective effect through the mechanism of enhancing the antioxidant effect via amelioration of oxidative stress genes.

Downregulation of oxidative and nitrosative apoptotic signaling by L-carnitine in Ifosfamide-induced Fanconi syndrome rat model.

It is well documented that ifosfamide (IFO) therapy is associated with sever nephropathy in the form of Fanconi syndrome. Although oxidative stress has been reported as a major player in IFO-induced Fanconi syndrome, no mechanism for this effect has been ascertained. Therefore, this study has been initiated to investigate, on gene expression level, the mechanism of IFO-induce nephrotoxicity and those whereby carnitine supplementation attenuates this serious side effect of IFO. To achieve the ultimate goals of this study, adult male rats were assigned to one of four treatment groups, namely, control, L-carnitine, IFO, and IFO plus L-carnitine. Administration of IFO for 5 days significantly increased serum creatinine, blood urea nitrogen (BUN), and total nitrate/nitrite (NOx) production in kidney tissues. In addition, IFO significantly increased mRNA expression of inducible nitric oxide synthase (iNOS), caspase-9, and caspase-3 and significantly decreased expression of glutathione peroxides (GPx), catalase (CAT), and Bcl2 in kidney tissues. Administration of L-carnitine to IFO-treated rats resulted in a complete reversal of the all biochemical and gene expression changes, induced by IFO, to the control values. Data from this study suggest that L-carnitine prevents the development of IFO-induced nephrotoxicity via downregulation of oxidative and nitrosative apoptotic signaling in kidney tissues.

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

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.

Thymoquinone supplementation attenuates cyclophosphamide-induced cardiotoxicity in rats.

This study examined the possible protective effects of thymoquinone (TQ), the main constituent of the volatile oil of black seed (Nigella sativa), against cyclophosphamide (CP)-induced cardiotoxicity. Adult male Wistar albino rats were divided into four treatment groups. Rats in the first group were served as control. Rats in the second group received TQ (50 mg/L in drinking water) for 12 days. Animals in the third group were injected with a single dose of CP (200 mg/kg, IP) at day 5. Rats in the fourth group received TQ (50 mg/L in drinking water) for 5 days before a single dose of CP (200 mg/kg, IP) and continued thereafter throughout the experiment. On day 13, animals were sacrificed; serum and hearts were isolated and analyzed. Cyclophosphamide resulted in a significant increase in serum creatine kinase, lactate dehydrogenase, cholesterol, triglycerides, creatinine, urea, and tumor necrosis factor-α. In heart tissues, CP resulted in a significant increase in thiobarbituric acid reactive substances and total nitrate/nitrite and a significant decrease in reduced glutathione, glutathione peroxidase, catalase, and adenosine triphosphate levels. Interestingly, TQ supplementation resulted in a complete reversal of all the biochemical changes induced by CP to their control values. Data from this study suggest that TQ supplementation attenuates CP-induced cardiotoxicity by a mechanism related, at least in part, to its ability to decrease oxidative and nitrosative stress and to preserve the activity of antioxidant enzymes as well as its ability to improve the mitochondrial function and energy production. .

Thymoquinone attenuates diethylnitrosamine induction of hepatic carcinogenesis through antioxidant signaling.

Hepatocellular carcinoma accounts for about 80-90% of all liver cancer and is the fourth most common cause of cancer mortality. Although there are many strategies for the treatment of liver cancer, chemoprevention seems to be the best strategy for lowering the incidence of this disease. Therefore, this study has been initiated to investigate whether thymoquinone (TQ), Nigella sativa derived-compound with strong antioxidant properties, supplementation could prevent initiation of hepatocarcinogenesis-induced by diethylnitrosamine (DENA), a potent initiator and hepatocarcinogen, in rats. Male Wistar albino rats were divided into four groups. Rats of Group 1 received a single intraperitoneal (i.p.) injection of normal saline. Animals in Group 2 were given TQ (4 mg/kg/day) in drinking water for 7 consecutive days. Rats of Group 3 were injected with a single dose of DENA (200 mg/kg, i.p.). Animals in Group 4 were received TQ and DENA. DENA significantly increased alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin, thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite (NOx) and decreased reduced glutathione (GSH), glutathione peroxidase (GSHPx), glutathione-s-transferase (GST) and catalase (CAT) activity in liver tissues. Moreover, DENA decreased gene expression of GSHPx, GST and CAT and caused severe histopathological lesions in liver tissue. Interestingly, TQ supplementation completely reversed the biochemical and histopathological changes induced by DENA to the control values. In conclusion, data from this study suggest that: (1) decreased mRNA expression of GSHPx, CAT and GST during DENA-induced initiation of hepatic carcinogenesis, (2) TQ supplementation prevents the development of DENA-induced initiation of liver cancer by decreasing oxidative stress and preserving both the activity and mRNA expression of antioxidant enzymes.

Ginger ingredients inhibit the development of diethylnitrosoamine induced premalignant phenotype in rat chemical hepatocarcinogenesis model.

To investigate the possible antitumor activity of ginger extract against hepatic carcinogenesis initiated by diethylnitrosoamines (DEN) and promoted by carbon tetrachloride (CCl(4) ). A total of 60 male Wistar albino rats were divided into four groups with 15 animals in each group. Rats in group 1 (control group) received a single intraperitoneal (i.p.) injection of normal saline. Animals in group 2 were given ginger (50 mg/kg/day) in drinking water for 8 weeks. Rats in group 3 (DEN group) were injected with a single dose of DEN (200 mg/kg, i.p.), 2 weeks later received a single dose of CCl(4) (2 mL/kg i.g) by gavage as 1:1 dilution in corn oil. Animals in group 4 (DEN-ginger group) received the same carcinogenesis induction protocol as in group 3 plus ginger (50 mg/kg/day) in drinking water for 2 weeks before induction of hepatocarcinogenesis and continued throughout the experimental period. DEN-initiated and CCl(4) -promoted hepatocarcinogenesis in male Wistar rats was manifested biochemically by elevation of serum hepatic tumor markers tested; α-fetoprotein and carcinoembryonic antigen. In addition, hepatocarcinogenesis was further confirmed by a significant increase in hepatic tissue growth factors; vascular endothelial growth factor, basic fibroblast growth factor, and hydroxyproline content. A marked decrease in endostatin and metallothonein were also observed. Long-term ginger extract administration 2 weeks before induction of hepatocarcinogenesis and throughout the experimental period prevented the decrease of the hepatic content of metallothionein and endostatin and the increase in the growth factors induced by the carcinogen. Moreover, ginger extract normalize serum hepatic tumor markers. Histopathological examination of liver tissue also correlated with the biochemical observations. These findings suggest a protective effect of ginger extract against premalignant stages of liver cancer in the DEN-initiated and CCl(4) -promoted hepatocarcinogenesis model in rats.

Inhibition of gene expression of heart fatty acid binding protein and organic cation/carnitine transporter in doxorubicin cardiomyopathic rat model.

This study examined whether doxorubicin therapy alters the expression of heart fatty acid binding protein (H-FABP) and organic cation/carnitine transporter (OCTN2) genes in cardiac tissues, and if so, whether these alterations contributes to doxorubicin-induced cardiotoxicity. Male Wistar albino rats were divided into six groups: group 1 rats were given daily intraperitoneal (i.p.) injections of normal saline for 10 consecutive days; groups 2, 3 and 4 rats were injected every other day with doxorubicin (3 mg/kg, i.p.), to obtain treatments with cumulative doses of 6, 12, and 18 mg/kg. Rats in the fifth group were injected with L-carnitine (200 mg/kg, i.p.) for 10 consecutive days. Animals in the sixth group received doxorubicin (18 mg/kg) and L-carnitine (200 mg/kg). Treatment with doxorubicin resulted in a significant and dose-dependent decrease in H-FABP and OCTN2 mRNA expression, total carnitine and ATP in cardiac tissues and a significant increase in cardiac enzymes. Moreover, doxorubicin treatment showed significant and dose-dependent increase in the expression of apoptotic genes namely P53 and CD95. Interestingly, carnitine supplementation restored doxorubicin-induced inhibition of gene expression of H-FABP and OCTN2, decrease in myocardial carnitine and ATP to the control values. In conclusion, data from this study suggest that: chronic doxorubicin therapy decreased the expression of H-FABP and OCTN2 mRNA expression in cardiac tissues. The progressive increase in cardiotoxicity enzymatic indices and the decrease in H-FABP and OCTN2 expression may point to the possible contribution of H-FABP and OCTN2 as a mechanism during development of doxorubicin cardiotoxicity.

Carnitine deficiency aggravates cyclophosphamide-induced cardiotoxicity in rats.

BACKGROUND: This study examined, for the first time, the involvement of carnitine deficiency in cardiotoxicity, particularly cyclophosphamide (CP)-induced cardiomyopathy, as well as effects of carnitine supplementation with propionyl-L-carnitine (PLC) on cardiotoxicity. METHODS: An animal model of carnitine deficiency was developed in rats treated with D-carnitine (DC)-mildronate (MD). Adult male Wistar albino rats were assigned to one of six treatment groups: the first three groups were injected intraperitoneally with normal saline, PLC (250 mg/kg/day), and DC (250 mg/kg/day) combined with MD (200 mg/kg/day), respectively, for 10 successive days. In groups 4-6, the same doses of normal saline, PLC and DC-MD were injected, respectively, during the 5 successive days before and after a single dose of CP (200 mg/kg). On day 6 after CP treatment, 24-hour urine was collected, then animals were sacrificed, and serum as well as hearts were isolated. RESULTS: CP caused a significant increase in serum creatine phosphokinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), urinary carnitine excretion and clearance and intramitochondrial acetyl-CoA/CoA-SH, and a significant decrease in serum free carnitine, total carnitine and adenosine triphosphate (ATP) contents in cardiac tissue. In the carnitine-depleted rats, CP induced dramatic increases in CK-MB and LDH levels, carnitine clearance and intramitochondrial acetyl-CoA/CoA-SH, as well as progressive reduction in total carnitine and ATP in cardiac tissues. Interestingly, PLC supplementation completely reversed the biochemical and histopathological changes induced by CP to the control values. CONCLUSION: (1) Carnitine deficiency is a risk factor which is involved in CP-related cardiomyopathy; (2) serum and urinary carnitine levels should be monitored and viewed as indices of CP-induced multiple organ toxicity, and (3) carnitine supplementation, using PLC, prevents the development of CP-induced cardiotoxicity.

Increased urinary losses of carnitine and decreased intramitochondrial coenzyme A in gentamicin-induced acute renal failure in rats.

BACKGROUND: This study examined whether carnitine deficiency is a risk factor and should be viewed as a mechanism during the development of gentamicin (GM)-induced ARF as well as exploring if carnitine supplementation could offer protection against this toxicity. METHODS: Adult male Wistar albino rats were assigned to one of six treatment groups: group 1 (control) rats were given daily intraperitoneal (I.P.) injections of normal saline for 8 consecutive days; groups 2, 3 and 4 rats were given GM (80 mg/kg/day, I.P.), l-carnitine (200 mg/kg/day, I.P.) and d-carnitine (250 mg/kg/day, I.P.), respectively, for 8 consecutive days. Rats of group 5 (GM plus d-carnitine) received a daily I.P. injection of d-carnitine (250 mg/kg/day) 1 h before GM (80 mg/kg/day) for 8 consecutive days. Rats of group 6 (GM plus l-carnitine) received a daily I.P. injection of l-carnitine (200 mg/kg/day) 1 h before GM (80 mg/kg/day) for 8 consecutive days. RESULTS: GM significantly increased serum creatinine, blood urea nitrogen (BUN), urinary carnitine excretion, intramitochondrial acetyl-CoA and total nitrate/nitrite (NOx) and thiobarbituric acid reactive substances (TBARS) in kidney tissues and significantly decreased total carnitine, intramitochondrial CoA-SH, ATP, ATP/ADP and reduced glutathione (GSH) in kidney tissues. In carnitine-depleted rats, GM caused a progressive increase in serum creatinine, BUN and urinary carnitine excretion and a progressive decrease in total carnitine, intamitochondrial CoA-SH and ATP. Interestingly, l-carnitine supplementation resulted in a complete reversal of the increase in serum creatinine, BUN, urinary carnitine excretion and the decrease in total carnitine, intramitochondrial CoA-SH and ATP, induced by GM, to the control values. Moreover, the histopathological examination of kidney tissues confirmed the biochemical data, where l-carnitine prevents and d-carnitine aggravates GM-induced ARF. CONCLUSIONS: (i) GM-induced nephrotoxicity leads to increased urinary losses of carnitine; (ii) carnitine deficiency is a risk factor and should be viewed as a mechanism during the development of GM-induced ARF; and (iii) carnitine supplementation ameliorates the severity of GM-induced kidney dysfunction by increasing the intramitochondrial CoA-SH/acetyl-CoA ratio and ATP production.

Progression of diethylnitrosamine-induced hepatic carcinogenesis in carnitine-depleted rats.

AIM: To investigate whether carnitine deficiency is a risk factor during the development of diethylnitrosamine (DENA)-induced hepatic carcinogenesis. METHODS: A total of 60 male Wistar albino rats were divided into six groups with 10 animals in each group. Rats in group 1 (control group) received a single intraperitoneal (i.p.) injection of normal saline. Animals in group 2 (carnitine-supplemented group) were given L-carnitine (200 mg/kg per day) in drinking water for 8 wk. Animals in group 3 (carnitine-depleted group) were given D-carnitine (200 mg/kg per day) and mildronate (200 mg/kg per day) in drinking water for 8 wk. Rats in group 4 (DENA group) were injected with a single dose of DENA (200 mg/kg, i.p.) and 2 wk later received a single dose of carbon tetrachloride (2 mL/kg) by gavage as 1:1 dilution in corn oil. Animals in group 5 (DENA-carnitine depleted group) received the same treatment as group 3 and group 4. Rats in group 6 (DENA-carnitine supplemented group) received the same treatment as group 2 and group 4. RESULTS: Administration of DENA resulted in a significant increase in alanine transaminase (ALT), gamma-glutamyl transferase (G-GT), alkaline phosphatase (ALP), total bilirubin, thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite (NOx) and a significant decrease in reduced glutathione (GSH), glutathione peroxidase (GSHPx), catalase (CAT) and total carnitine content in liver tissues. In the carnitine-depleted rat model, DENA induced a dramatic increase in serum ALT, G-GT, ALP and total bilirubin, as well as a progressive reduction in total carnitine content in liver tissues. Interestingly, L-carnitine supplementation resulted in a complete reversal of the increase in liver enzymes, TBARS and NOx, and a decrease in total carnitine, GSH, GSHPx, and CAT induced by DENA, compared with the control values. Histopathological examination of liver tissues confirmed the biochemical data, where L-carnitine prevented DENA-induced hepatic carcinogenesis while D-carnitine-mildronate aggravated DENA-induced hepatic damage. CONCLUSION: Data from this study suggest for the first time that: (1) carnitine deficiency is a risk factor and should be viewed as a mechanism in DENA-induced hepatic carcinogenesis; (2) oxidative stress plays an important role but is not the only cause of DENA-induced hepatic carcinogenesis; and (3) long-term L-carnitine supplementation prevents the development of DENA-induced liver cancer.

Propionyl-L-carnitine prevents the progression of cisplatin-induced cardiomyopathy in a carnitine-depleted rat model.

This study has been initiated to investigate whether endogenous carnitine depletion and/or carnitine deficiency is a risk factor during development of cisplatin (CDDP)-induced cardiomyopathy and if so, whether carnitine supplementation by propionyl-L-carnitine (PLC) could offer protection against this toxicity. To achieve the ultimate goal of this study, a total of 60 adult male Wistar albino rats were divided into six groups. The first three groups were injected intraperitoneally with normal saline, PLC (500 mg kg(-1)), and d-carnitine (500 mg kg(-1)) respectively, for 10 successive days. The 4th, 5th, and 6th groups were injected intraperitoneally with the same doses of normal saline, PLC and D-carnitine, respectively, for 5 successive days before and after a single dose of CDDP (7 mg kg(-1)). On day 6 after CDDP treatment, animals were sacrificed, serum as well as hearts were isolated and analyzed. CDDP resulted in a significant increase in serum creatine phosphokinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH), thiobarbituric acid reactive substances (TBARS) and total nitrate/nitrite (NO(x)) and a significant decrease in reduced glutathione (GSH), total carnitine, and adenosine triphosphate (ATP) content in cardiac tissues. In the carnitine-depleted rat model, CDDP induced dramatic increase in serum cardiomyopathy enzymatic indices, CK-MB and LDH, as well as progressive reduction in total carnitine and ATP content in cardiac tissue. Interestingly, PLC supplementation resulted in a complete reversal of the increase in cardiac enzymes, TBARS and NO(x), and the decrease in total carnitine, GSH and ATP, induced by CDDP, to the control values. Moreover, histopathological examination of cardiac tissues confirmed the biochemical data, where PLC prevents CDDP-induced cardiac degenerative changes while d-carnitine aggravated CDDP-induced cardiac tissue damage. In conclusion, data from this study suggest for the first time that carnitine deficiency and oxidative stress are risk factors and should be viewed as mechanisms during development of CDDP-related cardiomyopathy and that carnitine supplementation, using PLC, prevents the progression of CDDP-induced cardiotoxicity.

Modification by L-NAME of codeine induced analgesia: possible role of nitric oxide.

Objectives were to investigate the effect of nonselective nitric oxide synthase (NOS) inhibitor, L-NAME on codeine-induced analgesia and to see the role of NO in its antinociceptive effect. Also, to see if L-NAME can potentiate the antinociceptive response of sub-effective dose of codeine and to explore if opioid receptors have some role to play in L-NAME effects. Mice were injected with selected doses of codeine or other selected agents intraperitoneally and the latency to hot plate was recorded at zero, 15, 30, and 60 min of the treatments. The antinociceptive response of codeine (10 mg/kg, i.p.) was studied in comparison to those of the NOS inhibitor, L-NAME, and of nitric oxide donor, sodium nitroprusside (SNP). Assessment of nitrates and nitrites (NOx) in the sera of treated mice were also made. Codeine (20 mg/kg dose), induced analgesia significantly and dose dependently only after 15 min. L-NAME at 20, 40, and 80 mg/kg dose levels significantly changed the nonanalgesic effect of codeine (10 mg/kg) to highly significant analgesia. The effect of L-NAME 40 mg/kg was significantly higher than the other two doses and was almost equal to that of the higher dose of codeine. Naloxone itself did not show any intrinsic effect but almost abolished the L-NAME-codeine induced analgesia. Similarly, SNP (1 mg/kg) reversed the decrease in reaction time by L-NAME-codeine to its control values, significantly. Pretreatment with L-NAME rendered the nonanalgesic dose of codeine significantly analgesic almost in an equal potency to the high dose of codeine alone and indicate that the NO modulatory effect on the opioid analgesic codeine is probably, at least in part, through opioid receptors.

Protective effects of oral arabic gum administration on gentamicin-induced nephrotoxicity in rats.

Arabic gum (AG) is a complex polysaccharide used as suspending agent. It has been widely used by eastern folk medicine practitioners as a restorative agent and is thought to be an excellent curative for renal failure patients. We therefore tested these folkloric claims using a rat model of gentamicin (GM)-induced nephrotoxicity. AG (7.5g 100ml(-1), in drinking water) was administered orally for 8 days concurrently with GM (80mgkg(-1) per day, i.p.). Estimation of urine volume, serum creatinine and urea concentrations, kidney tissue malondialdehyde (MDA) contents and glutathione (GSH) were carried out after the last dose of GM. Kidneys were also examined for histological changes. GM caused a marked nephrotoxicity as evidenced by significant increases in urine volume (295%), serum creatinine (318%) and urea (258%) and a significant decrease in creatinine clearance (Ccr) (26%). Treatment with AG protected the rats from GM-induced nephrotoxicity as evident by normalisation of these parameters. In addition there was about 187% increase in kidney tissue MDA contents above the control with GM treatment. AG totally prevented the GM-induced rise in kidney tissue contents of MDA. Kidney histology of the tissue from GM-treated rats showed necrosis and desquamation of tubular epithelial cells in renal cortex as well as interstitial nephritis. Whereas it was very much comparable to control when AG was co-administered with GM. In conclusion, AG protected the rats from GM-induced nephrotoxicity, possibly, at least in part through inhibition of the production of oxygen free radicals that cause lipid peroxidation.

Effects of L-carnitine and ginkgo biloba extract (EG b 761) in experimental bleomycin-induced lung fibrosis.

The effects of Ginkgo biloba extract (EGb 761) and L-carnitine on bleomycin (BLM)-induced lung fibrosis were studied in rats. BLM (cumulative dose of 180 mgkg(-1)) was given intraperitoneally (i.p.) three times weekly for 4 consecutive weeks. Treatment with BLM enhanced the responsiveness of isolated pulmonary arterial rings to serotonin (5-HT), significantly increased the normal serum level of tumour necrosis factor (TNF-alpha) by approximately 105% and markedly elevated the level of lipid peroxide (LPO) and collagen content in the lung homogenates by 34 and 83%, respectively. EGb 761 (100 mgkg(-1) ), given in drinking water for the whole study period, totally abolished the BLM-induced alterations in the measured biochemical and pharmacological parameters. Meanwhile, L-carnitine (500 mg kg(-1) ), administered in drinking water, significantly decreased the BLM-induced elevations of serum TNF-alpha, LPO level in lung tissues and the enhanced responsiveness of pulmonary arterial rings to 5-HT. However,L-carnitine did not reduce the increase in the collagen content produced by BLM. The results of the present study indicate the beneficial effects of EGb 761 and L-carnitine against lung toxicity induced by BLM treatment. Furthermore, the present data shows the advantageous use of EGb 761 as a protective agent in BLM-induced lung fibrosis under the experimental circumstances.