ABSTRACT
BACKGROUND: Acute-phase proteins (APPs) may be increased due to different stresses during estrus phase in farm animals. AIMS: Determining changes of APPs at different phases of non-synchronized estrous cycle group (NSEG), and Ovsynch-synchronized estrous cycle group (SEG) in Holstein cows. METHODS: Twelve non-pregnant clinically and paraclinicaly healthy Holstein cows with a body condition score (BCS) of 2.75 and 70 days in milk were chosen. Two groups including NSEG and SEG were performed. Blood sampling was carried out from NSEG at the time of diestrus, proestrus, and estrus. In SEG, blood sampling was performed on day 7 (at the time of prostaglandin injection, equivalent diestrus), day 9 (at the time of gonadotropin-releasing hormone (GnRH) injection, equivalent proestrus), and day 10 (at the time of insemination, equivalent estrus) of synchronization protocol. Concentrations of haptoglobin (Hp), serum amyloid A (SAA), ceruloplasmin (Cp), and fibrinogen (Fib) were measured. RESULTS: Concentration of Hp at estrus phase was significantly higher compared with diestrus (P=0.001) and proestrus (P=0.019) in NSEG. Moreover, Hp level in the NSEG was significantly higher than SEG at estrus phase (P=0.002). Concentrations of SAA, Cp, and Fib had no significant differences during various phases of estrous cycle in each group or between equivalent phases of both groups. CONCLUSION: It seems that unlike SAA, Fib, and Cp, concentrations of Hp may be affected by different phases of estrous cycle. Although APPs are not specific indicators, their changes besides other clinical and paraclinical indices may be helpful for more accurate heat detection in dairy cows.
ABSTRACT
Doxorubicin (DOX) is one of the secondary metabolites of Streptomyces peucetius var. caesius. It is a common and effective chemotherapeutic agent used for the treatment of different diseases, including lymphoma, leukemia, breast cancer, and solid tumors. However, this medicine causes cardiotoxic side effects, which limit its clinical application. The present study examined the cardiomyopathy induced by DOX via echocardiography and transmission electron microscopy (TEM). The main objective was to evaluate the capacity of echocardiography and TEM as diagnostic tools for DOX-induced cardiotoxicity. Moreover, the correlation between intracellular and functional changes due to cardiotoxicity was assessed in a rat model. Cardiomyopathy was induced in rats by two cumulative doses of DOX. Group I received DOX 12 [i.e., 12 mg/kg, intraperitoneal (IP)] and group II received DOX 15 (i.e., 15 mg/kg, IP) in six equal doses over two weeks. Group III as the control (Ctrl) group received normal saline as a vehicle. Mortality during the study was only observed in the DOX 15 group. The echocardiographic assessments revealed significant changes in ejection fraction, fractional shortening, and heart rate in the groups which received DOX. In addition, severe cardiac arrhythmia was evident in DOX-treated groups. Remarkable adverse effects, such as moderately degenerated cells and inflated mitochondria were observed in the TEM analysis of rat hearts in the DOX groups. The present study indicated that rat models are suitable for investigating DOX-induced cardiomyopathy, especially at the dose of 12 mg/kg. Furthermore, echocardiography and TEM examinations were found to be valuable methods for the determination of cardiotoxicity in rats due to DOX.
Subject(s)
Antibiotics, Antineoplastic , Doxorubicin , Echocardiography , Heart , Myocardium , Animals , Male , Rats , Antibiotics, Antineoplastic/toxicity , Cardiotoxicity , Doxorubicin/toxicity , Heart/drug effects , Microscopy, Electron, Transmission , Myocardium/pathology , Myocardium/ultrastructure , Random Allocation , Rats, WistarABSTRACT
Antioxidant compounds inhibit formation of free radicals, chelate catalytic metals, and scavenge free radicals in biological systems. In addition, antioxidants play a decisive role in prevention of numerous physiological dysfunctions, cancers, and metabolic disorders. This study sought to evaluate the antioxidant capacity and cytotoxic effect of grape seed extract (GSE), crocin (CRO), and phenytoin (PHEN) on a human breast cancer cell line (MCF-7). Methanol extracts of the three mentioned agents were prepared and their antioxidant activity was evaluated by diphenyl-1-picrylhydrazyl method, using Quercetine (QUER) as positive control. The 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxic effect of the extracts on Michigan Cancer Foundation-7MCF-7 cell line, using doxorubicin hydrochloride (DOX) as the positive control. Given the results, greater scavenging activity was achieved by using GSE in comparison to CRO and PHEN. Further, a significant correlation was found between the antioxidant activity and cytotoxic effects of these agents, and GSE had the highest antioxidant capacity and cytotoxic effect in comparison to CRO and PHEN.
Subject(s)
Carotenoids/pharmacology , Free Radical Scavengers/pharmacology , Grape Seed Extract/pharmacology , Phenytoin/pharmacology , Carotenoids/toxicity , Free Radical Scavengers/toxicity , Grape Seed Extract/toxicity , Humans , MCF-7 Cells , Phenytoin/toxicity , Tetrazolium Salts/chemistry , Thiazoles/chemistryABSTRACT
BACKGROUND AND PURPOSE: Fusariosis is a fungal infection often involving the skin. Various species can cause local, focally invasive, or disseminated infections. The routes of entry for Fusarium species include the respiratory tract, gastrointestinal tract, toe nails, trauma to the skin, and indwelling central venous catheter. CASE REPORT: Herein, we present the case of a 35-year-old woman presenting with interdigital intertrigo. The patient had no predisposing factors and she did not take any antifungal agents. Fusiform macroconidia were observed on the slide culture of the fungus. The etiological agent of the infection was identified as Fusarium oxysporum through sequencing of the translation elongation factor-1 alpha (TEF-1α) gene using the primers EF1 and EF2. CONCLUSION: Fusariosis commonly presents as a severe fungal infection in immunocompromised patients. However, this infection may also occur in immunocompetent patients. Although treatment with amphotericin B is a routine antifungal therapy for fusariosis, many azoles such as cloterimazole can be used topically with fewer side-effects.
ABSTRACT
This study was set to investigate whether the adverse effects of long-term copper (Cu) consumption on testicular tissue could be prevented by zinc (Zn) administration. Forty-five mature male mice were randomly divided into one control and two treatment groups. The first treatment group received copper sulphate (Cu experimental group). The second treatment group was given combined treatment of copper sulphate and zinc sulphate (ZC experimental group). Control animals received normal saline using the same volume. Five mice from each group were sacrificed on day 14, 28 and 56 from the beginning of treatments. Left testes were removed for histopathological and histomorphometrical evaluations. Morphometrically, the diameter of seminiferous tubules and Sertoli cell nuclei, epithelial height, meiotic index and the percentage of spermatogenesis in Cu groups showed significant decrease compared to those of the control groups (P < 0.05). A partial improvement was seen in the percentage of spermatogenesis and meiotic index (P < 0.05) in ZC groups, whereas a complete recovery was observed in the rest of parameters in ZC group after 56 days compared to the control group (P > 0.05). Results showed that long-term administration of Cu leads to histological impairments of testis and zinc supplementation might offset these damaging effects.
Subject(s)
Copper Sulfate/adverse effects , Zinc Sulfate/therapeutic use , Animals , Male , Mice , Organ Size , Seminiferous Tubules/drug effects , Sertoli Cells/drug effects , Spermatogenesis/drug effects , Testis/pathologyABSTRACT
This study investigated the role of vitamin C as an antioxidant in protecting the testis against damage in experimental unilateral cryptorchidism. Forty-five male Wistar Albino rats were divided into three groups. The control group had intact rats, the cryptorchid group had unilateral cryptorchid rats and the treatment group had unilateral cryptorchid rats that it received vitamin C at a dose of 50 mg kg(-1) body weight intraperitoneal, once a day, during experimental period. Histopathological samples were obtained from five cases of 15 animals of each group at 15, 30 and 60 days after induction of cryptorchidism. The results showed histopathological parameters of the cryptorchid (left) testes in the cryptorchid group significantly decreased compared with the control group (P < 0.05), and treatment with vitamin C after 60 days significantly improved all parameters of these testes compared with the cryptorchid group (P < 0.05). In addition, the left testes on unilateral cryptorchid rats had noticeable adverse effects on the scrotal (right) testes (P < 0.05). Treatment with vitamin C after 60 days significantly improved all parameters of these testes compared with the cryptorchid group (P < 0.05). It can be concluded that treatment with vitamin C significantly improved histopathological parameters in scrotal testes on unilateral cryptorchid rats.
Subject(s)
Ascorbic Acid/pharmacology , Cryptorchidism/prevention & control , Testis/drug effects , Animals , Cryptorchidism/pathology , Male , Meiosis , Rats , Spermatogenesis , Testis/pathology , Testis/physiopathologyABSTRACT
Amodiaquine is an antimalarial drug used in the prophylaxis and treatment of this disease. However, hepatotoxicity as a life-threatening adverse effect is associated with its clinical use. We evaluated amodiaquine-induced toxicity in isolated rat hepatocytes as an in vitro model for studying drug-induced hepatotoxicity. This study attempts to investigate the protective effects of taurine and N-acetyl cysteine against the cytotoxicity induced by amodiaquine. Hepatocytes were prepared by the method of collagenase enzyme perfusion via portal vein. This technique is based on liver perfusion with collagenase after removal of calcium ion (Ca(2+)) with a chelator (ethylene glycol tetraacetic acid (EGTA) 0.5 mM). Cells were treated with different concentrations of amodiaquine, taurine and N-acetyl cysteine. Cell death, protein carbonylation, reactive oxygen species formation, lipid peroxidation, and mitochondrial depolarization were assessed as toxicity markers. Amodiaquine cytotoxic mechanism involved protein carbonylation as well as reactive oxygen species formation and lipid peroxidation. In addition, mitochondria seem to be a target for amodiaquine to induce cellular damage. Administration of taurine (200 µM) and/or N-acetyl cysteine (200 µM) reduced oxidative stress, lipid peroxidation and protein carbonylation caused by amodiaquine. Furthermore, amodiaquine-induced mitochondrial injury was significantly mitigated by taurine and/or N-acetyl cysteine. In glutathione-depleted cells, only N-acetyl cysteine protected hepatocytes against amodiaquine, and taurine showed no protective properties in this situation. Taurine and N-acetyl cysteine protect hepatocytes against amodiaquine probably via their antioxidant properties and counteracting oxidative stress.
ABSTRACT
We evaluated the effect of Creatine (Cr) supplementation on muscle fatigue and physiological indices after intermittent swimming bouts in trained swimmers. Sixteen healthy non-elite swimmers (19±4 years, 75±12 kg) were randomly assigned into two groups of either Cr supplementation or placebo and performed six repeated sprints swimming bouts of 50-m departing every 120 seconds. The Cr group was supplemented 4 times a day for 6 days. Blood lactate, Creatine Kinase (CK), creatinine, heart rate, best repeated sprint (RSb) and mean repeated sprint (RSm) times, and percentage of speed decrement (%Dec) were measured at the various phases of swimming bouts. Repeated measure ANOVA and independent t-student tests showed CK and blood lactate concentration increased gradually after the third and sixth swimming bouts. % Dec in Cr group was significantly lower after 3rd swimming bout, also heart rate in Cr group was associated with lower increase in HR mean (P<0.05) compared to placebo. These results suggest that Cr supplementation may improve swimming performance and reduce increased blood lactate levels following intermittent sprint swimming bouts. In conclusion Cr supplementation in trained swimmers may improve anaerobic performance and heart rate variations independent of the effect of intensive sprint swimming bouts.
Subject(s)
Athletic Performance/physiology , Creatine/administration & dosage , Dietary Supplements , Muscle Fatigue/drug effects , Swimming/physiology , Adolescent , Heart Rate/physiology , Humans , Lactic Acid/blood , Male , Young AdultABSTRACT
Gliclazide is practically insoluble in water and its GI absorption is limited by its dissolution rate. Our previously published works indicated that preparing gliclazide-crosspovidone solid dispersion in the drug/ carrier ratio of 1:1 using cogrinding technique is able to enhance drug dissolution rate. The coground of gliclazide-crosspovidone was administrated to the rats and the hypoglycemic effects of pure drug, a physical mixture and the coground were considered in 3 groups of rats weighing 200-250 g (n=6). The rats were made diabetic by single intravenous administration of streptozotocin (60 mg/kg). Each of the rats received a single dose of gliclazide (equivalent to 40 mg/kg) as pure drug, physical mixture and coground in an aqueous suspension. Glucose level was assessed via glucometer after collecting the blood samples from tail vein. Gliclazide concentration in plasma was assessed applying high pressure liquid chromatography. According to 1-way ANOVA, Student-Newman-Keuls test, the coground revealed enhanced hypoglycemic effects as well as higher serum gliclazide concentration relative to pure drug and its corresponding physical mixture in the all sampling times. The area under serum glucose concentration curve vs. time for the pure gliclazide, physical mixture and coground formulations were 3 090.5±79, 3 018.8±96 and 2 374.0±73 mg.h/dl, respectively. Correspondingly, their area under serum gliclazide concentration curve vs. time were 1 171.8±156.8, 1 379.5±96.2 and 4 827.7±637.5 µg.h/ml. It follows that; formulation of gliclazide-crosspovidone coground is able to improve oral absorption of the drug.
Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Gliclazide/therapeutic use , Hypoglycemic Agents/therapeutic use , Animals , Blood Glucose/analysis , Diabetes Mellitus, Experimental/blood , Drug Carriers , Gliclazide/blood , Male , Rats , Solubility , StreptozocinABSTRACT
BACKGROUND: Copper (Cu) is an essential trace element involved in normal reproduction but its overexposure may produce some detrimental effects. The aim of this study was to investigate the effects of copper sulfate poisoning on morphometery of mice ovarian structures and probable intracellular changes. METHODS: Thirty mature female mice were randomly allocated to control and two treatment groups. In treatment groups, two different doses of copper sulfate including 100 mg/kg and 200 mg/kg in 0.2 cc were applied once a day for 35 consecutive days by gavage. Control animals received normal saline using the same volume and similar method. Animals from each experimental group were sacrificed 14 and 35 days after the beginning of drug administration and the left ovaries were removed for stereological evaluations by light microscopy and right ovaries were obtained for preparing electron microscopic sections. RESULTS: The morphometrical results showed that only the number of antral follicles was decreased by 100 mg/kg copper sulfate on day 14 compared to the control group (P=0.043). Hence, higher copper dose or longer consumption period significantly reduced different classes of follicles and corpora lutea. With 100 mg/kg copper sulfate some mild ultrastructural cell damages such as decrease of zona pellucida thickness, limited vacuolated areas and nuclear envelop dilation were seen on day 14. Higher or longer Cu administration produced more detrimental effects including more vacuolated areas, presence of secondary lysosomes, irregularity in cell shape and segmented nuclei with condensed and marginated chromatin and more enlarged and damaged mitochondria. CONCLUSION: New evidences of early as well as late intracellular damages of copper has been presented by accurate stereological and ultrastructural methods. Antral follicles was the most susceptible cells with the lower and shorter copper consumption and long term or higher dose of copper affected the whole of ovarian structures.
ABSTRACT
The objective of this study was to investigate the effects of dopamine as vasodilator, vitamin C as an antioxidant and combined administration of them on ischaemia-reperfusion (I-R) injury following testicular torsion (TT). Thirty adult male rats were divided into six groups each containing five rats. Testicular ischaemia was achieved by twisting the left testis for 4 h. Group 1 was for determination of the basal values. Group 2 had 4 h TT. Group 3 had 4 h TT and was then treated with dopamine. Group 4 had 4 h TT and was then treated with vitamin C. Group 5 had 4 h TT and was then treated with dopamine and vitamin C. Group 6 was designed as a sham operated group. Testicular torsion caused a significant decrease in the percentage of spermatogenesis and seminiferous tubules diameters compared with the control and sham groups. Administration of dopamine, vitamin C and their combination increased above mentioned parameters and decreased serum malondialehyde levels significantly. However, vitamin C had better results than the other treatments (P < 0.05). In conclusion, a potent antioxidant like vitamin C was found to be more effective than increasing blood flow by a vasodilator like dopamine on improving I-R injury following TT.
Subject(s)
Antioxidants/administration & dosage , Ascorbic Acid/administration & dosage , Dopamine/administration & dosage , Reperfusion Injury/drug therapy , Spermatic Cord Torsion/complications , Vasodilator Agents/administration & dosage , Animals , Drug Therapy, Combination , Male , Malondialdehyde/blood , Rats , Rats, Sprague-Dawley , Reperfusion Injury/etiology , Seminiferous Tubules/pathology , Spermatic Cord Torsion/pathology , SpermatogenesisABSTRACT
Canine herpes virus-1 (CHV-1) is an alphaherpesvirus, which causes foetal and neonatal death as well as fertility problems in dogs. The virus is presumed to be enzootic in dogs all over the world, but no information was found about the seroprevalence of CHV-1 from middle-east countries. Therefore, this study was aimed to determine the seroprevalence of CHV-1 among dogs in Kerman (south-east of Iran). Blood samples were taken from 47 privately owned and 35 kennelled dogs, respectively. The entire sampled dogs were apparently healthy. Indirect immunofluorescence antibody (IFA) assay was used to detect antibodies against CHV-1 in all sera. The overall CHV-1 seroprevalence was estimated 20.7%, which was 22.9% and 19.1% for kennelled and owned dogs, respectively. Sex, parity and raising status (owned or kennels) did not differ significantly between seropositive and seronegative dogs. However, the infection rate was significantly higher in dogs older than 3 in comparison with younger groups (15.9% vs. 4.8%, P ≤ 0.05). In conclusion, this study revealed that CHV-1 could be considered endemic in Iran, and more epidemiological researches are needed to identify the geographical distribution of diseases in Iran.
Subject(s)
Dog Diseases/blood , Herpesviridae Infections/veterinary , Herpesvirus 1, Canid/immunology , Animals , Dog Diseases/epidemiology , Dog Diseases/virology , Dogs , Female , Herpesviridae Infections/blood , Herpesviridae Infections/epidemiology , Herpesviridae Infections/virology , Iran/epidemiology , MaleABSTRACT
This study was set to investigate whether the adverse effects of heat on spermatozoa and subsequent foetuses could be prevented by long-term zinc administration. The scrotums of animals were immersed in water at either 43 degrees C (heat group) or 23 degrees C (control group). Half of the heat and control mice were given 10 mg kg(-1) zinc every other day for 60 days and the others received sterile saline instead of zinc. Heat stress significantly reduced sperm motility, concentration, hypoosmotic swelling-water test (HOS-WT) positive and chromomycin A(3) (CMA(3)) negative spermatozoa at the first 15 days, and the greatest decrease occurred at 30 days (P < 0.05). Sperm motility, concentration and HOS-WT positive spermatozoa were also reduced initially in the zinc administered group, but we did not observe any further decrease in the above mentioned parameters on day 30 (P < 0.05). The weight of foetuses obtained from the females mated with paternal heat treatment males was significantly lower than that of the control group (P < 0.05) and long-term zinc therapy caused a partial recovery (P > 0.05). This study demonstrates that the adverse effects of hyperthermia on semen parameters may be prevented by zinc therapy. Likewise, long-term administration of zinc could improve quality of litter obtained from the females mated with scrotal heat treatment males.
Subject(s)
Heat Stress Disorders/physiopathology , Hot Temperature/adverse effects , Infertility, Male/etiology , Spermatozoa/drug effects , Zinc Sulfate/therapeutic use , Animals , Female , Fetus/drug effects , Male , Mice , Pregnancy , Pregnancy Outcome , Protamines/drug effects , Scrotum , Semen Analysis , Sperm Count , Sperm Motility/drug effects , Zinc Sulfate/administration & dosageABSTRACT
The purpose of this study was to prepare recombinant K26 antigen from Leishmania infantum and evaluate its performance by enzyme-linked immunosorbent assay (ELISA) test for serodiagnosis of visceral leishmaniasis (VL) in endemic regions of Iran. The results were compared with those obtained by direct agglutination test (DAT) and whole cell ELISA using crude parasite antigen. Of 93 sera from patients with confirmed VL, 90 sera were positive with rK26 ELISA (sensitivity=96.8%), whereas 85 sera were positive with DAT (sensitivity=91.4%) and 89 sera were positive with whole cell ELISA (sensitivity=95.7%). Of 130 subjects who either had other infectious diseases (n=30) or were healthy (n=100), rK26 ELISA were negative in all cases (specificity=100%), whereas DAT were negative in 116 cases (specificity=89.2%) and whole cell ELISA was negative in 114 cases (specificity=87.7%). The results of this study indicate that the rK26 ELISA is more sensitive and specific than conventional methods and could be used for reliable diagnosis of VL caused by Leishmania infantum.
Subject(s)
Enzyme-Linked Immunosorbent Assay , Leishmania infantum , Leishmaniasis, Visceral/diagnosis , Agglutination Tests , Animals , Child , Child, Preschool , Humans , Iran , Leishmania infantum/immunologyABSTRACT
This study examined the activities of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in the milk of lactating Holstein cows in association with subclinical mastitis (SCM). A total of 94 milk samples were collected from 58 lactating dairy cows representing stages of lactation from the second to the tenth week after calving. Those which were classified as positive by California mastitis test (CMT) were deemed to have subclinical mastitis. All the milk samples were skimmed by centrifugation at 10 000g at 0 degrees C and were used for enzyme activities estimations. The mean activities of LDH and ALP were higher in the milk from udders with SCM than in the milk from healthy udders (p < 0.05). There were no significant differences in AST values. The maximum agreement rates between the CMT results and LDH and ALP values were seen at thresholds of > 180 IU/L and > 40 IU/L respectively (kappa values 0.65 and 0.79, respectively). However, the sensitivity of the tests for identifying SCM at these thresholds was higher for ALP (96.4%) than for LDH (68.5%). In this study, LDH and ALP tests were standardized for cow's milk and results showed that only the ALP test was reliable in the early diagnosis of subclinical mastitis.
Subject(s)
Alkaline Phosphatase/metabolism , Aspartate Aminotransferases/metabolism , L-Lactate Dehydrogenase/metabolism , Mastitis, Bovine/diagnosis , Mastitis, Bovine/enzymology , Milk/enzymology , Animals , Cattle , FemaleABSTRACT
The purpose of this study was to evaluate the development of vitrified-warmed mouse blastocysts following a period of Vitamin A administration. Four to six weeks old BALB/c mice were given an intraperitoneal injection of either 0.1 ml paraffin oil alone (control, Con) or paraffin oil containing 250IU of Vitamin A (experiment, Exp). Ten days later the mice were given second paraffin or paraffin Vitamin A injection and an injection of 10IU equine chorionic gonadotropin (eCG) followed 48 h later by 10IU human chorionic gonadotropin (hCG). Blastocysts were collected from both groups and randomly divided into non-vitrified (Con 1, Exp 1) and vitrified (Con 2, Exp 2) subgroups. Embryos in the vitrified group were exposed sequentially to two solutions (10% ethylene glycol, 10% DMSO in holding medium (HM: DMEMF(12)+10% FBS) and 20% ethylene glycol, 20% DMSO in HM) before plunging into liquid nitrogen. After warming at 37 degrees C, cryoprotectants were diluted serially with 0.25 and 0.15M sucrose solution in HM. The vitrified-warmed and the fresh embryos of the control and the experiment groups were cultured in DMEMF(12) with 10% FBS for 72 h. Although, on the first day of culture, the rate of development to the hatched blastocyst was nearly identical between the two vitrified groups (15.8% versus 13%) but after 48 h, the rate of plated embryos was statistically higher in the vitrified Vitamin A than the vitrified control group (63.1% versus 19.6%, P<0.001). After 48 h, in the non-vitrified groups, the rate of the plated embryos was also significantly higher in the Vitamin A than the control group (70.5% versus 49.3%, P<0.01). These data provided evidence that systemic administration of Vitamin A may enhance the potential development of blastocysts in culture and is capable to reduce the adverse effects of vitrification at least during the first 2 days of cultivation.
Subject(s)
Blastocyst/drug effects , Cryopreservation/veterinary , Cryoprotective Agents/pharmacology , Vitamin A/pharmacology , Animals , Blastocyst/physiology , Cryopreservation/methods , Embryonic Development/physiology , Female , Male , Mice , Mice, Inbred BALB C , PregnancyABSTRACT
Iron overload is known to occur due to different factors including genetic disorders. It has been shown that iron overload predisposes humans to an increased risk of cancer. However, the mechanism by which iron overload enhances chemically induced carcinogenesis is not known. In this report, for the first time it is shown that iron overload acts as a tumour initiator. Female albino Swiss mice were given iron dextran 1 mg/mouse per day intramuscularly for 15 days and croton oil 0.5 mg in 200 microL acetone/mouse topically twice a week for 30 weeks. During this period, the animals were observed for tumour incidence. There were significantly higher yields of tumours in those animals receiving both iron and croton oil. However, the group of animals treated only with acetone, iron, croton oil and 7,12-dimethylbenz(a)anthracene (DMBA) alone did not develop any tumours during 30 weeks of observation. Further, croton oil-mediated induction in cutaneous lipid peroxidation (LPO) level was higher in the iron-overload group. The results of this study suggest that oxidative stress generated by iron overload is responsible for croton oil-mediated skin carcinogenesis.