animals and experimental protocol : in this investigation , 28 healthy adult 
 male wistar rats ( 13 weeks old weighing between 224252 g ) were used . the animals were 
 obtained from the adnan menderes university , faculty of veterinary medicine , experimental 
 research centre , aydn , turkey . they were suspended in screen - bottomed stainless steel cages 
 at 2224c in a room with a 12/12 hr light / dark cycle . all animals received human care 
 according to criteria outlined in the  guide for the care and use of laboratory animals  
 prepared by the national academy of sciences and published by the national institutes of 
 health . rats were randomly divided into four groups ( n=7 rats per group ) , the control , 
 contrast media ( cm ) , carnitine and contrast media+carnitine ( cm+carnitine ) groups . the rats 
 received a commercial rodent diet and had free access to tap water . after 10 days of 
 acclimatization , rats were weighed . on the 1st day of the experiment , the animals were kept in 
 individual metabolic cages on the 1st for a 1-day period . weighing of rats and sampling of 
 blood were performed between 08:00 and 09:00 a.m. to minimize circadian variation . on the 
 2nd day , rats were fed ad libitum with a standard rodent diet and were 
 deprived of water for 24 hr . on the 4th day , they were kept in individual 
 metabolic cages for a 1-day period . animals were sacrificed after 
 thiopental injection , and the right kidneys were immediately removed for histopathologic 
 evaluation . the left kidney , liver , heart , spleen and lung tissues were dissected for 
 measuring the sod and cat activities as well as the gsh and mda levels . the carnitine group received l - carnitine 500 mg / kg ( carnitene 1 g/5 ml 
 injectable ampoule , sigma - tau pharmaceuticals , gaithersburg , md , u.s.a . ) by intraperitoneal 
 ( ip ) injection on the 2nd , 3rd and 4th days of the experiment . the dose of l - carnitine 
 administered was selected according to previous reports [ 1 , 49 , 53 ] . contrast nephropathy was induced by a single dose of iohexol 10 
 ml / kg ( omnipaque 300 mg i / ml , ge healthcare , ireland ) by 
 intravenous ( iv ) injection within 5 min into the tail vein only on the 3rd day of the 
 experiment in the cm group . control animals received 0.9% nacl solution ( ip ) in the same 
 volumes as those applied for carnitine - treated rats on the 2nd , 3rd and 4th days of the 
 experiment . the cm+carnitine group received iohexol 10 ml / kg by iv 
 injection and l - carnitine 500 mg / kg by ip injection on the specified days . sample collection and analysis : both blood and urine samples were 
 collected into tubes immediately . the concentration of creatinine in serum was measured by 
 the colorimetric method ( architect c8000 , abbott , laboratories , abbott park , il , u.s.a . ) . cin was defined as an increase of 0.5 mg / dl or increase of 25% or more in 
 serum creatinine over baseline . determination of sod and cat activities and gsh and mda levels in tissues : 
 dissected kidney , liver , heart , spleen and lung tissues were immediately rinsed in ice - cold 
 phosphate - buffered saline . tissues were homogenized ( 2,000 rpm / min for 1 min , 1/10 w / v ) 
 using a stirrer ( ika overhead stirrer ; ika - werke gmbh & co. kg , staufen , germany ) in 10% 
 150 mm phosphate buffer ( ph 7.4 ) in an ice bath . the homogenate was centrifuged ( nve - bench 
 top centrifuge , nf 800r , nve , ankara , turkey ) at 6,000 g for 10 min at 
 4c . the supernatants were frozen at 80c ( glacier ultralow temperature freezer , japan ) in 
 aliquots until analyzed . in supernatants , total protein levels were determined by a spectrophotometer ( shimadzu 
 uv-1601 , kyoto , japan ) using commercially available kits ( archem diagnostic ind . ltd . , 
 istanbul , turkey ) . the tissue homogenate was used for lipid peroxidation estimation , which was performed by 
 measuring the formation of thiobarbituric acid reactive substances ( tbars ) according to the 
 method of yoshioka et al . . the concentration of mda was 
 calculated by the absorbance coefficient of the mda - tba complex ( absorbance coefficient 
 =1.56  10/m / cm ) and expressed as nmol / mg tissue protein . the activity of cat was measured by following the rate of h2o2 
 decomposition at 240 nm . tissue supernatant was deproteinized in glacial metaphosphoric acid / di - na 
 edta / nacl ( in 100 ml distilled water , 1.67 , 0.2 and 30.0 g , respectively ) . 
 afterwards , 0.5 ml of the supernatant or standard with 0.25 
 ml of 1 mol / l sodium phosphate buffer ( ph 6.8 ) and 0.5 
 ml of 55-dithiobis ( 2-nitrobenzoic acid ) ( dntb 0.8 g / l 
 in phosphate buffer ) was left to stand for 5 min . the results were determined by comparison with an aqueous standard solution of 
 gsh ( sigma chemical co. , st . louis , mo , u.s.a . ) and expressed as mg / g tissue protein . sod estimation 
 was based on the generation of superoxide radicals produced by xanthine on xanthine oxidase , 
 which reacts with 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride to form a 
 red formazan dye . the absorbance was measured at 560 nm by a 
 spectrophotometer , and the results are shown as u / mg tissue protein . renal histopathological investigation : for histopathological analysis , the 
 right kidney tissues were fixed in 10% neutral buffered formalin and embedded in paraffin . samples were cut into sections 4-m thick and stained with 
 hematoxylin - eosin ( h&e ) and then examined under a microscope . two to 6 longitudinally 
 and transversally cut sections from each animal were used for microscopic evaluation . the histopathological 
 evaluation of the glomeruli , tubules , interstitium and arteries of the kidney was performed 
 by using a 4-point scale : 0=normal ( 05% involvement ) , 1=mild ( 525% involvement ) , 
 2=moderate ( 2575% involvement ) and 3=severe ( 75100% involvement ) . statistical analysis : data for biochemical parameters , tissues weights and 
 the histopathological evaluation were checked for normal distribution with the shapiro - wilk 
 test and for homogeneity of variance with levene s test . the data were compared among groups 
 using kruskal - wallis analysis of variance ( anova ) or one - way anova according to whether data 
 were normally distributed or not . post hoc multiple comparisons were performed using the 
 mann - whitney u test with bonferroni corrected or duncan s test . serum creatinine , creatinine 
 clearance and body weight were compared with a paired sample t - test . all 
 analyses were performed using the statistical package for the social sciences ( spss ) 
 software . serum creatinine and creatinine clearance : serum creatinine and the 
 creatinine clearence levels of the control and carnitine groups were not significantly 
 changed on the 5th day , whereas serum creatinine increased and creatinine clearance levels 
 decreased ( p<0.05 ) in the cm group . furthermore , serum creatinine levels 
 decreased in the cm+carnitine group ( p<0.05 ) significantly . serum 
 creatinine and creatinine clearance levels of each group are shown in table 1table 1.serum creatinine and creatinine clearance levels of each group on the 1st day and 
 5th day ( n=7)parametersserum creatinine ( mg / dl ) # creatinine clearance ( ml / min)days1st5thp1st5thpcontrol0.40 ( 0.400.60)0.40 ( 0.400.50)ns1.32  0.381.16  0.34nscm0.50 ( 0.400.50)0.60 ( 0.500.80)*1.20  0.140.85  0.33*carnitine0.50 ( 0.500.70)0.50 ( 0.400.50)ns1.15  0.370.99  0.36nscm+carnitine0.50 ( 0.500.60)0.40 ( 0.400.40)*0.87  0.221.07  0.20ns * p<0.05 ; ns , not significant ; cm , contrast medium ; 
 cm  +  carnitine , contrast medium  +  carnitine treatment . # serum creatinine parameters 
 are expressed as medians ( interquartile range ) .. * p<0.05 ; ns , not significant ; cm , contrast medium ; 
 cm  +  carnitine , contrast medium  +  carnitine treatment . body and tissues weights : in all groups , body weights were significantly 
 lower ( p<0.05 ) on day 3 after the dehydration phase ( table 2table 2.body weight ( g ) changes in each group ( n=7)groupsbody weight ( g)p1st day3rd daycontrol230.00  11.38210.29  11.11*cm239.43  14.70217.86  12.90*carnitine224.14  9.24211.71  6.80*cm+carnitine252.86  7.79224.86  7.04 * * p<0.05 ; cm , contrast medium ; cm  +  carnitine , contrast 
 medium  +  carnitine treatment . ) . at the end of the experiment , tissues weights , except for those of the 
 kidney , did not differ significantly among treatments ( table 3table 3.tissues weight ( g ) in each group ( n=7)tissuesgroupspcontrolcmcarnitinecm+carnitinekidney0.89  0.040.91  0.030.90  0.051.07  0.03*liver7.53  0.408.81  0.537.33  0.357.95  0.34nsheart0.75  0.020.77  0.020.71  0.020.79  0.03nsspleen0.66  0.040.73  0.030.67  0.070.68  0.06nslung1.41  0.041.59  0.121.52  0.091.56  0.07nsa , b ) different letters indicate statistically significant differences in the same 
 row . * p<0.05 ; ns , not significant ; cm , contrast medium ; 
 cm+carnitine , contrast medium+carnitine treatment . ) . only the kidney weight was significantly different among treatments . when 
 compared with other groups , * p<0.05 ; cm , contrast medium ; cm  +  carnitine , contrast 
 medium  +  carnitine treatment . a , b ) different letters indicate statistically significant differences in the same 
 row . * p<0.05 ; ns , not significant ; cm , contrast medium ; 
 cm+carnitine , contrast medium+carnitine treatment . sod and cat activities and gsh and mda levels in tissues : the sod and cat 
 activities and gsh and mda levels of renal , liver , heart , spleen and lung tissues in rats 
 with contrast - induced nephropathy are given in table 
 4table 4.the sod and cat activities and the gsh and mda levels in renal , liver , heart , 
 spleen and lung tissues of rats with contrast - induced nephropathy ( n=7)tissue / parametersexperimental groupspcontrolcmcarnitinecm + carnitinerenalsod , u / mg protein2.90  0.212.30  0.203.53  0.463.16  0.12*cat , k / mg protein0.66  0.320.43  0.201.03  0.520.71  0.24nsgsh , mg / g protein0.38  0.020.29  0.020.40  0.020.38  0.03*mda , nmol / mg protein222.01  19.77569.54  37.56351.80  40.18426.69  52.86***liversod , u / mg protein5.49  0.393.75  0.347.22  0.853.93  0.22***cat , k / mg protein27.30  8.3317.91  3.3428.70  5.5921.66  2.19nsgsh , mg / g protein1.00 0.140.38  0.051.40  0.220.70  0.12***mda , nmol / mg protein165.35  11.36223.92  22.08109.41  10.67110.78  8.17***heartsod , u / mg protein4.12  0.912.49  0.544.39  0.653.71  0.37nscat , k / mg protein1.16  0.740.37  0.081.16  0.741.03  0.42nsgsh , mg / g protein0.47 0.080.29  0.050.46  0.110.42  0.10nsmda , nmol / mg protein111.04  17.87136.73  38.5690.75  11.4291.11  8.34nsspleensod , u / mg protein4.07  0.662.15  0.433.65  0.183.27  0.20*cat , k / mg protein1.39  0.300.42  0.061.19 0.141.35  0.15**gsh , mg / g protein0.64  0.130.27  0.021.02  0.100.73  0.08***mda , nmol / mg protein54.07  6.1361.82  4.0621.78 1.9352.90  3.90***lungsod , u / mg protein1.31  0.131.05  0.071.16  0.061.12  0.03nscat , k / mg protein0.41  0.110.32  0.140.51  0.150.46  0.09nsgsh , mg / g protein0.45  0.030.30  0.040.50  0.030.43  0.04**mda , nmol / mg protein25.79  1.0530.16  0.5324.13  0.7127.14  0.95***a , b , c ) different letters indicate statistically significant differences in the same 
 row . * ns , not significant ; cm , contrast medium ; cm+carnitine , 
 contrast medium+carnitine treatment ; sod , superoxide dismutase activity ; cat , 
 catalase ; gsh , glutathione ; mda , malondialdehyde .. a , b , c ) different letters indicate statistically significant differences in the same 
 row . * ns , not significant ; cm , contrast medium ; cm+carnitine , 
 contrast medium+carnitine treatment ; sod , superoxide dismutase activity ; cat , 
 catalase ; gsh , glutathione ; mda , malondialdehyde . mda levels in renal tissue were increased in the cm group ( p<0.001 ) . 
 when compared with the cm group , gsh levels were significantly higher in the cm+carnitine 
 group ( p<0.05 ) . compared with the cm group , the sod activities of the 
 control and cm+carnitine groups were increased ( p>0.05 ) . the sod 
 activity and gsh level in liver tissue were increased , whereas the mda level was decreased 
 in the carnitine group significantly ( p<0.001 ) . when compared with the 
 cm group , the sod activity and gsh level of the cm+carnitine group were higher in liver 
 tissue , but these results did no differ significantly ( p>0.05 ) . on the 
 other hand , compared with the cm group , the mda level of the cm+carnitine group was 
 decreased in liver tissue significantly ( p<0.001 ) . there was no 
 difference found in the mean sod and cat activities and gsh and mda levels among treatments 
 in heart tissue ( p>0.05 ) . the mda level in spleen tissue was increased 
 in the control , cm and cm+carnitine groups ( p<0.001 ) . compared with the 
 other groups , the sod ( except for the cm+carnitine group ) and cat activities and gsh levels 
 in the cm group were decreased significantly ( p<0.05 , 
 p<0.01 and p<0.001 , respectively ) . when compared 
 with the cm group , the sod and cat activities in lung tissue of the carnitine and 
 cm+carnitine groups were higher , but these findings were not significant 
 ( p>0.05 ) . in the cm group , the gsh level decreased 
 ( p<0.01 ) , and the mda level increased ( p<0.001 ) 
 significantly in lung tissue . we investigated whether the oxidative stress parameters of the experimental groups were 
 statistically significant or not among the tissues ( fig . 1.the sod and cat activities and gsh and mda levels in renal , liver , heart , spleen and 
 lung tissues of experimental groups . * 
 p<0.05 ; * * p<0.01 ; * * * 
 p<0.001 . ) . in the cm and carnitine groups , the liver tissue had significantly higher sod 
 activities compared with the other tissues ( p<0.001 and 
 p<0.001 respectively ) . cat activities were quite higher in liver 
 tissues when compared with all other experimental groups ( p<0.001 ) . the 
 gsh levels in the cm group were not significant between the tissues 
 ( p>0.05 ) , but they were statistically higher in liver and spleen tissues 
 in the carnitine group ( p<0.05 ) . mda levels were higher in renal tissues 
 in all experimental groups ( p<0.001 ) . the sod and cat activities and gsh and mda levels in renal , liver , heart , spleen and 
 lung tissues of experimental groups . ns , not significant . * 
 p<0.05 ; * * p<0.01 ; * * * 
 p<0.001 . renal histopathological evaluation : renal histopathological examination of 
 the control group showed mild dilatation in the renal tubules . interstitial fibrosis was not 
 observed in the experimental groups , whereas glomerular sclerosis was seen in the carnitine 
 group . image of mild dilatation ( arrows ) in the renal tubules of the control group 
 ( h&e ,  200 ) . b. image of mild tubular dilation ( arrow ) and tubular degeneration 
 ( small arrowheads ) together with glomerular sclerosis ( arrowhead ) in renal tissue of 
 the carnitine group ( h&e ,  200 ) . c. image of focal glomerular necrosis ( long 
 arrows ) , degeneration and dilatation in the tubular epithelium ( small arrows ) , 
 expansion of bowman s capsule ( arrowhead ) , inflammation ( asterisks ) and thickening of 
 the blood vessel wall ( white arrow ) in renal tissue of the cm group ( h&e ,  200 ) . d. image of congestion ( long arrow ) and mild dilatation in the 
 tubular epithelium ( small arrows ) in renal tissue of the cm+carnitine group ( h&e , 
  400 ) . focal glomerular necrosis , expansion of bowman s capsule , degeneration in the tubule 
 epithelium , necrosis of the tubular epithelium , dilatation of tubules , interstitial 
 infiltration , vascular congestion and thickening of blood vessel wall scores were higher in 
 the cm group than in the other groups . the presence of focal glomerular 
 necrosis , expansion of bowman s capsule , degeneration in the tubule epithelium , 
 necrosis of the tubular epithelium , dilatation of tubules , interstitial infiltration , 
 vascular congestion and thickening of the blood vessel wall is indicated for each 
 group . cm , contrast medium ; cm+carnitine , contrast medium+carnitine treatment . a , 
 b different letters indicate statistically significant differences in the 
 experimental groups . ns , not significant . * p<0.05 ; 
 * * p<0.01 ; * * * p<0.001 . a. image of mild dilatation ( arrows ) in the renal tubules of the control group 
 ( h&e ,  200 ) . b. image of mild tubular dilation ( arrow ) and tubular degeneration 
 ( small arrowheads ) together with glomerular sclerosis ( arrowhead ) in renal tissue of 
 the carnitine group ( h&e ,  200 ) . c. image of focal glomerular necrosis ( long 
 arrows ) , degeneration and dilatation in the tubular epithelium ( small arrows ) , 
 expansion of bowman s capsule ( arrowhead ) , inflammation ( asterisks ) and thickening of 
 the blood vessel wall ( white arrow ) in renal tissue of the cm group ( h&e ,  200 ) . d. image of congestion ( long arrow ) and mild dilatation in the 
 tubular epithelium ( small arrows ) in renal tissue of the cm+carnitine group ( h&e , 
  400 ) . the presence of focal glomerular 
 necrosis , expansion of bowman s capsule , degeneration in the tubule epithelium , 
 necrosis of the tubular epithelium , dilatation of tubules , interstitial infiltration , 
 vascular congestion and thickening of the blood vessel wall is indicated for each 
 group . cm , contrast medium ; cm+carnitine , contrast medium+carnitine treatment . a , 
 b different letters indicate statistically significant differences in the 
 experimental groups . ns , not significant . * p<0.05 ; 
 * * p<0.01 ; * * * p<0.001 . there was no significant histopathological change observed by thickening of the blood 
 vessel wall in the renal tissue of any group ( p>0.05 ) . when compared 
 with other groups , focal glomerular necrosis , expansion of bowman s capsule , degeneration in 
 the tubule epithelium , necrosis of the tubular epithelium ( p<0.001 ) , 
 dilatation of tubules ( p<0.05 ) , interstitial infiltration 
 ( p<0.01 ) and vascular congestion ( p<0.01 ) were 
 increased significantly in the cm group . the direct toxic effects of iodinated contrast agents in conjunction with changes 
 in renal hemodynamics allow for the renal damage . infusion of a contrast agent increases 
 renal free radical production through postischemic oxidative stress . l - carnitine plays a 
 role as the inhibitor of free radical production processes and oxidative stress . the most 
 important finding of this study is the demonstration of a significant decrease in the 
 incidence of cin by means of l - carnitine administration in contrast media - exposed rats . in 
 addition , the effectiveness of l - carnitine for the prevention of cin was demonstrated 
 histopathologically . the present study indicated that the antioxidant properties of 
 l - carnitine might have contributed to these positive findings . on day 5 , the serum creatinine level was higher , and carnitine clearance was lower in the 
 cm group due to nephropathy . furthermore , serum creatinine levels were decreased 
 significantly in the cm+carnitine group ( p<0.05 ) , and creatinine 
 clearance of this group was increased . it was previously shown that creatinine levels were 
 increased by contrast - induced nephropathy in rat models [ 10 , 18 , 37 ] . the prominent finding of this study is the 
 demonstration of no significant difference between the control , carnitine and cm+carnitine 
 groups by means of more serious pathological findings like focal glomerular necrosis , 
 expansion of bowman s capsule , degeneration in the tubule epithelium , necrosis of the 
 tubular epithelium and interstitial infiltration . even though there was no exposure to 
 contrast media , there were mild pathological findings in renal tissue of the control group . this may be because of the effect of dehydration as well as individual stresses of the 
 rats . body weights of among groups were not significantly different on the 1st and 3rd days 
 ( p>0.05 ) . however , weight loss ( % ) occurred only in the carnitine 
 group ( p<0.01 ) . compared with the other groups , body weight in the 
 cm+carnitine group increased on the 1st and 3rd days ( p>0.05 ) . the 
 higher kidney weight may be due to body weight ( see table 2 ) . in addition , when compared with the cm group , mild pathological findings 
 were found in renal tissue of the cm+carnitine group ( see fig . 2 ) . oxidative stress causes damage of cellular proteins , cellular organelles , dna and membrane 
 lipids . it can lead to cell death and has a direct effect on the progression of cancer , 
 aging and degenerative diseases . it increases formation of superoxide radicals and hydrogen 
 peroxide , lipid peroxidation and protein oxidation , which can directly promote cellular 
 damage [ 27 , 51 ] . the antioxidant and free radical scavenger activities of l - carnitine have been 
 proposed to have several mechanisms [ 3 , 14 , 23 ] . the beneficial effects of propionyl - l - carnitine have been documented in rat models of renal 
 ischemia reperfusion injury . of interest , the mda level also increased in response to contrast medium 
 administration via oxidative stress in renal tissues of rats ( p<0.001 ) . additionally , gsh levels were decreased ( p<0.05 ) after the 
 administration of contrast media compared with the control group in renal tissues . it has 
 been suggested that improved gsh levels after l - carnitine addition in rats may also be 
 attributed to increased nicotinamide adenine dinucleotide phosphate hydrogen ( nadph ) 
 generation through increased fatty acid metabolism . sod converts superoxide to less 
 cytotoxic hydrogen peroxide , which then decomposes into water via the enzymes cat and 
 glutathione peroxidase . in this study , the gsh level was higher 
 ( p<0.05 ) , and the mda level was lower ( p<0.001 ) in 
 the cm+carnitine group as compared with the cm group ; however , the sod activity was 
 unaffected ( p>0.05 ) . the sod activity was increased in the control group 
 when compared with the cm group , but the difference was not significant 
 ( p>0.05 ) . these findings suggest oxygen radicals play an important role in this particular 
 nephrotoxicity model . all data from the present trial suggest that l - carnitine may have an 
 important role in preventing cin and that its antioxidant properties seem to play the major 
 role . it was reported previously that there was an increase in brain sod and cat activities 
  and depletion in liver gsh levels and lipid 
 peroxidation in response to an increase in tissue mda levels . the liver tissue sod activity and gsh level were higher in the 
 cm+carnitine group than in the cm group , but the differences among these treatments were not 
 significant . on the other hand , these results may be attributable to the therapeutic 
 dose of l - carnitine being insufficient to be effective in this study . when compared with the cm group , the sod and cat activities and gsh level in the 
 cm+carnitine group were higher , and the mda level was lower ( p>0.05 ) in 
 heart tissue . tbars are formed as a by - product of lipid peroxidation and are markers of 
 oxidative stress . additionally , ay 
 et al .   have shown that exposure 
 of isolated hearts to contrast agents provokes a transient but reversible contractile 
 dysfunction and limited capillary ruptures . the results of the present study are in 
 agreement with those of other researchers . these findings suggest that a contrast medium may 
 not have an effect on heart tissue . compared with other groups , the cat activity and gsh level in the cm+carnitine group 
 increased significantly ( p<0.01 and p<0.001 , 
 respectively ) in spleen tissue . the increased cat activity and gsh level may have been 
 insufficient to prevent lipid peroxidation , because the mda level decreased significantly in 
 the carnitine group only ( p<0.001 ) . l - carnitine has a protective effect on the activities of sod 
 and cat . however , when compared with other 
 tissues , cat activity was important only in spleen tissue ( p<0.01 ) . increased cat activity might have been sustained to counteract fast generating superoxide 
 radicals , or gsh may have protected the cells from reactive free radicals and peroxides . demonstrate that decreased cat activity may be due to decreased generation of nadph and 
 thereby reduce turnover of gsh from oxidized glutathione . our results showed no significant alterations in cat activity 
 ( p>0.05 ) , whereas the gsh level was significantly high in renal , liver 
 and lung tissues ( p<0.05 , p<0.001 and 
 p<0.01 , respectively ) . our results showed no significant difference in 
 lung tissue sod and cat activities ( p>0.05 ) , but the gsh level was 
 significantly higher ( p<0.01 ) and the mda level was significantly lower 
 ( p<0.001 ) in the cm+carnitine group . it was reported that sod 
 localized in the cytoplasm and in the mitochondria of cells , indicating that lipid 
 peroxidation damaged the cell membrane , leading to an increase in mda , but did not damage 
 cell components , such as mitochondria . as 
 reported earlier , the attenuation of the increase in antioxidant enzyme activities by 
 l - carnitine might be conveyed by restoring energy metabolism via enhancement of 
 mitochondrial -oxidation . the aim of this study was to investigate the prophylactic effects of l - carnitine against 
 cin in the kidney . however , oxygen free radicals caused by cin induced not only renal 
 tissues but also liver , spleen and lung tissues . l - carnitine plays an important role in balancing antioxidative systems and has an 
 antiperoxidative effect . the production of o2 , 
 h2o2 and oh is catalyzed by free iron through the 
 haber - weiss reaction . carnitine partially 
 inhibits iron - induced lipid peroxidation in liposomes by forming complexes with free iron 
 . gulcin   has shown that l - carnitine inhibition of lipid peroxidation was higher than 
 those of -tocopherol and trolox ( analog of vitamin e)in vitro . .   demonstrated that 
 levels of antioxidant enzymes ( sod , cat and gshpx ) and nonenzymatic antioxidants ( gsh , 
 vitamin c and vitamin e ) were decreased in the mitochondria of blood and skeletal muscle in 
 aged rats . additionally , supplementation with l - carnitine in aged rats improved the 
 antioxidant status . our results show that l - carnitine administration stimulated sod and cat 
 activities and gsh levels in tissues . high - osmolar contrast media ( around 2,000 mosm / kg h2o ) is suggested to be more 
 nephrotoxic than low - osmolar contrast media ( 600 to 800 mosm / kg h2o ) . however , in 
 high - risk patients , isosmolar contrast media ( iocm ) ( 290 mosm / kg h2o ) is still 
 suggested to be the first line agent , as it was demonstrated to be less nephrotoxic than 
 locm [ 7 , 17 , 
 34 ] . in our study , rats were deprived of water for 
 24 hr on the second day . on the third day our data showed that iohexol could cause renal damage , despite application of 
 l - carnitine at 500 mg / kg / day by ip injection on the 2nd , 3rd and 4th days of the experiment , 
 which suggests that the application days may have been insufficient . . it may provide protection by reducing 
 the concentration of oxidant products by scavenging free radicals and supporting the 
 antioxidant system . nevertheless , the therapeutic dose or application days of l - carnitine 
 might have been insufficient in the present study . it is possible that l - carnitine 
 prophylaxis may be useful in the prevention of cin if the therapeutic dose or application 
 days are increased . however , further research is needed to understand the possible 
 mechanisms of l - carnitine in prevention of cin .
abstractthis study was conducted to investigate the prophylactic effects of carnitine 
 against contrast - induced nephropathy ( cin ) and its relation to oxidant / antioxidant status 
 in kidney , liver , heart , spleen and lung tissues in a cin rat model . 
 twenty - eight adult 
 male wistar rats were divided into 4 groups , the control , contrast media ( cm ) , carnitine 
 and contrast media+carnitine ( cm+carnitine ) groups . 
 animals were placed in individual 
 metabolism cages , and on the 2nd day , rats were deprived of water for 24 hr . on the 3rd 
 day 
 , contrast media were administered to groups cm and cm+carnitine . 
 l - carnitine was 
 administered on days 2 , 3 and 4 . 
 histopathological changes were evaluated in the right 
 kidney after euthanization . 
 superoxide dismutase ( sod ) and catalase ( cat ) activities and 
 glutathione ( gsh ) and malondialdehyde ( mda ) levels were measured in renal , liver , heart , 
 spleen and lung tissues . 
 the sod activities in the renal ( p<0.05 ) , 
 liver ( p<0.001 ) and spleen ( p<0.05 ) tissues were 
 increased in the carnitine group . 
 the cat activities in the spleen tissue were decreased 
 ( p<0.01 ) only in the cm group . 
 renal ( p<0.05 ) , 
 liver ( p<0.001 ) , spleen ( p<0.001 ) and lung tissue 
 ( p<0.01 ) gsh levels were found to be higher in the carnitine group . 
 in renal , liver and lung 
 tissues , the mda levels increased in the cm group 
 ( p<0.001 ) . 
 the histopathological findings showed that l - carnitine 
 may have a preventative effect in alleviating the negative effects of cin . 
 similar to 
 this , l - carnitine may play a major role in the stability of the antioxidant status in the 
 kidney , liver , spleen and lung of the cin rat model .