No abstract available.
1,2-Dimethylhydrazine* ; Carcinogenesis* ; Vitamins*

BACKGROUND/AIMS: The purpose of this study was to investigate the malignant potential of aberrant crypt foci (ACF) by measuring the multiplicity of crypts and lectin expression in the early and late stages of 1,2-dimethylhydrazine (DMH)-induced colon carcinogenesis. METHODS: Six-week-old Wistar rats were injected subcutaneously with DMH for 27 weeks. We classified ACF according to the number of crypts per ACF as a few crypts (< or =3 crypts, FC ACF) or numerous crypts (> or =4 crypts, NC ACF). Immunohistochemistry was used to evaluate lectin expression. RESULTS: In the early stage, FC ACF (590/1,902, 31.0%) occurred more frequently than NC ACF (35/449, 7.8%); whereas in the late stage, NC ACF (176/449, 39.2%) occurred more frequently than FC ACF (324/1,902, 17.0%). The number of ACF peaked at 15 to 20 weeks. The ratio of NC/FC ACF increased gradually during carcinogenesis. The expression of both UEA1 and PNA was higher in NC ACF than FC ACF. Lectin expression increased in the late stage compared with the early stage. CONCLUSIONS: The expression of lectin was higher in NC ACF and ACF in the late stage. Therefore, ACF with higher multiplicities in the late stage may have more malignant potential in DMH-induced colon carcinogenesis.
1,2-Dimethylhydrazine ; Aberrant Crypt Foci ; Animals ; Colon ; Dimenhydrinate ; Immunohistochemistry ; Peanut Agglutinin ; Rats ; Rats, Wistar

PURPOSE: Protein tyrosine kinase(PTK), protein kinase C(PKC), oxidase, as a mediator, have been known to take a role in signal transduction pathway of angiogenesis. The authors confirmed that PKC is the most noticeable mediator for abnormal proliferation of vascular endothelial cells through in vitro study model using the inhibitors, targeting the formation of three co-enzymes. In this study, we would investigate which isoform of PKC play an important role in abnormal angiogenesis of vascular endothelial cell. METHODS: In 96 well plates, 10(4) HUVECs(human umbilical vein endothelial cells) were evenly distributed. Two groups were established; the control group without administration of DMH(1,2-dimethylhydrazine) and the DMH group with administration of 7.5x10(-9)M DMH. RNA was extracted from vascular endothelial cell of each group and expression of the PKC isoform was analyzed by RT-PCR(reverse transcriptase-polymerase chain reaction) method. RESULTS: RT-PCR analysis showed that PKCalpha, -betaI, -betaII, -eta, -micron and -zeta were expressed in vascular endothelial cells of each group. DMH incresed the expression of PKCalpha and PKCmicron, and decreased PKCbetaI, PKCbetaII expression dominantly. CONCLUSION: Based on the result of this study, it was suggested that PKCalpha and PKCmicron may have significant role in abnormal proliferation of vascular endothelial cell.
1,2-Dimethylhydrazine* ; Cell Proliferation ; Dimenhydrinate ; Endothelial Cells* ; Oxidoreductases ; Protein Kinase C* ; Protein Kinases* ; RNA ; Signal Transduction ; Tyrosine ; Umbilical Veins

OBJECTIVETo study the pathogenic and tumorigenic effect of 1,2-dimethylhydrazine (DMH) on the colon and ovaries of mice.

METHODSSixty ICR female mice were randomly divided into groups A and B for intraperitoneal injection of DMH (20 mg/kg) and saline (control) once a week for 24 weeks, respectively. The mice were sacrificed at 12, 16, 20, 24, 28 and 32 weeks after the first DMH injection for pathological examination of the colon and ovaries.

RESULTSIn group A, colorectal adenomas were found in 7, colorectal adenocarcinomas in 5, and hemorrhagic lesions of the ovaries with chronic inflammatory in 21 mice. Choriocarcinoma in the ovaries were detected in one mouse at 28 weeks and in another at 32 weeks. No obvious pathological changes were found in group B following the injections.

CONCLUSIONIntraperitoneal injection of DMH may induce colon tumors and ovarian diseases in mice.

1,2-Dimethylhydrazine ; toxicity ; Animals ; Colon ; drug effects ; pathology ; Colonic Neoplasms ; chemically induced ; Female ; Mice ; Mice, Inbred ICR ; Ovarian Diseases ; chemically induced ; Ovary ; drug effects ; pathology

The inhibitory effects of ginseng on the development of 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in the colon were investigated in rats. Male, 6-week-old rats were injected with DMH once a week for 4 weeks. Rats in Groups 1 and 2 were fed diets containing red and white ginseng, rerspectively, at a dose of 1% for 5 weeks, starting one week before the first treatment of DMH. Animals in Groups 3 and 4 received red or white ginseng for 8 weeks starting after DMH treatment. Group 5 served as a carcinogen control group. Numbers of ACF with at least four crypts were significantly reduced in the colon of Group 2 treated with red ginseng combined with DMH. Moreover, rats were injected with DMH 4 times at one-week intervals. They were also fed diets containing 1% red or white ginseng or the control diet throughout 30 days of the experiment. Treatment with red ginseng resulted in a significant decrease of 5- bromo-2'-deoxyuridine labeling indices in colonic crypts comprising ACF. These findings suggest that dietary administration of red ginseng in combination with DMH suppresses colon carcinogenesis in rats, and the inhibition may be associated, in part, with inhibition of cell proliferation, acting on ACF in the colonic mucosa.
1,2-Dimethylhydrazine/adverse effects ; Animal ; Anticarcinogenic Agents/*pharmacology ; Carcinogenicity Tests ; Carcinogens/adverse effects ; Colonic Neoplasms/pathology/*prevention & control ; Male ; *Panax ; Plant Roots ; Precancerous Conditions/pathology/*prevention & control ; Rats ; Rats, Inbred F344

The study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid (CLA) isomers on colon carcinogenesis in 1,2-dimethylhydrazine (DMH)-treated rats by determining the levels of apoptosis, cell proliferation, eicosanoids and 1,2-diacylglycerol (DAG) in colonic mucosa. Sixty male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. BT group (no CLA contained), CLA-C group (cis-9, trans11 isomer contained), and CLA- T group (trans-10, cis-12 isomer contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 0.8% CLA isomers by weight. The experimental diet was fed for 14 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of l80mg per kg body weight. Two CLA isomers (c9t11 and t10c12) significantly increased the relative percentage of apoptosis but reduced cell proliferation in mucosal cell and also the levels of PGE2, TXB2, and DAG in colonic mucosa. However, there was no significant differences in anti-carcinogenic effect between c9t11 isomer and t10c12 isomer. Overall, colon carcinogenesis could be significantly inhibited by CLA isomers by increasing apoptosis and reducing cell proliferation, the levels of eicosanoids and DAG in colonic mucosa.
1,2-Dimethylhydrazine ; Animals ; Anticarcinogenic Agents ; Apoptosis* ; Body Weight ; Carcinogenesis ; Cell Proliferation* ; Colon* ; Colonic Neoplasms ; Diet ; Dimenhydrinate ; Dinoprostone ; Eicosanoids ; Humans ; Injections, Intramuscular ; Linoleic Acid ; Male ; Mucous Membrane* ; Rats* ; Rats, Sprague-Dawley

This study was designed to compare the anti-carcinogenic effect of conjugated linoleic acid isomers on tumor incidence, cell proliferation and the levels of thromboxane (TX)B2, prostaglandin (PG)E2 and 1,2-diacylglycerol (DAG), and the related enzyme expression of cyclooxygenase (COX)-2 and protein kinase C (PKC) in colonic mucosa of 1,2-dimethylhydrazine (DMH)-treated rats. One hundred eight male Sprague Dawley rats were randomly divided into 3 groups depending on the types of CLA isomers, i.e. control group (no CLA contained), c9t11 group (cis-9, trans-11 CLA contained), and t10c12 group (trans-10, cis-12 CLA contained). The experimental diet was composed of protein at 20%, carbohydrate at 56.2%, and fat at 14.5% including 1.0% CLA isomers by weight. The experimental diet was fed for 30 weeks with the initiation of intramuscular injection of DMH, which was injected twice a week for 6 weeks to give total dose of 180 mg per kg body weight. Two CLA isomers (c9, t11; t10, c12) significantly reduced tumor incidence and cell proliferation by reducing the protein expression of COX-2 and PKC, and the level of TXB2, PGE2, and DAG in colonic mucosa. However, there was no significant difference in anti-carcinogenic effect between c9t11-CLA and t10c12-CLA.
1,2-Dimethylhydrazine ; Animals ; Anticarcinogenic Agents ; Body Weight ; Cell Proliferation ; Colon* ; Colonic Neoplasms ; Cyclooxygenase 2* ; Diet ; Dimenhydrinate ; Dinoprostone ; Humans ; Incidence* ; Injections, Intramuscular ; Linoleic Acid* ; Male ; Mucous Membrane* ; Prostaglandin-Endoperoxide Synthases ; Protein Kinase C* ; Protein Kinases* ; Rats* ; Rats, Sprague-Dawley

OBJECTIVETo investigate the anti-colon cancer effects of berberine and possible relationship with cyclooxygenase-2.

METHODWistar rat colon cancer model was induced by 1-2 dimethylhydrazine (DMH) (40 mg x kg(-1), sc) + 1% dextran sodium sulfate solution (DSS) (freely drinking). All rats were randomly divided into 3 groups: Control (DMH + DSS + solvant), meloxicam (Mel) (DMH + DSS + Mel 1.35 mg x kg(-1)), berberine (Ber) (DMH + DSS + Ber 100 mg x kg(-1)). The drugs were given orally once a day for 5 day per week. The body weight, the number of colon ACFs, the incidence and number of colon cancer in rats, as well as the morphological changes of rat colon tissues were evaluated. Human colon cancer lovo cell line was treated by either Ber or Mel in various concentrations (1 10(-6) mol x L(-1), 1 x 10(-5) mol x L(-1), 1 x 10(-4) mol x L(-1), 1 x 10(-3) mol x L(-1)) for 6, 12 and 24 h, respectively, and the cell growth was assayed by MTT method. RT-PCR and western-blot were used to evaluate the mRNA and protein expressions of COX-2 from lovo cells treated with Ber and Mel.

RESULTBer significantly improved the dyscrasia induced by DMH + DSS, the both of body weight and general condition were better than control group. Ber also significantly inhibited ACF and colon cancer incidence in the rats treated by DMH + DSS for 10 weeks or 20 weeks, which was similar to that of Mel. Ber inhibited the proliferation of lovo cells in concentration- and time-dependent manners, and the IC50 values were significantly smaller than that of Mel at 6, 12 and 24 h after lovo cells were treated by either Ber or Mel. Ber also concentration-dependently decreased expressions of COX-2 mRNA and COX-2 protein from lovo cells.

CONCLUSIONBer can inhibit ACF and tumor formation induced by DMH + DSS, and decrease the lovo cell proliferation index. The anti-tumor effects of Ber may involve in an unknown pathway through which the expressions of COX-2 mRNA and protein were inhibited.

1,2-Dimethylhydrazine ; toxicity ; Aberrant Crypt Foci ; prevention & control ; Animals ; Berberine ; therapeutic use ; Body Weight ; drug effects ; Colonic Neoplasms ; enzymology ; prevention & control ; Cyclooxygenase 2 ; genetics ; Dextran Sulfate ; toxicity ; Female ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar

Deregulation of G1 cyclins has been reported in several human and rodent tumors including colon cancer. To investigate the expression pattern of G1 cyclins in 1,2- dimethyl-hydrazine dihydrochloride (DMH)-induced rat colon carcinogenesis, we studied the expression of cyclin D1 and cyclin E by quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis and immunohistochemistry (IHC). The mRNA level of cyclin D1 was increased 1.2-fold in adenocarcinomas but not significantly in adenomas, when compared with normal rat colonic mucosa (p<0.05). The cyclin E mRNA level was increased 2.7-fold in adenomas and 3.3-fold in adenocarcinomas (p<0.05). The PCNA mRNA level was also increased 1.9-fold in adenomas and 1.8-fold in adenocarcinomas (p<0.05). Immunohistochemical staining revealed exclusive nuclear staining of the neoplastic cells for cyclin D1, cyclin E and PCNA. Cyclin D1 expression was detected in 56.3% of the adenomas and in 61.5% of the adenocarcinomas examined, whereas cyclin E expression was detected in 87.5% of the adenomas and in 92.3% of the adenocarcinomas. Overall, cyclin D1, cyclin E and PCNA expression was significantly increased at both the mRNA and protein levels in normal colonic mucosa, adenomas and adenocarcinomas, but there was no significant difference in the degree of expression of these genes in adenomas and adenocarcinomas. Our results indicate that the overexpression of cyclin D1 and cyclin E may play an important role during the multistage process of rat colon carcinogenesis, at a relatively early stage, and may disturb cell-cycle control in benign adenomas, and thereafter, participate in tumor progression.
1,2-Dimethylhydrazine/toxicity ; Adenocarcinoma/*chemically induced/metabolism ; Adenoma/*chemically induced/metabolism ; Animals ; Carcinogens/toxicity ; Cell Cycle/drug effects/physiology ; Colon/metabolism ; Colonic Neoplasms/*chemically induced/metabolism ; Cyclin D1/*biosynthesis/genetics ; Cyclin E/*biosynthesis/genetics ; Gene Expression Regulation, Neoplastic ; Immunohistochemistry ; Male ; Proliferating Cell Nuclear Antigen/biosynthesis/genetics ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction