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Objective: κ-carrageenan is a food stabilizer agent which has an antiproliferative effect, while vitamin D is a prohormone acts on the nuclear receptor and has a cytotoxic against cancer. This study aimed to show the synergistic effect of using topical κ-carrageenan and oral administration of the vitamin D on the 7, 12-dimethylbenz[a] anthracene (DMBA)-induced oral cancer. Material and Methods: fifty four male albino rats were randomly divided into seven groups: Acetonetreated served as control (Group I), vitamin D (5000UI)-treated (Group II), κ-carrageenan (1%)- treated (Group III), DMBA (0.5%)-treated (Group IV), Acetone, κ-carrageenan and DMBA were administered topically on both cheeks and palate, five times weekly for 12 weeks, while the vitamin D was administered orally twice weekly for 12 weeks. Groups V, VI, and VII were animals treated with vitamin D, κ-carrageenan, and both vitamin D and κ-carrageenan for 8 weeks after induction of oral cancer. At the end of the study, blood samples were obtained by cardiac puncture for determination of TNF-α and EGFR. Results: In the groups III and IV, serum EGFR showed significant low levels compared with Group I. In the Group VII, serum EGFR showed a significantly (p=0.014) low level compared with Group IV (614.3±69.7 pg/ml versus 882.4±45.6 pg/ml, respectively). Higher percentages of high levels of TNF-α were observed in the Groups VI and VII, while a lower percentage of EGFR was observed in the Group VI. Conclusion: both κ-carrageenan and vitamin D have antiproliferative effect against DMBAinducing oral cancer by increasing the levels of TNF-α and suppressing the signaling pathway of EGFR. Concomitant using κ-carrageenan and vitamin D reduces the antiproliferative effect of each other.(AU)
Objetivo: κ-carragenina é um agente estabilizador de alimentos que tem efeito um antiproliferativo, enquanto a vitamina D é um pró-hormônio que atua sobre o receptor nuclear e possui efeito citotóxico contra o câncer. Este estudo teve como objetivo mostrar o efeito sinérgico do uso de κ-carragenina tópica e administração oral da vitamina D no câncer de boca induzido por 7, 12-dimetilbenz[a]antraceno (DMBA). Material e Métodos: cinquenta e quatro ratos albinos machos foram divididos aleatoriamente em sete grupos: tratado com acetona como controle (Grupo I), tratado com vitamina D (5000UI) (grupo II), tratado com κ-carragenina (1%) (grupo III), DMBA (0,5%) tratado (Grupo IV), acetona, κ-carragenina e DMBA foram administrados topicamente nas bochechas e no palato, cinco vezes por semana durante 12 semanas, enquanto a vitamina D foi administrada por via oral duas vezes por semana durante 12 semanas. Os grupos V, VI e VII foram animais tratados com vitamina D, κ-carragenina e No final do estudo, foram obtidas amostras de sangue por punção cardíaca para determinação do TNF-α e EGFR. Resultados: Nos grupos III e IV, o EGFR sérico mostrou níveis baixos significativos em comparação com o Grupo I. No grupo VII, o EGFR sérico mostrou um nível significativamente baixo (p = 0,014) em comparação com o Grupo IV (614,3 ± 69,7 pg / ml versus 882,4 ± 45,6 pg / ml, respectivamente). Maiores porcentagens de TNF-α foram observadas nos Grupos VI e VII, enquanto uma menor porcentagem de EGFR foi observada no Grupo VI. Conclusão: Tanto a κ-carragenina quanto a vitamina D têm efeito antiproliferativo contra o câncer de boca induzido por DMBA aumentando os níveis de TNF-α e suprimindo a via de sinalização do EGFR. O uso concomitante de κ-carragenina e a vitamina D reduz o efeito antiproliferativo um do outro (AU)
Subject(s)
Animals , Rats , Vitamin D , Mouth Neoplasms , Tumor Necrosis Factor-alpha , 9,10-Dimethyl-1,2-benzanthracene , ErbB ReceptorsABSTRACT
Objective@#To explore the feasibility of 7, 12-dimethylbenz[a] anthracene (DMBA) induced tree shrew breast cancer model, and compare the effects of two administration modes by gavage and mammary gland injection.@*Methods@#A total of 40 tree shrews were randomly divided into two groups (20 animals per group): DMBA gavage group and mammary gland injection group. DMBA was dissolved in edible vegetable oil. For gavage group, tree shrews were administered with DMBA solutions (15 mg/kg) by gavage once a day. For mammary gland injection group, DMBA solution (10 mg/kg) was injected into the mammary fat pad of tree shrews, and the injection was performed for a total of 3 times. From the first administration of DMBA, medroxyprogesterone acetate (MPA, 100 mg/kg) was intramuscularly injected into the muscles of the lateral thighs of tree shrews at the same time, for a total of 5 times. The tumorigenesis and survival of tree shrews were monitored. The tumor histological morphology was observed by HE staining. The expression of estrogen receptor (ER), progesterone receptor (PR), cytokeratin5/6 (CK5/6) and human epidermal factor receptor-2 (HER-2) was detected by immunohistochemical staining.@*Results@#In the gavage group, there were 10 deaths, and 4 tree shrews developed mammary tumors with 20.0% (4/20) tumor formation rate. The success rate of mammary cancer modeling was 10.0% (2/20), and the tumor formation time was 197.3±15.1 days. In the mammary gland injection group, there were 8 tree shrews died, and 9 tree shrews formed tumors with 45.0% (9/20) tumor formation rate. The success rate of mammary cancer modeling was 40.0% (8/20), and the tumor formation time was 71.8±19.0 days. There was no significant difference in mortality and tumor formation rate (P>0.05) between the two groups (all P>0.05). However, in the mammary gland injection group, the success rate of mammary cancer modeling was significantly higher than that in the gavage group (P<0.05), whereas the tumor formation time was markedly shorter than that in the gavage group (P<0.01). The pathological types in the gavage group included ductal hyperplasia, intraductal papilloma and ductal carcinoma in situ, while those in the breast injection group included intraductal papilloma and ductal carcinoma in situ. In both groups, immunohistochemical staining showed the negative expression of HER-2 but positive expression of ER, PR and CK5/6 with varying degrees.@*Conclusion@#Both the DMBA gavage and mammary gland injection can successfully establish the tree shrew breast cancer model, and the modeling effect of mammary gland injection is better than gavage.
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<p><b>OBJECTIVE</b>To investigate the impact of dampness-heat (DH) on the development of mammary tumors in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rats.</p><p><b>METHODS</b>Forty rats were randomly divided into 3 groups in a randomized block design, including the control group (n=13), DMBA group (n=14), and DMBA plus DH group (n=13). Rats in the DMBA group and DMBA plus DH group were intragastrically administrated with DMBA (100 mg/kg) for twice, once per week, while rats in the control group were treated with equivalent volumes of sesame oil. After DMBA administration, rats in the DMBA plus DH group were exposed to a simulated climate chamber with ambient temperature (33.0±0.5°C) and humidity (90%±5%) for 8 weeks, 8 h per day. The body weight, time of tumor formation, and number of tumors were measured weekly to calculate tumor incidence, average latency period, average number of tumors, and average tumor weight. At the end of the experiment, the levels of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinases 1 (TIMP-1) in serum, and the contents of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β in serum and tumor tissue were measured, respectively. Some tumor tissues were processed for hematoxylin-eosin staining to determine the histopathological changes.</p><p><b>RESULTS</b>Compared with DMBA, DMBA plus DH significantly increased the average number of tumors, average tumor weight, levels of serum MMP-9, TIMP-1, TNF-α and IL-1β, and contents of tumor tissue TNF-α and IL-1β (P<0.05 or P<0.01).</p><p><b>CONCLUSION</b>DH could accelerate the development of mammary tumors through increasing the expressions of MMP-9, TIMP-1, TNF-α and IL-1β in DMBA-induced rats.</p>
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Objective To establish a mouse model of cutaneous squamous cell carcinoma induced by 7,12-dimethylbenz(a)anthracene (7,12-DMBA)/croton oil and narrow-band ultraviolet B (NB-UVB) irradiation.Methods A total of fifty 6-8-week old BALB/c mice (male:female 1:1) were randomly divided into three experimental groups.The group A was treated with chemical carcinogens alone, group B was treated with NB-UVB alone, and group C was treated with chemical carcinogens plus NB-UVB.The general status and skin appearance of mice were observed during the experiment.The survival rate and tumor formation rate of each group was calculated at weeks 5, 10, 15, and 20. Pathological examination was carried out to observe the histological changes of skin lesions.Results Papules measuring≥l mm in diameter began to develop in some mice of the group C at 5 weeks after the first treatment with chemical carcinogens.The tumor formation rates at 20 weeks after treatment were 86.67%, 7.14%, 94.12%in the groups A, B, C, respectively.Pathological examination revealed characteristic changes of squamous cell carcinoma in 13.34%, 0%, 70.59%of the mice in the group A, B, C, respectively.Conclusions Establishment of a mouse model of cutaneous squamous cell carcinoma induced by 7,12-DMBA/croton oil and NB-UVB is a better method than treated with chemical carcinogens alone or NB-UVB alone.This method can increase the tumor formation rate and incidence rate of SCC, and within a shorter period.
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Background: The aim of the current study is to evaluate the anti-tumor activity of saponins isolated from the roots of Momordica cymbalaria (MC) against dimethylbenz[a]anthracene (DMBA) induced rats. Methods: A steroidal saponin MC (SMC) was isolated from MC fenzl and purified by preparative high-performance liquid chromatography. Breast cancer was induced in 50-day-old female Sprague-Dawley rats by injecting DMBA (6 mg/kg intravenous) in three doses on day 50, 54, and 57. The rats were randomized into four groups; control, DMBA, SMC (100 mg/kg), and tamoxifen (6.6 mg/kg) to DMBA breast cancer rats. The tumor size, volume, hormonal, antioxidant, and whole mount parameters were estimated. Results: Mean tumor size and volume, luteinizing hormone, and progesterone with superoxide dismutases, catalase, and glutathione levels increased significantly (p<0.001); serum estradiol, follicle stimulating hormone with lipid peroxidation decreased significantly (p<0.001) in DMBA-induced breast cancer and vice versa in SMC and tamoxifen. Terminal end buds, terminal ducts, alveolar buds, and lobules decreased significantly (p<0.001) in DMBA-induced breast cancer whereas increased significantly in SMC and tamoxifen. Histological necrosis and hemorrhage along with focal desmoplastic reaction in DMBA-induced breast cancer; ductile elongation and hyperplasia of both ducts and alveoli were prominent, with increased secretory activity in SMC group. The results confirmed the chemopreventive effect of SMC and tamoxifen in DMBA-induced breast cancer. Conclusions: The SMC exhibited anti-tumor activity against mammary cancer, which may be due to its anti-estrogenic, antioxidant activity.
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The hepatoprotective potential of aqueous Azadirachta indica leaf extract (AAILE) was assessed against DMBA-induced hepatotoxicity. DMBA (7,12-dimethylbenz[a] anthracene) treatment (40 mg/kg body weight, ip) to male Balb/c mice resulted in the derailment of liver function as revealed by extremely slow clearance of 99mTc-mebrofenin from liver, elevated levels of alkaline phosphatase (ALP) and alanine transaminase (ALT), compared to control group. In addition, elevated micronuclei score and high apoptotic index indicated hepatogenotoxicity in DMBA-treated mice. DMBA treatment also upregulated cytochrome P450 (CYP), cytochrome b5 (Cyt b5) and decreased glutathione-S-transferase activity in hepatic tissue, compared to control group. Enhanced lipid peroxidation (LPO) levels along with decreased reduced glutathione (GSH) level were also observed in DMBA group, compared to control group. AAILE co-treatment (200 mg/kg body weight, po, thrice a week) for 8 weeks followed by DMBA injection showed significant improvement in hepatic status, as revealed by normalization of 99mTc-mebrofenin clearance rate, decreased ALP and ALT levels, reduced genotoxicity in terms of micronuclei score and apoptotic index. Levels of LPO were significantly decreased along with increased hepatic GST and GSH levels in AAILE + DMBA group, compared to DMBA group. However, no significant change was observed in hepatic CYP and Cyt b5 levels, compared to DMBA group. The results indicated that AAILE effectively ameliorated DMBA-induced hepatotoxicity.
Subject(s)
9,10-Dimethyl-1,2-benzanthracene/toxicity , Animals , Azadirachta/chemistry , Cell Division/drug effects , Cytoprotection/drug effects , Liver/cytology , Liver/drug effects , Liver/metabolism , Liver/toxicity , Male , Mice , Mice, Inbred BALB C , Micronucleus Tests , Oxidative Stress , Plant Extracts/pharmacology , Plant Leaves/chemistry , RadiometryABSTRACT
The modulation in biochemical status of skin and hepatic tissue at the time point of commencement of promotion stage of skin carcinogenesis in mice and its intervention with aqueous Azadirachta indica leaf extract (AAILE) were investigated. 7,12-Dimethylbenz(a)anthracene (DMBA, 500 nmol/100 ul of acetone) was applied topically for 2 weeks (twice weekly), followed by phorbol-12-myristate-13-acetate (TPA, 1.7 nmol/100 ul) twice weekly for 6 weeks on the depilated skin of mice and AAILE was administered orally at a dose level of 300 mg/kg body wt thrice a week for 10 weeks. DMBA/TPA treatment upregulated the phase I enzymes in skin and hepatic tissue, as revealed by the increased cytochrome P450 (CYP) and cytochrome b5 (cyt b5) levels and aryl hydrocarbon hydroxylase (AHH) activity when compared to the control group and differentially modulated the activities of phase II enzymes like glutathione-s-transferase (GST), DT-diaphorase (DTD) and uridine diphosphate glucuronosyltransferase (UDP-GT). AAILE treatment decreased the DMBA/TPA-induced increase in cutaneous CYP level and enhanced the DTD and UDP-GT activities when compared with DMBA/TPA group. In the hepatic tissue of AAILE + DMBA/TPA group, an increase in UDP-GT activity was observed when compared to DMBA/TPA group. DMBA/TPA treatment did not alter the skin lipid peroxidation (LPO) level when compared to control group, however, in the animals that received AAILE treatment along with DMBA/TPA, a significant increase in LPO was observed when compared to control group. This was associated with a decrease in cutaneous reduced glutathione (GSH) level of AAILE + DMBA/TPA group. Enhanced LPO level was observed in the hepatic tissue of DMBA/TPA and AAILE + DMBA/TPA groups when compared to control group. However, no alteration was observed in their hepatic GSH levels. The micronuclei score in hepatic tissue did not exhibit significant inter-group differences. The results of the present study suggest that apart from skin, liver may be affected during DMBA/TPA-induced skin tumorigenesis. AAILE treatment has the ability to modulate these changes potentially influencing the process of tumor formation. These findings seem to be important to carcinogenesis and its intervention with anti-cancer agents.
Subject(s)
9,10-Dimethyl-1,2-benzanthracene/pharmacology , Animals , Antineoplastic Agents/pharmacology , Antioxidants/metabolism , Azadirachta/chemistry , Cell Transformation, Neoplastic , Cytochrome P-450 Enzyme System/metabolism , Cytochromes b5/metabolism , Gene Expression Regulation, Neoplastic , Glutathione Transferase/metabolism , Lipid Peroxidation , Liver/drug effects , Liver/metabolism , Male , Mice , Micronucleus Tests , Neoplasms, Experimental/chemically induced , Phytotherapy/methods , Plant Extracts/pharmacology , Plant Leaves , Skin/drug effects , Skin/metabolism , Skin Neoplasms/chemically induced , Skin Neoplasms/drug therapy , Tetradecanoylphorbol Acetate/pharmacology , Xenobiotics/chemistryABSTRACT
The present study investigated the chemopreventive potential of geraniol, an acyclic monoterpene alcohol, by monitoring the tumor incidence and analyzing the status of phase II detoxification agents, lipid peroxidation by products and antioxidants in 7,12-dimethylbenz(a)anthracene (DMBA) induced mouse skin carcinogenesis. Skin tumor was developed by painting DMBA (25 μg in 0.1 ml acetone mouse-1) in the shaved back of the mice, twice weekly for 8 weeks. We noticed 100% skin tumor formation in mice treated with DMBA alone. The status of phase II detoxification agents and antioxidants were decreased where as lipid peroxidation by products were increased in tumor bearing mice. Oral administration of geraniol at a dose of 250 mg kg-1 body weight significantly prevented the tumor formation as well as brought back the status of phase II detoxification agents, lipid peroxidation by products and antioxidants to near normal range in DMBA treated mice. Present results suggest that geraniol might have inhibited abnormal cell proliferation occurring in skin carcinogenesis by modulating the activities of phase II detoxification agents and through its free radical scavenging potential.
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It is reported that a fermented soybean food, Doenjang, has strong antimutagenic and cytotoxic effect on cancer cells. This study investigated the effect of Chungkookjang, another traditional popular Korean soybean fermented food, on growth of cancer cells: HL-60, SNU-638 and MCF-7, and also its in vivo antitumorigenic effect in DMBA-induced mammary tumor rat model. For the in vitro study, Chungkookjang and steamed soybeans were extracted with ethanol and sequentially fractioned with 5 kinds of solvents differing in grades of polarity such as hexane, dichloromethane, ethylacetate, butanol and water. Almost all Chungkookjang extracts significantly inhibited the growth of HL-60 (human leukemic cancer cell), SNU-638 (human gastric cancer cell) and MCF-7 (human breast cancer cell) when compared to steamed soybean extracts. Butanol fraction of Chungkookjang extract especially showed a remarkable inhibitory effect in all the three kinds of cancer cells. To induce a mammary gland tumor, DMBA (50 mg/BW) was administered to 50 day-old female rats and followed by Chungkookjang or steamed soybean supplemented diets. Freezedried Chungkookjang powder (20% of diet in wet weight) was added to AIN-93G based diet for the Chungkookjang group of rats. Likewise, steamed soybean powder containing equal protein content to that of Chungkookjang powder was supplemented to soybean group of rats. At 13 weeks later, the mammary tumor incidence, average tumor number and tumor weight a rat were lower in Chungkookjang group compared to the control or soybean group. In conclusion, Chungkookjang showed a strong inhibitory effect on cancer cell growth in vitro, as well as a more preventive effect against chemically induced mammary tumorigenesis in vivo, while steamed soybeans did not. Therefore, these results suggest that Chungkookjang acquire its anticancer activity through the fermentation process.
Subject(s)
Animals , Female , Humans , Rats , 9,10-Dimethyl-1,2-benzanthracene , Breast Neoplasms , Carcinogenesis , Diet , Ethanol , Fermentation , Incidence , Mammary Glands, Human , Methylene Chloride , Models, Animal , Solvents , Glycine max , Steam , Stomach Neoplasms , Tumor Burden , WaterABSTRACT
PURPOSE: The incidence of salivary gland tumor is approximately 2% among all head and neck tumors, of which malignant cases account for only about 5%. Much research has been performed in order to clarify the mechanism of oncogene activation, however salivary gland tumors remain understudied. We performed this study in order to characterize the ras gene in these tumors. MATERIALS AND METHODS: We treated white rats with 7, 12-dimethylbenz[a]anthracene (DMBA) and confirmed the occurrence of salivary gland tumors after ten to thirty weeks. Isolated genomic DNAs from tumor tissues were added to NIH 3T3 cells. In order to detect Ha-ras mutations, we performed a two-step PCR-RFLP and 7analyzed the mutated sequences. RESULTS: We induced salivary gland tumors by DMBA treatment in white rats. Isolated DNAs from the tumor tissues transformed the NIH 3T3 cells. Point mutations were observed in codons 12 and 61 of the Ha-ras oncogene. The total frequency of point mutations was 13.9% in DMBA-induced salivary gland tumors in rats. CONCLUSION: Our results demonstrate that a variety of cancers ras oncogene mutations were also found in salivary gland tumors. We confirmed that a point mutation of the Ha-ras oncogene in a DMBA-induced salivary gland tumor occurs at a frequency of 13.9%.
Subject(s)
Animals , Rats , 9,10-Dimethyl-1,2-benzanthracene , Codon , DNA , Genes, ras , Head , Incidence , Neck , NIH 3T3 Cells , Oncogenes , Point Mutation , Salivary GlandsABSTRACT
The incidence of tumor and the time of expression, cellular localization and the molecular weight of tumor associated proteins of rat skin tumor induced by 7,12-dimethylbenz[a]anthracene (DMBA) with or without 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were studied. The time of the development of skin tumors in 0.1% DMBA-TPA treated rats was significantly shorter than that in rats which were treated with DMBA alone. In the complete carcinogenesis case, papillomas developed more slowly and were less common and also squamous cell carcinomas appeared much later. From the analysis of the proteins of each experimental group by SDS-PAGE and two dimensional gel electrophoresis, at least three tumor associated proteins were identified (54kd, pl = 5.66; 27kd, pl = 5.85; 11kd, pl = 4.90). Also these proteins were found in rat dorsal skin from 14 days gestation to 21 days postpartum, and disappeared after 28 days. In conclusions, two stage skin carcinogenesis could be successfully demonstrated in Sprague-Dawley rats and abnormal proteins were produced in DMBA or DMBA-TPA induced skin tumor. The tumor associated proteins of skin tumor induced by DMBA or DMBA-TPA were appeared at the late initiation stage or early promotion stage, and they were localized in plasma membrane and were glycoproteins that are thought to be related to the epidermal differentiation process.
Subject(s)
Rats , 9,10-Dimethyl-1,2-benzanthracene , Animals , Antigens, Surface/analysis , Carcinoma, Squamous Cell/analysis , Cell Membrane/metabolism , Comparative Study , Glycoproteins/analysis , Membrane Proteins/analysis , Papilloma/analysis , Rats, Inbred Strains , Skin Neoplasms/analysis , Tetradecanoylphorbol AcetateABSTRACT
The incidence of tumor and the time of expression, cellular localization and the molecular weight of tumor associated proteins of rat skin tumor induced by 7,12-dimethylbenz[a]anthracene (DMBA) with or without 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were studied. The time of the development of skin tumors in 0.1% DMBA-TPA treated rats was significantly shorter than that in rats which were treated with DMBA alone. In the complete carcinogenesis case, papillomas developed more slowly and were less common and also squamous cell carcinomas appeared much later. From the analysis of the proteins of each experimental group by SDS-PAGE and two dimensional gel electrophoresis, at least three tumor associated proteins were identified (54kd, pl = 5.66; 27kd, pl = 5.85; 11kd, pl = 4.90). Also these proteins were found in rat dorsal skin from 14 days gestation to 21 days postpartum, and disappeared after 28 days. In conclusions, two stage skin carcinogenesis could be successfully demonstrated in Sprague-Dawley rats and abnormal proteins were produced in DMBA or DMBA-TPA induced skin tumor. The tumor associated proteins of skin tumor induced by DMBA or DMBA-TPA were appeared at the late initiation stage or early promotion stage, and they were localized in plasma membrane and were glycoproteins that are thought to be related to the epidermal differentiation process.
Subject(s)
Rats , 9,10-Dimethyl-1,2-benzanthracene , Animals , Antigens, Surface/analysis , Carcinoma, Squamous Cell/analysis , Cell Membrane/metabolism , Comparative Study , Glycoproteins/analysis , Membrane Proteins/analysis , Papilloma/analysis , Rats, Inbred Strains , Skin Neoplasms/analysis , Tetradecanoylphorbol AcetateABSTRACT
The effect of a single subcutaneous administration of 7,12-dimethylbenz( a)anthracene, the powerful complete carcinogen, under the skin was studied in the rabbit. The study reports an ordered sequential biochemical and cytophotometric changes induced by the carcinogen. While the biochemical studies comprised of sequential quantitative estimations of DNA, RNA and protein per mg of skin, the cytophotometric studies consisted of the estimation of the level of macromolecules in a cell/nucleus, in different skin constituents viz. epidermis, hair follicle shaft region and hair follicle bulb region. Biochemical results indicate an initial rise in the level of DNA and RNA and reduction in protein upto 20 days. From 40 to 60 days treatment duration there was a ‘steady-state’ showing a constant level of all the parameters while the highest peak was observed on the 80th day. The site of these biochemical changes among different skin constituents was determined with the help of cytophotometer which indicates the highest level of nucleic acids in epidermis region right from the initial stage (i.e. 10th day) to the 90th day of treatment in comparison to two other regions hair follicle shaft and hair follicle bulb regions. Histological studies, on the other hand, reveal a greatly, though gradual, increased nuclear area and the highest rate of proliferation only in hair follicle bulb region, thus suggesting a definite role of this region of the skin in the carcinogenesis. All these results suggest that the important event in the initiation phase of 7,12-dimethylbenz( a)anthracene mediated skin carcinogenesis in rabbit might be associated with epidermal region but the role of hair follicle bulb region should also be considered as of an equal significance during the process. A conspicuous difference in the behaviour of rabbit skin constituents has been noted when the results of the study are compared with the earlier reports on mice.
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Objective: To investigate the anticancer action of taurine and its potential mechanisms. Methods: 101 weanling female SD rats were randomly divided into four groups. They were:(1)control group (CL):fed a basic diet;(2)high fat group(HF):fed a high fat diet (10% lard);(3)taurine group (Tau):fed a taurine diet (5% taurine);(4)taurine and high fat group(TH):fed a mixed diet (5%taurine and 10% lard). 10mg DMBA were given to each rat by gavage at age of 6 weeks. Then the rats were fed assigned diet for 26 weeks. By 5 weeks after DMBA administration the rats were palpated once weekly and the time, size, location of each tumor were recorded. The examinations made at the end of experiment were listed below: CI, LTT, serum antibody, SOD, MDA, GSH Px, TC, TG, LDL C. Results: The tumor incidence in group HF rats was higher than that in group CL, Tau and TH rats (P