Gastric cancer(GC), one of the most common malignancies worldwide, seriously threatens human health due to its high morbidity and mortality. Precancerous lesion of gastric cancer(PLGC) is a critical stage for preventing the occurrence of gastric cancer, and PLGC therapy has frequently been investigated in clinical research. Exploring the proper animal modeling methods is necessary since animal experiment acts as the main avenue of the research on GC treatment. At present, N-methyl-N'-nitro-N-nitroso-guanidine(MNNG) serves as a common chemical inducer for the rat model of GC and PLGC. In this study, MNNG-based methods for modeling PLGC rats in related papers were summarized, and the applications and effects of these methods were demonstrated by examples. Additionally, the advantages, disadvantages, and precautions of various modeling methods were briefly reviewed, and the experience of this research group in exploring modeling methods was shared. This study is expected to provide a reference for the establishment of MNNG-induced PLGC animal model, and a model support for the following studies on PLGC.
Animals ; Gastric Mucosa ; Methylnitronitrosoguanidine/toxicity* ; Precancerous Conditions/chemically induced* ; Rats ; Stomach Neoplasms/drug therapy*

OBJECTIVE: To establish a SD rat model of vulvar squamous intraepithelial lesions. METHODS: Seventy female SD rats were randomized into 4 groups, namely the blank control group (=10), mechanical irritation group (=10), acetone solution group (=10), and mechanical irritation with DMBA acetone solution group (=40, model group), and the corresponding treatments were administered 3 times a week for 14 weeks. The changes of the vulvar skin of the rats were observed regularly until the 18th week. The expression of mutant p53 (mtp53) and vascular endothelial growth factor (VEGF) proteins were detected using immunohistochemistry and Western blotting, and the expressions of mtp53 and VEGF mRNA were detected with qRT- PCR in the blank control group and model group. RESULTS: No significant differences were found in the morphological or histopathological changes of the skin among the blank control group, mechanical irritation group and acetone solution group. In the model group, low-grade squamous intraepithelial lesions (LSIL) occurred in 28 rats (70%) and high-grade squamous intraepithelial lesions (HSIL) in 11 rats (27.5%) at 14 weeks, with a success rate of 97.5% in inducing vulvar squamous intraepithelial lesions. Compared with the blank control group, the rats in the model group showed significantly increased expressions of mtp53 and VEGF at both the protein level ( < 0.05) and the mRNA level ( < 0.05). CONCLUSIONS DMBA in acetone solution combined with mechanical irritation can induce vulvar squamous intraepithelial lesions in female SD rats.
9,10-Dimethyl-1,2-benzanthracene ; Acetone ; Animals ; Blotting, Western ; Carcinogens ; Disease Models, Animal ; Female ; Friction ; Immunohistochemistry ; Precancerous Conditions ; chemically induced ; metabolism ; pathology ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Skin ; pathology ; Solvents ; Tumor Suppressor Protein p53 ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism ; Vulvar Neoplasms ; chemically induced ; metabolism ; pathology

OBJECTIVETo investigate the changes of miR-155 and its target genes in colitis-associated carcinogenesis.

METHODSColitis-associated colon cancer was induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) in C57BL/6 mice. Mice of three different stages during the development of colon cancer were obtained, named AD1, AD2 and AD3, respectively. A control group of mice without any treatment and a DSS only group representing chronic inflammation without cancer were set up as well. Colon tissue was collected and expression of miR-155 in the colon tissues was measured by real-time fluorescent quantitative PCR. TargetScan and PicTar were used to predict potential target genes of miR-155, which were then preliminarily screened with our gene expression microarray database of AOM-DSS mouse model. Regular PCR was used to confirm the changes of the expression of these potential target genes in AOM-DSS mouse model.

RESULTSColitis-associated colon cancer was effectively induced by azoxymethane and dextran sulfate sodium in C57BL/6 mice. Histological examination revealed that the evolution process was sequentially from normal, mild dysplasia, moderate dysplasia, and severe dysplasia to adenocarcinoma in the AOM-DSS mouse model. The level of miR-155 was gradually elevated with the formation of colitis-associated colon cancer. There was no significant difference between the levels of miR-155 expression in the DSS group (0.005 6 ± 0.003 7) and control group (0.012 0 ± 0.005 1) (P > 0.05), but the level of miR-155 in the AD3 group (0.054 4 ± 0.027 0) was significantly higher than that of the DSS group (0.005 6 ± 0.003 7)(P < 0.01). No significant change of miR-155 expression was found in the DSS only group. The relative expression levels of miR-155 in the control group, DSS only group and AD3 group were 0.012 0 ± 0.005 1, 0.005 6 ± 0.003 7, 0.054 4 ± 0.027 0, respectively. Data analysis with the gene expression microarray showed that Tle4, Kcna1, Itk, Bcorl1, Cacna1c, Rspo2 and Foxo3 were potential target genes of miR-155 in the AOM-DSS mouse model. Changes of Kcna1 and Cacna1c in the AOM-DSS mouse model were validated to be consistent with the changes obtained with the gene expression microarray.

CONCLUSIONThe up-regulation of miR-155 is related to colitis-associated carcinogenesis, but is irrelevant to chronic inflammation in the mouse model.

Adenocarcinoma ; chemically induced ; genetics ; metabolism ; Animals ; Azoxymethane ; toxicity ; Carcinogens ; toxicity ; Cocarcinogenesis ; Colitis ; chemically induced ; genetics ; metabolism ; Colon ; metabolism ; Colonic Neoplasms ; chemically induced ; genetics ; metabolism ; Dextran Sulfate ; toxicity ; Gene Expression Profiling ; Male ; Mice ; Mice, Inbred C57BL ; MicroRNAs ; metabolism ; Precancerous Conditions ; chemically induced ; genetics ; metabolism ; Up-Regulation

OBJECTIVETo explore the effect of Yanghe Huayan Decoction (YHD, a representative recipe for warming yang mass dissipating) in inhibiting precancerosis of breast cancer (PBC) and on the protein and mRNA expression of ki67.

METHODSThe PBC rat model was established by dimethylbenzanthracene (DMBA), and 9 weeks later rats were randomly divided into the blank control group, the model group, the YHD group, the Sanjie Huatan Decoction group (SHD), the Pingxiao Tablet group (PT), and the tamoxifen group. Rats in the model group were administered with water by gastrogavage. Rats in the YHD group received YHD (deglued antler powder 12 g, prepared rhizome of rehmannia 9 g, cassia bark 6 g, white mustard seed 3 g, zedoary root 12 g, appendiculate cremastra pseudobulb 15 g, chekiang fritillary bulb 9 g, licorice root 6 g) at the daily dose of 7.2 g/kg by gastrogavage. Rats in the SHD group received SHD (oldenlandia diffusa 15 g, Scutellaria Barbata 15 g, Trichosanthes Kirilowii 15 g, pinellia 9 g) at the daily dose of 5.4 g/kg by gastrogavage. Rats in the PT group received PT at the daily dose of 144 mg/kg by gastrogavage. Those in the tamoxifen group received tamoxifen at the daily dose of 4 mg/kg by gastrogavage. Pathomorphological changes of the breast tissue were observed by HE staining. The positive rate and the gray value of ki67 expression were detected by immunohistochemical assay. And the expression of ki67 mRNA was detected by q-PCR.

RESULTSCompared with the model group, the general hyperplasia and the occurrence rate of precancerous lesion were higher and the occurrence rate of invasive carcinoma was lower in each treatment group (P < 0.05). Except the SHD group, the intensity of ki67 grey value increased in each treatment group (P < 0.05, P < 0.01). Except the PT group, the positive rate of ki67 and mRNA expression of ki67 increased in the rest treatment groups (P < 0.05, P < 0.01). Compared with the YHD group, there was no statistical difference in the occurrence rate of infiltration or the occurrence rate of precancerous lesion (P > 0.05). The positive rate of ki67 expression and mRNA expression of ki67 increased in the PT group, showing statistical difference (P < 0.05).

CONCLUSIONSYHD could partially inhibit and reverse canceration of breast cancer. It also could inhibit ki67 protein and mRNA expression. Its effect was similar to tamoxifen and superior to PT. So it was suitable for prevention and treatment of precancerous lesion of breast cancer.

Animals ; Disease Models, Animal ; Drugs, Chinese Herbal ; therapeutic use ; Female ; Ki-67 Antigen ; metabolism ; Mammary Neoplasms, Experimental ; chemically induced ; drug therapy ; metabolism ; Precancerous Conditions ; drug therapy ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo screen the differentially expressed proteins especially at the precancerous stage of diethylnitrosamine (DEN) induced hepatocarcinogenesis by comparative proteome research.

METHODSRats were divided into normal and DEN groups and sacrificed periodically. The liver samples were stained with gamma-glutamyl transpeptidase (GGT) and HE to distinguish the preneoplastic lesion (pre-HCC) from the normal and HCC tissues. The two-dimensional electrophoresis (2-DE) and mass spectrometry (MALDI-TOF-MS/MS) were then applied to analyze the differentially expressed protein between pre-HCC and normal tissues, pre-HCC and HCC, as well as HCC and normal tissues. A few of the candidate proteins such as laminin receptor 1 (67LR) and agmatinase were validated by Western blot and RT-PCR.

RESULTSTotally, there were 82 proteins that differentially expressed two fold or more in one kind of tissues sample than the other, 47 of which occurred in the pre-HCC tissues. Eight proteins including 67LR were consistently up-regulated from normal tissue to pre-HCC and then to HCC tissues, while 22 proteins including agmatinase showed progressively down-regulated in these tissues samples.

CONCLUSIONThe protein expression profiles are different during the process of hepatocarcinogenesis. Further study on the differentially expressed protein, especially these upregulated in the precancerous stage such as 67LR and agmatinase, might contribute to prevention and early diagnosis of human HCC.

Animals ; Blotting, Western ; Carcinoma, Hepatocellular ; chemically induced ; metabolism ; pathology ; Diethylnitrosamine ; Liver ; metabolism ; pathology ; Liver Neoplasms, Experimental ; chemically induced ; metabolism ; pathology ; Male ; Neoplasm Proteins ; metabolism ; Precancerous Conditions ; metabolism ; pathology ; Proteins ; metabolism ; Proteome ; Rats ; Rats, Wistar ; Receptors, Laminin ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Ureohydrolases ; metabolism ; gamma-Glutamyltransferase

OBJECTIVETo investigate the enhancive effect of N,N'-dinitrosopiperazine (DNP) on induced carcinogenesis in nasal and/or nasopharyngeal epithelia among TgN(p53mt-LMP1)/HT transgenic mice to examine the underlying mechanism for the development of nasopharyngeal carcinoma (NPC).

METHODSTgN(p53mt-LMP1)/HT transgenic mice and the same strain of C(57)BL/6J wild-type mice both at the age of 5 months were randomly divided into 2 groups in parallel, respectively, i.e., TgN(p53mt-LMP1)/HT cancerous lesion-inducing group (TI), TgN(p53mt-LMP1)/HT control group (TC), C57BL/6J cancerous lesion-inducing group (CI), and C57BL/6J control group (CC). TI and CI mice were treated only with DNP for 16 weeks, twice each week, while TC and CC mice were given the same volume of saline as controls. At the end of treatment, animals were sacrificed to collect epithelial tissue samples from nasal cavity and nasopharynx for pathohistological evaluation by haematoxylin and eosin (HE) staining and for determination on the expression of TRAF2, c-Jun, and p16 by immunohistochemistry.

RESULTSAtypical hyperplasia was more significant in the samples of TI than in those of TC, CI, and CC, with the rates of lesions being 90%, 10%, 0, and 0 (P<0.01) respectively, though DNP was used alone in a much shortened inducing period at less dosage and without the use of carcinogenic promoter 12-O-tetradecanoylphorbol-13-acetate as usual. The expressions of tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) and c-Jun in these samples were significantly up-regulated in TI (P<0.01), while the expression of p16 was significantly lower in TI than in the other groups (P<0.01).

CONCLUSIONTgN(p53mt-LMP1)/HT mice hold inherited constitutional defect in immune surveillance function, which can be aggravated by environmental carcinogens, such as DNP used even though in a much less strength. The enhanced carcinogenesis-inducing effect of DNP on TgN(p53mt-LMP1)/HT mice should be closely associated with abnormal signaling of activator protein-1 (AP-1) pathway, especially up-regulated expressions of TRAF2 and c-Jun, and down-regulated expression of p16.

Animals ; Epithelial Cells ; drug effects ; metabolism ; pathology ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Mice ; Mice, Transgenic ; Mutation ; genetics ; Nasopharyngeal Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Nitrosamines ; pharmacology ; Nose Neoplasms ; chemically induced ; genetics ; metabolism ; pathology ; Precancerous Conditions ; chemically induced ; genetics ; pathology ; TNF Receptor-Associated Factor 2 ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; Viral Matrix Proteins ; genetics ; metabolism

OBJECTIVETo investigate the carcinogenic and mutagenic mechanism of bitumen fume.

METHODSThe experimental mice were forced to inhale the bitumen fume at different exposure level (55 mg/m(3), 165 mg/m(3)) and in different time (30 days, 60 days). The pathological changes of the lung tissue in mice were observed with H.E staining. The content of the DNA in the lung tissue of mice and the cell circles were determined with flow cytometry.

RESULTSThe lesion of the lung tissue in mice comprised the atypical hyperplasia of different levels and the carcinoma in situ with the increase of the containment time and dosage; the cycle index was changed: the number of the G 1 phase cells was decreased, the S phase was retarded, the cells entering the G 2/S phase were decreased, the cell proliferation index (P I) was increased and the heteroploid DNA index (DI) was increased (P < 0.05). The cell index in the 55 mg/m(3) group and the 165 mg/m(3) group was higher than that in the control group when the containment time was same. The heteroploid DNA index (DI) in the 55 mg/m(3) group was significantly higher than that in the 165 mg/m(3) group (P < 0.05 or P < 0.01). When the containment dosage was same, the DI in the 60 days treatment group (1.16 +/- 1.51 x 10(-2), 1.20 +/- 2.3 x 10(-2)) was all significantly higher than those in the 30 days treatment group (1.14 +/- 8.8 x 10(-2), 1.16 +/- 1.47 x 10(-2)) (P < 0.05).

CONCLUSIONThe precancerous lesion in the lung tissue of the mice induced by the bitumen fume may be related with the changes of the cell cycle.

Animals ; Carcinogens ; toxicity ; Cell Cycle ; drug effects ; DNA ; analysis ; Dose-Response Relationship, Drug ; Female ; Flow Cytometry ; Hydrocarbons ; toxicity ; Lung ; drug effects ; pathology ; Male ; Mice ; Mice, Inbred Strains ; Precancerous Conditions ; chemically induced ; pathology

OBJECTIVETo explore the hepatic injury induced by CCl4in SD rat.

METHOD40 SD rats were allocated to male and female group, consisting of 20 animals/sex/group. SD rats were given at 2 mL x kg(-1) of 10% CCl4 through celiac injection per 3 day for 12 days. All rats were killed by anaesthesia of ethyl ether and bleeding through abdominal aorta at 12th day. Liver tissue was fixed in 10% neutral formalin, embedded in paraffin, cut at a nominal thickness of 3 microm, stained with hematoxylin and eosin ( H&E) , evaluated at by microscopic examination.

RESULT19 cases with local necrosis, 8 cases with fatty degeneration, 9 cases with cystic degeneration and 2 cases with fibrosis were seen in group male. 20 cases with local necrosis, 9 cases with fatty cases degeneration, 1 case with cystic degeneration and 1 case with fibrosis were seen in group female. The incidence of cystic degeneration in male group was found significantly higher than that in female group (P < 0. 05) , but the incidence of other lesions was no significant difference between male and female group.

CONCLUSIONCCl4 induces local necrosis , fatty degeneration, fibrosis and cystic degeneration in SD rat. The incidences of local necrosis , fatty degeneration and fibrosis were no significantly difference between male and female rat, but the incidence of cystic degeneration in male rats was significant higher than that in female rats.

Animals ; Carbon Tetrachloride ; Chemical and Drug Induced Liver Injury ; Cysts ; chemically induced ; pathology ; Disease Models, Animal ; Female ; Liver ; pathology ; Liver Cirrhosis ; chemically induced ; pathology ; Liver Diseases ; pathology ; Liver Neoplasms ; chemically induced ; pathology ; Male ; Precancerous Conditions ; chemically induced ; pathology ; Rats ; Rats, Sprague-Dawley ; Sex Factors

OBJECTIVETo further explore the carcinogenic activity of Sterigmatocystin (ST) and the possible synergistic carcinogenic effect of deoxynivalenol (DON) in NIH mice.

METHODSNIH mice were randomly divided into 6 groups, 30 in each. Five groups of mice were given by gastric intubation ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg respectively, 3 times a week for 24 weeks. The remaining group of mice was given normal saline accordingly, serving as control. All mice were fed with HPLC-confirmed mycotoxin-free food, analysis. The mice were killed and pathologically examined at 58th and 74th weeks.

RESULTSNo pathological changes were found in the control group of mice. Adenocarcinoma of lung was observed in 25.0%, 41.7%, 62.5%, 69.2% and 37.5% of mice given ST 3 microg/kg, ST 30 microg/kg, ST 3 microg/kg + DON 1.5 microg/kg, ST 30 microg/kg + DON 1.5 microg/kg and DON 1.5 microg/kg, respectively. In addition, dysplasia of glandular stomach was detected in 50.0%, 58.3%, 37.5%, 53.8% and 25.0% of mice similarly treated.

CONCLUSIONOral administration of ST or DON can induce adenocarcinoma in lung and dysplasia of glandular stomach in NIH mice. There is synergistic carcinogenic effect when both ST and DON are given.

Adenocarcinoma ; chemically induced ; pathology ; Animals ; Female ; Gastric Mucosa ; pathology ; Lung Neoplasms ; chemically induced ; pathology ; Male ; Mice ; Precancerous Conditions ; chemically induced ; pathology ; Sterigmatocystin ; toxicity ; Trichothecenes ; toxicity

Animals ; Apoptosis ; Azoxymethane ; Colorectal Neoplasms ; chemically induced ; metabolism ; pathology ; Cytoskeletal Proteins ; metabolism ; Precancerous Conditions ; chemically induced ; metabolism ; pathology ; Rats ; Rats, Inbred F344 ; Trans-Activators ; metabolism ; beta Catenin