Hepatotoxicity and nephrotoxicity in rats induced by carbon tetrachloride and the protective effects of Teucrium polium and vitamin C

This work investigated the protective effects of Teucrium polium (T. polium) and vitamin C (Vit C) against carbon tetrachloride (CCl₄) induced hepatotoxicity and nephrotoxicity in rats. T. polium reduced the Fer reduced antioxidant power (FRAP) (IC₅₀?=?0.89?mg/ml) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) (IC₅₀?=?0.049 µg/ml) than Vit C, FRAP (IC₅₀?=?0.71?mg/ml) and DPPH (IC₅₀?=?0.029 µg/ml). Male albino Wistar rats were divided into six groups: Group I was used as controls, Group II received CCl₄ in olive oil (0.5?ml/kg) by gavage, Group III received CCl₄ in olive oil (0.5?ml/kg) by gavage after 3 d of receiving T. polium (5?g/l), orally, Group IV received T. polium (5?g/l) alone, by gavage, for 7 d, Group V received CCl₄ in olive oil (0.5?ml/kg) by gavage after 3 d of receiving Vit C (250?mg/kg) by gavage and Group VI received Vit C (250?mg/kg) alone by gavage. CCl₄ showed an increase of serum hepatic and renal markers aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine. Moreover, we noted an increase of lipid peroxidations and a decrease in antioxidants enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) of CCl₄ rats compared to controls. The pretreatment with (200?mg/kg) of T. polium and with Vit C (250?mg/kg) by gavage, for 7 d, displayed their ability to protect against oxidative damage and biochemical changes induced by CCl₄. Our results were in accordance with histopathological observations.     

Protective effect of olive oil and colocynth oil against cadmium-induced oxidative stress in the liver of Wistar rats

Cadmium (Cd) is one of the most common heavy metal pollutants. It is accumulated particularly in liver and kidney. The present study examined the possible protective effect of olive oil and colocynth oil consumption against Cd-induced damage on plasma lipids and stress biochemical parameters of rats. Male albino Wistar rats were randomly divided into 6 groups of 5 animals each and treated orally with Cd (50 mg/l), olive oil and colocynth oil (4%) alone or in combination with cadmium for 8 weeks. It was shown that Cd exposure induced significant increases in the activities of serum alanine aminotransferase, aspartate aminotransferase, lipid peroxidation levels (MDA) and protein carbonyl contents in exposed groups of rats compared to control group while the antioxidant enzymes, reduced glutathione and vitamins (C, A and E) were significantly decreased. Co-treatment with olive oil or colocynth oil significantly improved the oxidative damage induced by Cd. The antioxidant potential in plasma and liver were markedly restored with a significant decline in MDA levels and activity of transaminases.In conclusion, these results suggest that olive oil or colocynth oil consumption could protect the rat liver against Cd-induced injury by increasing the activities of antioxidant enzymes and reducing oxidative stress.     

Syringic acid ameliorates l-NAME-induced hypertension by reducing oxidative stress

The objective of the present study was to investigate the effects of syringic acid (SA), a phenolic acid, on N^ω-nitro-l-arginine methyl ester (l-NAME)-induced hypertensive rats. Hypertension was induced in adult male albino rats by oral administration of l-NAME (40?mg/kg/day) dissolved in drinking water daily for 4?weeks. Rats were treated with different doses of SA (25, 50, and 100?mg/kg body weight (b.w.)). Systolic blood pressure of control and experimental rats was recorded. Plasma nitric oxide metabolites (NOx), lipid peroxidative products such as thiobarbituric acid reactive substances, lipid hydroperoxides, conjugated dienes, and antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, vitamin C, vitamin E, and reduced glutathione were estimated in erythrocytes, plasma, and tissues of experimental rats. Hepatic marker enzymes such as aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase and renal functional markers such as urea, uric acid, and creatinine were also estimated in serum. The increased levels of blood pressure, lipid peroxidation products, hepatic and renal function markers, and the decreased level of NOx and antioxidants in l-NAME-induced hypertensive rats were reversed upon SA treatment. The protective effect at the dose of the three tested doses (25, 50, and 100?mg/kg) of SA at a dose of 50?mg/kg b.w. exerts optimum protection. Biochemical findings are substantiated by the histological observation. The protective effects of SA are mediated by reducing oxidative stress and retaining the bioavailability of NO in the cardiovascular system.     

Expression of Concern: Preventive effect of nerolidol on isoproterenol induced myocardial damage in Wistar rats: Evidences from biochemical and histopathological studies

The present study aimed at investigating the protective effects of nerolidol (NRD) against myocardial infarction (MI) induced by isoproterenol (ISO) in Wistar rats. The rats were randomly divided into five groups, each group consisting of six rats. Group I were treated as control rats, group II received NRD (200 mg/kg b.w.) by intragastric intubation for 21 days, group III received ISO (60 mg/kg b.w) subcutaneously (s.c) for two consecutive days on 22nd and 23rd day, group IV and V received NRD (100 and 200 mg/kg b.w) as in group II and additionally ISO was given for two consecutive days (22nd and 23rd). On 24th day all the rats were sacrificed by cervical dislocation and the blood and heart samples were collected. In the present study, ISO-induced myocardial damage was indicated by the changes in body weight, heart weight and the cardiac and hepatic marker enzymes such as creatine kinase (CK), creatine kinase-MB (CK-MB), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and troponin T and I (cTnT, cTnI) in the serum. In addition, the levels of lipid peroxidation products such as thiobarbituric acid reactive substances (TBARS), conjugated dines (CD), and lipid hydroperoxides (LHPs) increased significantly in the plasma and heart tissue. Activities of enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) in erythrocytes and heart tissue and the levels of nonenzymatic antioxidants like vitamin C, vitamin E, and reduced glutathione (GSH) in plasma and heart tissue were decreased in ISO-induced rats. Histopathological observations were also supported with the biochemical parameters. Pretreatment with NRD at different doses (100 and 200 mg/kg b.w) for 21 days prevented the above changes induced by ISO. The 200 mg/kg b.w of NRD was more pronounced than the other dose and brought back all the above parameters near to normalcy.     

Hepatoprotective effects of Juglans regia extract against CCl4-induced oxidative damage in rats

Abstract

Context: Different parts of the walnut [Juglans regia L. (Juglandaceae)] have been used in folk medicine for protection against liver injury, although its actual efficacy remains uncertain.

Objective: The present study investigated the protective effect of walnut leaf extract against carbon tetrachloride (CCl₄)-induced liver damage in rats.

Materials and methods: The rats were randomly divided into seven groups: control, CCl₄ (i.p., 0.5?mL/kg b.w., 50% CCl₄ in olive oil), walnut extract (at dose level of 0.2?g/kg b.w.) alone, walnut extract (at dose levels of 0.05, 0.1, 0.2 and 0.4?g/kg b.w.) with CCl₄, and treatment was carried out accordingly. On the 28th day, rats were sacrificed and blood was withdrawn by cardiac puncture. Liver damage was assessed by serum biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and albumin), antioxidant enzymes (superoxide dismutase and catalase) and histopathological observation.

Results: Administration of walnut leaf extract (ranging from 0.2 to 0.4?g/kg b.w.) significantly lowered serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase levels in CCl₄-treated rats. Walnut leaf extract increased antioxidant enzymes, including superoxide dismutase and catalase. Histopathological examination of livers showed that walnut leaves extract reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl₄-treated rats.

Discussion and conclusion: These results suggest that walnut extract has a protective effect over CCl₄-induced oxidative damage in rat liver. These results demonstrate that walnut extract acts as a good hepatoprotective and antioxidant agent in attenuating hepatocellular damage.     

The effects of alpha-tocopherol on the toxicity, disposition, and metabolism of adriamycin in mice.

Fourteen days after adriamycin treatment, 15 mg/kg ip, there was greater than 50% mortality in CDF₁ mice pretreated with either olive oil or saline ip, but only 5% mortality in animals pretreated with a single dose of α-tocopherol. However, 60 days after adriamycin, mortality was 80±5% in all three groups. A single dose of α-tocopherol alone caused no deaths. Blood concentrations of [¹⁴C]adriamycin-derived radioactivity in mice pretreated with α-tocopherol of olive oil were significantly higher than those of saline controls between 3 and 15 min after injection. At 30 and 60 min blood concentrations of radioactivity did not differ in the three groups. Sixty minutes after adriamycin administration, concentrations of radioactivity in heart, kidney, muscle, and lung were significantly higher in the α-tocopherol and olive oil groups than in the saline controls. No differences in the metabolic profile of adriamycin were found in heart or liver, but renal concentration of adriamycin and several metabolites were higher in both the α-tocopherol and olive oil groups. In general, α-tocopherol pretreatment had only slight effect on the metabolism of adriamycin in vivo. Thus, the time-dependent efficacy of α-tocopherol in ameliorating the lethal toxicity of adriamycin in mice does not appear to result from acute changes in the distribution or metabolism of adriamycin. It appears that the effect of α-tocopherol is to delay rather than prevent the lethal toxicity of adriamycin.     

The protective effects of astaxanthin against cisplatin-induced retinal toxicity

Purpose: This study investigated the toxic effects of an antineoplastic agent, cisplatin (CIS), on retinal cells and the potential capacity of astaxanthin (ASTA) to elicit a future therapeutic protocol in CIS-induced retinal toxicity.

Materials and methods: Six groups were formed for the assessment; control (healthy; Group 1), olive oil (olive oil only; Group 2), ASTA control group (ASTA only, Group 3), the single intraperitoneal (IP) dose of 16?mg/kg CIS (CIS only group; Group 4), 16?mg/kg CIS +25?mg/kg (IP) ASTA (Group 5), and 16?mg/kg CIS +75?mg/kg (IP) ASTA (Group 6). On the third day after CIS administration, rats in all groups were sacrificed under anesthesia and the analysis of the biochemical parameters and histopathological levels were performed.

Results: A significant decrease in GSH levels and increases in MDA, eNOS, and 8-OHdG expressions were recorded. Additionally, CIS treatment had caused acidophilic staining in retinal histological appearance. ASTA treatment reduced the increases in MDA, eNOS, and 8-OHdG levels following CIS administration and increased the levels of GSH expressions, as well.

Conclusions: These results may suggest that the ASTA molecule as a promising option to prevent retinal toxicity in patients receiving CIS treatment for malignant tumors.     

The protective role of Tropaeolum majus on blood and liver toxicity induced by diethyl maleate in rats

The protective role of Tropaelum majus (T.majus) methyl alcohol extract and vitamin E in the case of toxic effect induced by diethyl maleate was evaluated. Forty-two male albino rats were divided into seven groups of six rats each for 15 days. Group 1: normal control group. Group 2: taken daily oral dose of paraffin oil (0.25?ml/100?g b.wt rat). Group 3: received daily oral dose of vitamin E (100?mg/kg b.wt rat). Group 4: taken daily oral dose of 10% of the LD₅₀ of T.majus methyl alcohol extract. Groups 5–7: injected intra-peritoneally with diethyl maleate (5 μl/100?g b.wt rat) but groups 6 and 7 received a daily oral dose of either vitamin E or 10% of the LD₅₀ of T.majus methyl alcohol extract 1?h prior to diethyl maleate injection. The present results revealed that diethyl maleate induced serum aspartate and alanine aminotransferases enzymes activities decreased in serum, but their activities in the hepatic tissue showed an increase. Glutathione and glucose-6-phosphate dehydrogenase levels showed a decrease, but thiobarbituric acid reactive substances level showed an increase in both serum and liver tissue. Serum and liver proteins decreased in serum and liver tissue. A significant decrease in blood parameters (hemoglobin, hematocrit, as well as red and white blood cells) and serum glucose occurred. Histopathological results showed that diethyl maleate induced a hoop of edema in the hepatic periportal area; while T.majus methyl alcohol extract or vitamin E prior to diethyl maleate injection shift blood and liver toxicity induced by diethyl maleate towards normal values and preserved hepatic lobular architecture. In conclusion, pre-treatment with either T.majus methyl alcohol extract or vitamin E provide protection against blood and liver toxicity induced by diethyl maleate in rats, these results were confirmed by histological examinations.     

Effect of Cyclosporin on Liver Antioxidants and the Protective Role of Vitamin E in Hyperoxaluria in Rats

This study aimed to evaluate whether administration of cyclosporin to hyperoxaluric rats affects liver antioxidant status, and whether pretreatment with vitamin E reverses the effect. Male Wistar rats were divided into two major groups of 40. One group was given vitamin E. Both major groups were then divided into four subgroups which received vehicle (olive oil), cyclosporin in olive oil (50 mg kg^?1), 3% ammonium oxalate or cyclosporin + 3% ammonium oxalate for three days. The activities of liver lactate dehydrogenase, glycolic acid oxidase and xanthine oxidase, and the level of malondialdehyde, an indicator of lipid peroxidation, increased when cyclosporin was administered to hyperoxaluric rats. The levels of antioxidants ascorbic acid, vitamin E and reduced glutathione and the activities of glutathione-metabolizing enzymes were altered significantly when hyperoxaluric rats were treated with cyclosporin. All these enzymes and antioxidants showed highly significant correlation values, r. These changes were restored to near normal by pretreatment with vitamin E. These findings suggest that cyclosporin-induced hepatotoxicity is aggravated in hyperoxaluria. This was almost totally prevented by pretreatment with vitamin E.     

Pharmacological dose of {alpha}-tocopherol induces cardiotoxicity in Wistar rats determined by echocardiography and histology

The effect of pharmacological dose of α-tocopherol on heart health was determined in Wistar rats. Animals were randomly assigned to either C (control, n = 11) or E (α-tocopherol, n = 11) group. Animals received corn oil (C) or α-tocopherol dissolved in corn oil (250 mg α-tocopherol/[kg body wt/day]) (E) by gavage for a 7-week period. Rats underwent echocardiogram and were analyzed for cardiomyocyte histology and cardiac α-tocopherol absorption at the end of the study period. As compared to the C group, α-tocopherol-supplemented group showed significantly (p < 0.05) lower body weight (E, 412.8 g vs C, 480.3 g) and total cardiac weight (E, 0.94 g vs C, 1.08 g); cardiomyocyte histological impairment; smaller left ventricle (LV) (LV end-diastolic diameter (E, 7.22 mm vs C, 7.37 mm), lower LV systolic [left ventricle fractional shortening (E, 47.6% vs C, 53.6%) and ejection fraction ratio (E, 85.4 vs C, 89.9)] and diastolic [early peak velocities of diastolic transmitral flow (E, 64.6 cm/sec vs C, 75.1 cm/sec)] function. The α-tocopherol uptake in target tissue was confirmed by determination of α-tocopherol concentration medians in cardiac tissue (E, 109.91 nmol/kg vs C, 52.09 nmol/kg). The current study indicates that pharmacological dose of α-tocopherol supplementation can induce cardiotoxicity in healthy rats.     

The protective role of Tropaeolum majus on blood and liver toxicity induced by diethyl maleate in rats

The protective role of Tropaelum majus (T.majus) methyl alcohol extract and vitamin E in the case of toxic effect induced by diethyl maleate was evaluated. Forty-two male albino rats were divided into seven groups of six rats each for 15 days. Group 1: normal control group. Group 2: taken daily oral dose of paraffin oil (0.25ml/100g b.wt rat). Group 3: received daily oral dose of vitamin E (100mg/kg b.wt rat). Group 4: taken daily oral dose of 10% of the LD50 of T.majus methyl alcohol extract. Groups 5–7: injected intra-peritoneally with diethyl maleate (5 μl/100g b.wt rat) but groups 6 and 7 received a daily oral dose of either vitamin E or 10% of the LD50 of T.majus methyl alcohol extract 1h prior to diethyl maleate injection. The present results revealed that diethyl maleate induced serum aspartate and alanine aminotransferases enzymes activities decreased in serum, but their activities in the hepatic tissue showed an increase. Glutathione and glucose-6-phosphate dehydrogenase levels showed a decrease, but thiobarbituric acid reactive substances level showed an increase in both serum and liver tissue. Serum and liver proteins decreased in serum and liver tissue. A significant decrease in blood parameters (hemoglobin, hematocrit, as well as red and white blood cells) and serum glucose occurred. Histopathological results showed that diethyl maleate induced a hoop of edema in the hepatic periportal area; while T.majus methyl alcohol extract or vitamin E prior to diethyl maleate injection shift blood and liver toxicity induced by diethyl maleate towards normal values and preserved hepatic lobular architecture. In conclusion, pre-treatment with either T.majus methyl alcohol extract or vitamin E provide protection against blood and liver toxicity induced by diethyl maleate in rats, these results were confirmed by histological examinations.     

Effect of α-tocopherol on carbon tetrachloride intoxication in the rat liver

Carbon tetrachloride (1 ml/kg body weight as a 1:1 mixture of CCl₄ and mineral oil) was orally administered to rats. After 12 h, the activity of plasma ALT (alanine aminotransferase) was significantly higher than that of the control group, and plasma ALT and AST (aspartate aminotransferase) activities significantly increased 24 h after CCl₄ administration. These results indicated that the necrotic process had initiated at about 12 h and developed thereafter. After 6–24 h of CCl₄ administration, the hepatic level of vitamin C, the most sensitive indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced 6 h after CCl₄ intoxication and thereafter. Oral administration of vitamin E (1 ml/kg body weight as a 1:1 mixture of α-tocopherol and mineral oil) 12 h before CCl₄ administration caused a significant elevation of liver vitamin E level and ameliorated liver necrosis 24 h after CCl₄ intoxication based on plasma AST and ALT. Vitamin E also significantly restored the hepatic vitamin C concentration 12 and 24 h after CCl₄ intoxication, demonstrating that vitamin E functioned as an antioxidant. The liver vitamin E concentration was not changed by vitamin E supplementation to rats that did not receive CCl₄. This result indicated that vitamin E accumulated in the damaged liver. The activation of JNK, ERK1/2 and p38 MAPK took place 1.5 h after CCl₄ administration. Co-administration of α-tocopherol with CCl₄ did not affect these early changes in MAPKs.     

Protective effect of olive oil minor polar components against oxidative damage in rats treated with ferric-nitrilotriacetate

The phenolic fraction of virgin olive oil exerts preventive effects against reactive oxygen species mediated degenerative diseases. To investigate its action as inhibitor of lipid peroxidation in vivo, we treated Wistar rats with olive oil minor polar components (MPC) (25–50 mg/kg bw) prior to the administration of a sublethal dose (15 mg Fe/kg bw) of ferric-nitrilotriacetate (Fe-NTA). Intraperitoneal injection (i.p.) of Fe-NTA lead to increased oxidative stress associated with extensive peroxidation of membrane lipids in plasma, kidney, and liver of treated rats. Fe-NTA treatment induced a significant decrease of the major oxidizable membrane lipids, -tocopherol, fatty acids and cholesterol, together with an increase of fatty acids hydroperoxides (HP) and 7-ketocholesterol (7-keto). I.p. administration of MPC significantly inhibited fatty acids and cholesterol oxidation, and reduced the levels of HP and 7-keto. In summary, MPC administration protects organs against lipid peroxidation and conserves the endogenous -tocopherol.     

Therapeutic effect of Kalpaamruthaa,a herbal preparation on adjuvant induced arthritis in wistar rats

The present study was performed in order to establish the efficacy of Kalpaamruthaa (KA), a modified indigenous Siddha preparation in adjuvant induced arthritic rat (AIA) model with reference to mediators of inflammation (lysosomal enzymes) and its effect on proteoglycans. Albino rats of Wistar strain were divided into seven Groups of six animals each. Arthritis was induced to rats by subcutaneous injection of 0.1 ml of Complete Freund’s Adjuvant into the plantar surface of the left hind paw. Group I served as normal control rats receiving 0.5 ml of olive oil as vehicle, Group II arthritic rats served as induced-untreated and Group III (50 mg/kg), Group IV (100 mg/kg), Group V (150 mg/kg), Group VI (200 mg/kg) and Group VII (250 mg/kg) were KA treated rats at different dose levels orally in 0.5 ml of olive oil from 14^th day of adjuvant injection and was terminated on day 28. Animals were then sacrificed on the day 29, blood was collected, liver and kidney were dissected out, washed and 10% homogenates were prepared. The activities of lysosomal enzymes (β-glucuronidase, β-galactosidase, acid phosphatase, β-N-acetyl glucosaminidase and cathepsin-D), aminotransferases (alkaline phosphatase, aspartate and aminotransferases) and levels of plasma protein bound carbohydrate components of glycoproteins were determined and were found to be elevated in arthritic rats when compared to control animals. After administration of KA, the activities of lysosomal enzymes, aminotransferases and protein-bound carbohydrate component levels were significantly normalized. The data obtained evidently indicate that Kalpaamruthaa is effective at the dose of 150 mg/kg b.wt. in AIA and plays an important role in lysosomal membrane stabilization. This was further confirmed by radiological, histological and electron microscopic studies. Received 21 November 2006; revised 6 April 2007; accepted 13 April 2007     

Protective effects of vitamin E and C on cisplatin nephrotoxicity in developing rats

The kinetics of vitamin E was followed in serum, liver and kidney of 10- and 55-day-old rats after the administration of a single i.m. dose of 100 mg α-tocopherol acetate/100 g body wt. The basal levels without vitamin E administration were significantly higher in serum and liver of 10- than 55-day-old rats. The effect of vitamin E on cisplatin (CP; 0.6 mg/100 g body wt., i.p.) nephrotoxicity was investigated by determining urinary volume and protein excretion, as well as the concentration of blood urea nitrogen (BUN) and lipid peroxides in renal tissue (LPO). Previously described age differences in CP nephrotoxicity were confirmed. The administration of vitamin E, 12 h prior to CP, diminished the toxic effect of CP in young and adult rats. This effect could not be enhanced by a second administration of vitamin E. The simultaneous administration of vitamin E and C 12 h prior to CP intensified the protective effect of a single administration of vitamin E in 10- and 55-day-old rats without influencing the concentration of platinum in renal tissue. Received: 10 April 1997 / Accepted: 10 June 1997     

Oral supplementation with troxerutin (trihydroxyethylrutin), modulates lipid peroxidation and antioxidant status in 1,2-dimethylhydrazine-induced rat colon carcinogenesis

The present study was aimed to investigate the chemopreventive potential of troxerutin on 1,2-dimethylhydrazine (DMH) induced rat colon carcinogenesis by evaluating the antioxidant and lipid peroxidation (LPO) status. Rats were randomly divided into six groups. Group I rats served as control. Group II rats received troxerutin (50 mg/kg b.w., p.o.) for 16 weeks. Groups III–VI rats received subcutaneous injections of DMH (20 mg/kg b.w., s.c.) once a week, for the first 4 weeks. In addition to DMH, groups IV–VI rats received troxerutin at the doses of 12.5, 25 and 50 mg/kg b.w., respectively. In DMH treated rats, our results showed decreased activities of antioxidants and increased levels of LPO in the liver. Moreover, LPO and antioxidants in the colon were found to be significantly diminished in DMH the treated rats. Furthermore, enhanced activity of colonic vitamin C and vitamin E levels were observed in DMH alone treated rats (group III), which was significantly reversed on troxerutin supplementation. Troxerutin at the dose of 25 mg/kg b.w. had shown profound beneficial effects by exhibiting near normal biochemical profile and well-preserved colon histology as compared to the other two tested doses (12.5 and 50 mg/kg b.w.). These findings suggest that troxerutin could serve as a novel agent for colon cancer chemoprevention.     

Development of an Experimental Model for the Study of Hexachlorobenzene-Induced Hepatic Porphyria in the Rat

Development of an Experimental Model for the Study of Hexachlorobenzene-InducedHepatic Porphyria in the Rat. KRISHNAN, K., BRODEUR, J., ANDCHARBONNEAU, M. (1991). Fundam Appl. Toxicol 17, 433-441. Hexachlorobenzene(HCB) induces hepatic porphyria in rats. Various protocols ofrepeated cumulative and daily doses of HCB administered forseveral weeks until porphyria develops have been traditionallyused. In order to undertake studies on early biochemical eventsoccurring in HCB-induced porphyria, we have designed an experimentalmodel involving the administration of a minimal amount of HCBinducing a fully developed porphyria in a well defined and predictabletime frame. Groups of Sprague-Dawley rats were given (po, in10 ml/kg of corn oil) a cumulative dose of 1500 mg HCB/kg as50 mg/kg for 6 weeks (5 days/week) or 100 mg/kg for 3 weeks(5 days/week). In female, but not male, rats treated for 6 weeks,HCB caused a porphyria as measured by urinary uroporphyrin andhepatic porphyrin levels: this total dose given to female ratsin 3 weeks was not, however, porphyrinogenic. Female rats weregiven 12 consecutive daily doses of 50 mg HCB/kg followed bya no-treatment period of 30 days: this cumulative dose of 600mg HCB/kg induced a porphyria after 6 weeks. The approximateminimally effective cumulative dose inducing porphyria was determinedto be 400 mg HCB/kg, regardless of the magnitude of the dailydose (25, 50, or 100 mg/kg). Finally, the administration ofa cumulative dose of 500mg HCB/kg (50 mg/kg, 5 days/week for2 weeks or 100 mg/kg/day for 5 days) induced after 5 to 6 weeksa porphyna that persisted for more than 500 to 600 days. Theseresults suggest that induction of porphyria is dependent uponthe administration of a threshold cumulative dose of HCB duringan initial phase followed by a delay period with no furthertreatment during which full development of biochemical alterationsin the heme synthesis cycle occurs.     

Diazinon-induced hepatotoxicity and protective effect of vitamin E on some biochemical indices and ultrastructural changes

Diazinon, an organophosphate insecticide has been used in agriculture and domestic for several years. The aim of present study was to analyze the hepatotoxic effect of diazinon which caused biochemical and ultrastructural changes in adult male Wistar rats and to evaluate the possible protective effect of vitamin E. Vitamin E (200 mg/kg, twice a week), diazinon (10 mg/kg per day, once a day in corn oil) and vitamin E (200 mg/kg, twice a week)+diazinon (10 mg/kg per day, once a day in corn oil) combination were given to rats (n=8) orally via gavage for 7 weeks. Biochemical indices in serum [total protein, albumin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol, triglyceride and low density lipoprotein cholesterol (VLDL-cholesterol)] and ultrastructural changes were investigated at the end of the 1st, 4th and 7th weeks comparatively with control group (n=8). It was observed that; at the end of 1st week, there was a statistically significance in all parameters except total protein and albumin, and at the end of 4th and 7th weeks, there was a statistically significance in all parameters when diazinon-treated group compared to control group (P<0.01). At the end of 1st week, ALP, ALT, total cholesterol and triglyceride, at the end of 4th week, all parameters except VLDL-cholesterol, at the end of 7th week, all parameters were statistically significant when vitamin E+diazinon-treated group compared with diazinon-treated group (P<0.01). In our electron microscopic investigations, while swelling of mitochondria and breaking up of the mitochondrial cristae of hepatocytes in diazinon-treated groups were observing, no pathological findings were observed in vitamin E+diazinon-treated groups. We conclude that vitamin E decreases diazinon hepatotoxicity, but vitamin E does not protect completely.     

Relations between toxicity and altered tissue distribution and urinary excretion of nicotine,cotinine, and hydroxycotinine after chronic oral administration of nicotine in rats

Tissue distribution and urinary excretion of nicotine, cotinine, and hydroxycotinine after multiple oral administration of nicotine to rats for 4 weeks were studied. Physiological change and serum biochemical parameters were also measured to check dysfunction of organs. Significant change of glutathione S-transferase, aspartate aminotransferase, blood urea nitrogen, and physiological parameters indicated the toxicity in liver and kidney, at the dose of 5 and 10?mg/kg/day. Only the concentration and total amount of cotinine, not nicotine or hydroxycotinine, in the liver and the kidney showed a proportional dose-dependent increase and were highly correlated with toxicity. Saturation of metabolizing enzymes for nicotine was estimated by the change of urinary excreted amount ratio between nicotine and its metabolites. Metabolizing enzyme to produce cotinine from nicotine was saturated after multiple oral dosing for 4 weeks in a low dose (1?mg/kg/day), but within 1 week in the dose of 5 and 10?mg/kg/day.