Effect of vanadium on colonic aberrant crypt foci induced in rats by 1,2 Dimethyl hydrazine

Chemopreventive Activity of 80% Methanol Leaf Extract of Vernonia auriculifera Hiern (Asteraceae) Against Dimethylhydrazine-Induced Colorectal Carcinogenesis in Rats

Background

Vernonia auriculifera Hiern (Asteraceae) is among Ethiopian herbal medicines that are traditionally used to treat skin and gastrointestinal cancers. In this study, the chemopreventive potential of Vernonia auriculifera leaf extract in dimethylhydrazine (DMH)-induced colorectal carcinogenesis in rats was investigated.

Methods

Rats were assigned to nine groups (normal, positive, and negative control groups, and three pre- and three post-initiation groups). Except for the normal control group (administered with 1 mL/100 g distilled water), the remaining eight groups were given DMH (20 mg/kg) intraperitoneally (ip) for 15 consecutive weeks to induce colorectal tumours. The extract was given orally to the pre-initiation and post-initiation groups at doses of 100, 200, and 400 mg/kg before and after the induction of cancer, respectively. The positive control group was treated with aspirin (60 mg/kg/day) orally for the whole experimental period. Parameters including body weight, average tumour number, size, progression, incidence, total cholesterol, serum total protein, and triglyceride levels were determined. The cytotoxic activity of the extract in Caco-2 cells was evaluated using the MTT assay, and the antioxidant activity of the extract was also assessed using 2.2-diphenyl-1-picrylhydrazine (DPPH) and reducing power methods. Moreover, total phenol and flavonoid contents were determined using appropriate methods.

Results

Rats treated with the extract showed a lower incidence of up to 50% in the pre-initiation higher dose, average number (p<0.05),and size (p<0.05) of tumours compared to untreated rats. It also inhibited colorectal cancer-associated increases in serum total cholesterol and triglycerides. The extract's IC50 value in the MTT assay was found to be higher than 200 µg/mL. The extract had an IC50 of 74.88 ± 0.86 µg/mL and 84.69 ± 2.02 µg/mL in the reducing power and DPPH assays, respectively. Total flavonoid and phenol contents were 14.51 ± 0.41 mg quercetin acid equivalent/gm and 47.37 ± 0.72 mg gallic acid equivalent/gm of the crude extract, respectively.

Conclusion

The findings collectively indicated that the leaves of V. auriculifera possess chemopreventive activity, probably mediated through antioxidant mechanisms, which supports the traditional claim.

Biochemical and histopathological effects of low dose vanadium in the healing of acetic acid-induced colitis in male wistar rats

OBJECTIVES

Vanadium has been reported to possess relevant therapeutic properties such as anti-diabetic and anti-tumoral. This study aimed at determining the effects of vanadium on experimentally induced colitis in rats.

METHODS

Forty-five male Wistar rats (103 ± 3.90 g, n=15) were used for this study and were divided into three groups. Group 1 (Untreated control) had nothing added to their drinking, while groups 2 and 3 received sodium metavanadate at a dose of 50 and 200 mg/L respectively in their drinking water for 10 weeks. Colitis was thereafter induced by intra colonic administration of 1.50 mL of 6% acetic acid. Animals were sacrificed on day 0 (pre-induction), three- and seven-days post induction. Blood samples were collected for haematological variables and the distal 8 cm of the colon was collected for macroscopic, histological and biochemical (malondialdehyde-MDA, superoxide dismutase-SOD, catalase-CAT, glutathione peroxidase- GPx and nitrite concentration- NO) assessment.

RESULTS

Low dose vanadium proved beneficial in ameliorating acetic acid-induced colitis by improving both histopathological and haematological changes. Gross observation showed a faster healing rate in vanadium treated groups (50 and 200 mg/L) compared with untreated control at day 3 (40 and 26.20 vs. 2.50%) and day 7 (80 and 66.70 vs. 42%) respectively. Vanadium also appears to exert its beneficial effects on acetic acid-induced colitis via up regulation of antioxidant enzymes (SOD, CAT, GPx) and NO while decreasing the over production of MDA.

CONCLUSIONS

Vanadium at small concentration functions as an essential trace element and may be able to promote healing process during ulcerative colitis.

Sodium orthovanadate inhibits growth and triggers apoptosis of human anaplastic thyroid carcinoma cells in vitro and in vivo

Vanadium and its compounds exhibit concentration- and time-dependent anticancer effects on various types of tumor; however, the effects of sodium orthovanadate (SOV) on anaplastic thyroid carcinoma (ATC) have not yet been reported. In the present study, the anticancer effects of SOV on ATC were evaluated. In vitro experiments, including cell viability assays, plate colony formation assays, cell cycle analysis and apoptosis analysis were used to study the role of SOV in ATC. Using in vivo experiments, the effects of SOV on the growth and apoptosis of an ATC-xenograft tumor were studied by comparing the SOV-treatment with the control group. The results revealed that treatment of the human ATC cell line 8505C with SOV inhibited cell viability, induced G2/M phase cell cycle arrest, stimulated apoptosis and reduced mitochondrial membrane potential in a concentration-dependent manner. These findings were confirmed in vivo in a nude mouse ATC xenograft model. In conclusion, the present study demonstrated that SOV inhibited human ATC by regulating proliferation, cell cycle progression and apoptosis, thus suggesting that SOV may be considered a novel option for the treatment of ATC.

Deciphering the biochemical and molecular mechanism underlying the in vitro and in vivo chemotherapeutic efficacy of ruthenium quercetin complex in colon cancer

Flavonoids are the most investigated phytochemicals due to their pharmacological and therapeutic activities. Their ability to chelate with metal ions has resulted in the emergence of a new category of molecules with a broader spectrum of pharmacological activities. In this study, the ruthenium quercetin complex has been synthesized and anticancer activity has been evaluated on a well-defined model of DMH followed by DSS induced rat colon cancer and on human colon cancer cell line HT-29. The characterizations accomplished through UV-visible, NMR, IR, Mass spectra and XRD techniques, and antioxidant activity was assessed by DPPH, FRAP, and ABTS methods. In vitro study confirmed that the complex increased p53 expression, reduced VEGF and mTOR expression, apoptosis induction, and DNA fragmentation in the HT-29 cells. Acute and subacute toxicity study was also assessed and results from in vivo study revealed that complex was efficient to suppress ACF multiplicity and hyperplastic lesions and elevated the CAT, SOD, and glutathione levels. Furthermore, the complex was found to decrease cell proliferation and increased apoptotic events in tumor cells correlates upregulation of p53 and Bax and downregulation of Bcl2 expression. Our findings from the in vitro and in vivo study support the continued investigation of ruthenium quercetin complex possesses a potential chemotherapeutic activity against colon cancer and was efficient in reducing ACF multiplicity, hyperplastic lesions in the colon tissues of rats by inducing apoptosis.

Trivalent Chromium has no Effect on Delaying Azoxymethane-Induced Colorectal Cancer in FVB/NJ Mice

As Cr(III) compounds have been shown to increase insulin sensitivity and decrease plasma cholesterol and triglycerides in rodent models of diabetes and insulin resistance and as colorectal cancer risk has been associated with insulin resistance and diabetes, the effects of the Cr(III) compound Cr3 ([Cr3O(O2CCH2CH3)6(H2O)3](+)) were investigated in male and female FVB/NJ mice with azoxymethane-induced colorectal cancer. In contrast to a previous study on the effects of Cr3 on 1,2-dimethylhydrazine-induced colorectal cancer in Sprague Dawley rats, no effects of Cr3 at daily doses of 1 and 10 mg Cr/kg body mass were observed, leaving in question whether administration of Cr(III) compounds can delay or prevent the onset of colorectal cancer.

Antiproliferative efficacy of hesperetin (citrus flavanoid) in 1,2-dimethylhydrazine-induced colon cancer

Cancer is the second leading cause of death worldwide and is increasing at an alarming rate. The present study was to evaluate the antiproliferative effects of hesperetin, a flavonoid commonly found in many herbal medicines and foods, on aberrant crypt foci (ACF), argyrophylic nucleolar organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in rats. Rats were given subcutaneous injections of DMH (20 mg/kg body weight) weekly for 15 weeks to induce carcinogenesis, and hesperetin was administered orally at the dose of 20 mg/kg body weight. DMH exposure alone produced a high incidence of ACF and showed positive staining for PCNA and AgNORs in colonic tissues. Supplementation with hesperetin lowered the PCNA labeling index and suppressed the formation of ACF in the rats with colon cancer. These results clearly reveal that dietary hesperetin possesses antiproliferative ability against chemically induced colon tumourigenesis.

Nicotine attenuates spatial learning deficits induced by sodium metavanadate

Learning can be severely impaired as a consequence of exposure to environmental pollutants. Vanadium (V), a metalloid which is widely distributed in the environment, has been shown to exert toxic effects on a variety of biological systems including the nervous system. However, studies exploring the impact of vanadium on learning are limited. Herein, we investigated the effects of oral administration of sodium metavanadate (SMV) (15, 20 and 25mg/kg/day for 2weeks) on spatial learning using Morris water maze (MWM). Our results showed that pre-training administration of sodium metavanadate impaired learning in Morris water maze. Analyzing the role of cholinergic system in SMV-induced learning deficit, we found that bilateral intra-hippocampal infusion of nicotine (1μg/side) during training could significantly diminish the SMV-induced learning impairment. We next examined the expression of choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) as cholinergic markers in CA1 region of hippocampus as well as in medial septal area (MSA). Our molecular analyses showed that vanadium administration decreased ChAT and VAChT protein expression, an effect that was attenuated by nicotine. Altogether, our results confirmed the toxic effects of SMV on spatial acquisition, while also pointing to the neuroprotective effects of nicotine on SMV-induced impairments in learning capabilities. These findings might open a new avenue for the prevention of vanadium adverse effects on spatial learning and memory through activation of cholinergic signaling pathway.

Sodium butyrate does not decrease the evolution of precancerous lesions in rats

PURPOSE

To evaluate the preventive effect of sodium butyrate in the appearance of aberrant crypt foci (ACF) in rats after induction with the carcinogen 1,2-dimethylhydrazine (DMH).

METHODS

Forty Wistar rats were separated into four groups (n=10) distributed as follows: control 1, control 2, butyrate 1 and butyrate 2. The groups control 1 and butyrate 1 remained under experimentation for 4 weeks, while the groups control 2 and butyrate 2 remained for 8 weeks. In the first four weeks, the animals of the control groups received water ad libitum and the animals of the butyrate groups received a sodium butyrate solution (3.4%) ad libitum. Injections of the drug 1,2-dimethylhydrazine were applied during the two first weeks of the experiment in all the animals, concurrently with the application of sodium butyrate. The large intestine of the animals was removed, for the analysis of the ACF and of the content of polyamines. The animal feces were collected for the analysis of the SCFA profile.

RESULTS

The spermidine presented a higher concentration in the group butyrate 2 in comparison to the group control 2. There was a significant difference in the concentration value (µmol/mL) of acetate in comparison to the groups control 2 and butyrate 2.

CONCLUSION

The use of sodium butyrate together with the induction of colorectal cancer was not effective in the prevention of the disease progression.

Inhibitory effect of bread crust antioxidant pronyl-lysine on two different categories of colonic premalignant lesions induced by 1,2-dimethylhydrazine

Colorectal malignancies continue to be one of the most frequent and life-threatening diseases throughout the world. Pronyl-lysine, a product obtained from bread crust, is a potent free radical scavenging antioxidant exerting chemopreventive activity by reducing oxidative stress. This study was conducted to investigate the effects of pronyl-lysine supplementation on the formation of colonic precancerous lesions, circulatory lipid peroxidation, and enzymic antioxidant status in 1,2-dimethylhydrazine-induced colon carcinogenesis. Male Wistar rats were randomized into seven groups; group 1 was control rats, group 2 received pronyl-lysine (2 mg/kg body weight orally) everyday, rats in groups 3-7 were administered subcutaneous 1,2-dimethylhydrazine (20 mg/kg body weight) once a week for 15 consecutive weeks. In addition, group 4 (pre-initiation), 5 (initiation), 6 (post-initiation), and 7 (entire period) received pronyl-lysine (2 mg/kg body weight orally) everyday. At the end of 34 weeks, indicative markers of lipid peroxidation and changes in antioxidant defense system were measured in circulation. The results showed that 1,2-dimethylhydrazine significantly increased total aberrant crypt foci formation, total number of dysplastic foci, beta-catenin accumulated crypts and proliferating cell nuclear antigen labeling index in the colon, and enhanced lipid peroxidation markers and decreased enzymic antioxidant activities in the plasma and erythrocyte lysate as compared with untreated controls. Pronyl-lysine supplementation significantly reversed the changes as compared with the rats treated with 1,2-dimethylhydrazine alone. The effect of pronyl-lysine was more pronounced when supplemented throughout the study period (group 7). These findings suggest that pronyl-lysine suppresses 1,2-dimethylhydrazine-induced colon carcinogenesis effectively.

Vanadium in the detection, prevention and treatment of cancer: the in vivo evidence

Vanadium, a dietary micronutrient, is yet to be established as an essential part of the human diet. Over the past century, several biological effects of vanadium, such as insulin-mimetic action as well as amelioration of hyperlipidemia and hypertension, have been discovered. This transition element is known to influence a battery of enzymatic systems, namely phosphatases, ATPases, peroxidases, ribonucleases, protein kinases and oxidoreductases. Multiple biochemical and molecular actions of vanadium have been implicated in its inhibitory effects on various tumor cells of human origin. Successful in vitro studies over the past few decades have advanced the anticancer research on vanadium into the preclinical stage. Vanadium in several animal cancer models provides protection against all stages of carcinogenesis--initiation, promotion, and progression. This review focuses on the current advances in cancer prevention and treatment as well as early detection by vanadium compounds in preclinical animal models while pointing to possible mechanisms of such diverse beneficial effects. Clinical pharmacokinetic and potential toxicity studies on vanadium are also highlighted in this review. Supporting and challenging evidence as well as future directions of vanadium research exploring the possibility of using this dietary agent for detection, prevention and treatment of human cancers are critically discussed.

Effect of hesperetin, a citrus flavonoid, on bacterial enzymes and carcinogen-induced aberrant crypt foci in colon cancer rats: a dose-dependent study

Hesperetin, an important bioactive compound in Chinese traditional medicine, has antioxidant and anticarcinogenic properties. Hesperetin is found in abundance in orange and grape juices (200–590 mg L−1) consumed in the daily diet. We have investigated the effect of different doses of hesperetin on faecal and colonic mucosal bacterial enzymes and aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis in male Wistar rats. The rats were divided into six groups and were fed a modified pellet diet for 16 weeks. Group 1 served as control and group 2 received the modified pellet diet along with hesperetin (30 mg kg−1). The rats in groups 3–6 rats were given a weekly subcutaneous injection of DMH (20 mg kg−1) for the first four weeks. Hesperetin was supplemented orally at different doses (10, 20 or 30 mg kg−1) for a total of 16 weeks. At the end of the experimental period all rats were killed. In DMH-treated rats, the activity of faecal and colonic mucosal bacterial enzymes, such as β-glucuronidase, β-galactosidase, β-glucosidase, nitroreductase, sulfatase and mucinase, were significantly elevated, but in rats supplemented hesperetin along with DMH the activity was significantly lowered (P &lt; 0.05). The total number of aberrant crypts was significantly increased in unsupplemented DMH-treated rats, while hesperetin supplementation to DMH-treated rats significantly reduced the total number of crypts. The results demonstrated that hesperetin supplementation at a dose of 20 mg kg−1 played a potent role in suppressing the formation of aberrant crypt foci and reducing the activity of bacterial enzymes in colon cancer.

Chemomodulation of the antioxidative enzymes and peroxidative damage in the colon of 1,2-dimethyl hydrazine-induced rats by ellagicacid

Prevention of cancer remains a primary need and new chemopreventive agents must be developed for this purpose. Toward this goal, a chemopreventive study was conducted to evaluate the potential effect of ellagic acid (EA) against 1,2-dimethylhydrazine (DMH-) induced colon carcinogenesis in experimental rats. Rats were administered with DMH (20mg/kg body weight) subcutaneous injection once a week for 15 weeks and were supplemented with EA (60 mg/kg body weight/day orally). In the present study, the efficacy of EA on the formation of aberrant crypt foci (ACF), levels of lipid peroxidation (LPO) and activities of enzymic and non-enzymic antioxidants in DMH-induced colon-cancer-bearing rats were assessed. After the experimental period, frequency of ACF, levels of LPO were found to be increased, whereas a significant decrease in the activities of enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase) and non-enzymic antioxidants (reduced glutathione, vitamin C and vitamin E) were observed in DMH-induced rats. Supplementation of EA attenuated all these alterations to near normal levels, which indicates the anti-carcinogenic efficacy of EA. This effect was further confirmed by histopathological studies. The results obtained in the present study suggest EA as an effective chemopreventive agent on colon carcinogenesis induced by DMH.

Aberrant crypt foci and AgNORs as putative biomarkers to evaluate the chemopreventive efficacy of pronyl-lysine in rat colon carcinogenesis

Chemoprevention opens new perspectives in the prevention of cancer and other degenerative diseases. Use of target-organ biological models at the histological and genetic levels can markedly facilitate the identification of potential chemopreventive agents. Our aim was to study the chemopreventive efficacy of pronyl-lysine, a key antioxidant present in bread crust by evaluating, the total number of aberrant crypt foci (ACF), their distributions, dysplastic ACF, colonic tumor incidence and the expression of cell proliferation biomarker such as the argyrophilic nucleolar organizing region-associated proteins (AgNORs) in 1,2-dimethylhydrazine (DMH) induced colon cancer in rats. Male Wistar rats were randomized into seven groups, group 1 were control rats, group 2 received pronyl-lysine (2 mg/kg body weight p.o. everyday), rats in groups 3-7 were administered DMH (20 mg/kg body weight) in the groin for 15 weeks. In addition, group 4 (pre-initiation), 5 (initiation), 6 (post-initiation), and 7 (entire period) received pronyl-lysine (2 mg/kg body weight p.o) everyday. At the end of 34 weeks, pronyl-lysine supplementation showed markedly reduced tumor incidence, ACF development and also lowered number of AgNORs. Overall, these findings confirm that pronyl-lysine has a positive beneficial effect against chemically induced colonic preneoplastic progression in rats.

Characteristics of laser-induced autofluorescence spectra in early colorectal carcinoma

AIM: To analyze the characteristics of laser-induced autofluorescence spectra in early colorectal carcinoma.

METHODS: An animal model of colorectal carcinoma was established by injecting DMH in abdominal cavity of Sprague-Dawley rats. Samples were collected from normal, early-stage and advanced carcinoma tissues, respectively. The characteristics of their laser-induced autofluorescence spectra were analyzed.

RESULTS: A total of 226 samples were collected, including 64 normal colorectal tissue samples, 78 early-stage and 84 advanced colorectal carcinoma tissue samples. Spectra peaks were observed at about 460 nm and 505 nm in different groups. The wavelength at 460 nm in normal tissue samples differed significantly from those in early stage and advanced colorectal cancer tissue samples (457.66 ± 3.28, 467.87 ± 7.71, 468.60 ± 4.53, P < 0.05). Spectra peaks were found at 635 nm in 73% advanced colorectal carcinoma tissue samples and 69% early-stage colorectal carcinoma tissue samples, but not in normal colorectal tissue samples. The mean wavelength at 460 nm was longer in normal colorectal tissue samples than in early stage and advanced colorectal carcinoma tissue samples (457.66 ± 3.28 vs 467.87 ± 7.71, 468.60 ± 4.53, P < 0.05). The values of I635/I460 and I635/I600 in early-stage (1.9507 ± 1.1460, 0.4215 ± 0.2582) and advanced carcinoma tissue samples (2.1368 ± 1.4721, 0.4482 ± 0.2309) were higher than those in normal colorectal tissue samples (0.7494 ± 0.1077, 0.1416 ± 0.0439, P < 0.05).

CONCLUSION: The characteristics of laser-induced autofluorescence spectra are different in normal colorectal tissue, early-stage and advanced colorectal carcinoma tissue, and can be used to diagnose early-stage colorectal carcinoma.

Modulatory influence of dietary resveratrol during different phases of 1,2-dimethylhydrazine induced mucosal lipid-peroxidation, antioxidant status and aberrant crypt foci development in rat colon carcinogenesis

To shed light on the association of lipid peroxidation and antioxidant status with the development of aberrant crypt foci (ACF), we studied the modulatory influence of resveratrol, supplemented in three dietary regimens (initiation, post-initiation and entire period) on 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. Rats were administered DMH (20 mg/kg body weight, s.c.) for 15 weeks and were supplemented with resveratrol (8 mg/kg body weight, p.o. everyday) in three dietary regimens. Intestines and colons were analyzed for the levels of diene conjugates (DC), lipid hydroperoxides (LOOHs) and thiobarbituric acid reactive substances (TBARS). Enzymic antioxidants (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPX; glutathione S-transferase, GST; and glutathione reductase, GR) and non-enzymic reserve (reduced glutathione, GSH; ascorbate; and alpha-tocopherol) were also assessed in the intestine and colon. Unsupplemented DMH exposed rats showed significantly decreased levels/activities of tissue DC, LOOHs, TBARS, SOD, CAT, GSH, GR and significantly elevated (P<0.05) GPX, GST, alpha-tocopherol and ascorbate as compared to control rats. Resveratrol supplementation during the entire period of the study resulted in significant (P<0.01) modulation of lipid peroxidation markers and antioxidants status, which were paralleled with ACF suppression, as compared to DMH-alone treated rats. These results indicate that resveratrol effectively inhibits DMH-induced ACF and colonic tumor development.

Effects of STZ-induced diabetes and its treatment with vanadyl sulphate on cyclosporine A-induced nephrotoxicity in rats

The aim of this study was to analyze the effect of streptozotocin (STZ)-induced diabetic state and the insulin-like acting, vanadyl sulphate (VS) on cyclosporine A (CyA) related nephrotoxicity in rats. Male Wistar rats were divided into six groups, of 12 animals each: The control, diabetic rats and diabetic rats whose drinking VS in the drinking water in a concentration of 1 mg/ml. Another three similarly treated groups were injected intra-peritoneally (ip) with CyA in a dose of 25 mg/kg/day for ten doses, 10 days after diabetic induction by using a single dose of STZ of 65 mg/kg. Rats were sacrificed 48 h after the last CyA dose and serum as well as kidneys were isolated and analyzed. Treatment with CyA to control normoglycemic rats resulted in significant increases in kidney weight, serum creatinine, urea nitrogen, cholesterol and triglycerides (TG) levels. Also, the kidney tissue of CyA-treated control animals showed significant increases in total nitrate/nitrite (NO(x)) concentration and malondialdehyde (MDA) production level as well as depletion of glutathione (GSH) content and glutathione peroxidase (GSH-P(x)) activity level. Histopathologic evaluation of CyA-treated control rats revealed tubular atrophy, hyaline casts and focal tubular necrosis. However, treatment of diabetic rats with CyA showed significant reduction in serum creatinine and elevation in TG level as well as reductions in the kidney NO(x) concentration and MDA production level and increase in GSH concentration compared to CyA-treated control rats. Moreover, histopathology of the kidney of CyA-treated diabetics showed typical changes of the diabetic controls revealing glomerular hypertrophy and tubular dilation. On the other hand, treatment with CyA to those diabetic animals administered VS in the drinking water resulted in exacerbation of renal dysfunction, manifested by significant increases in serum indices of nephrotoxicity, cholesterol, TG and bilirubin levels. Also, VS administration to CyA-treated diabetics showed significant increase in kidney NO(x) concentration compared to those CyA-treated diabetics drinking plain tap water, and to a level significantly lower than those CyA-treated controls. Histopathologically, kidney of CyA/VS-treated diabetic showed marked CyA related changes. In conclusion, STZ-induced diabetes might provide partial protection against CyA-induced renal dysfunction. Also, treatment of hyperglycemia with VS might exacerbate CyA related nephrotoxicity.

Vanadium inhibits placental glutathione S-transferase (GST-P) positive foci in 1,2-dimethyl hydrazine induced rat colon carcinogenesis

Vanadium (V) has recently been found to possess potent anti-neoplastic activity in rat colon carcinogenesis. In the present study attempts have been made to investigate the expression of the number and area of aberrant crypt foci positive for placental glutathione S-transferase (GST-P) during 1,2-dimethyl hydrazine (DMH)-induced rat colon carcinogenesis. Male Sprague Dawley rats were randomly divided into four groups. Rats in group A were designed as normal controls. Group B animals received DMH once a week (20 mg/kg body wt.) intraperitoneally for 16 weeks. Group C rats received the same treatment of DMH as in group B, along with 0.5-ppm vanadium as ammonium monovanadate ad libitum in drinking water throughout the experiment. Vanadium alone was given to Group D rats without any DMH injection. The expression of the number and the area of aberrant crypt foci (ACF) positive for GST-P was maximum in DMH-treated group. Vanadium-treated rats significantly reduced (P < 0.001) the expression of GST-P positive ACF cells (by 71.13%) for the entire period of the study. Moreover the histopathological examination also showed that vanadium action could minimize the aberrant crypt foci (P < 0.001). Furthermore, vanadium supplementation also elevated SOD activities in both liver and colon (P < 0.01, P < 0.02 and P < 0.01, P < 0.02 respectively) when compared to their carcinogen counterparts. Our results confirm that vanadium is particularly effective in limiting the action of the carcinogen, thereby establishing its anticarcinogenicity in chemically induced rat colon carcinogenesis.