芥菜籽调节机体免疫系统预防实验性大鼠大肠癌的机制

目的 研究芥菜籽（mustard seed,MS）对淋巴细胞的过继免疫,验证其免疫调节作用,并初步探讨免疫预防机制。方法 48只5周龄的雄性Wistar大鼠,随机分为4组,每组12只。用l,2-二甲基肼(DMH)腹腔注射诱导大鼠大肠癌模型,分离大鼠脾脏淋巴细胞过继免疫对大鼠进行回输,32周实验结束时,观察记录各组大鼠有无肿瘤发生及发生数目和肿瘤大小,计算肿瘤发生率,肿瘤胸腺指数和脾指数,并观察脾细胞的CD4+T细胞和CD8+T细胞的表达情况。结果 DMH成功诱导大鼠大肠癌模型,正常对照组未见肿瘤发生,二甲基肼(DMH)组,肿瘤发生率为91.7%。淋巴细胞回输组和7.5%MS组肿瘤发生率比DMH组分别降低了40%、50%, MS干预组及淋巴细胞回输组胸腺指数和脾指数均明显大于DMH组（P<0.05）,并且CD4+T细胞与CD8+T细胞比值降低（P<0.05）。结论 芥菜籽可以调节机体免疫系统,通过增强机体免疫力预防DMH诱导大肠癌的发生。     

Effects of specific active immunization on tumor recurrence following primary tumor resection in WF rats with 1,2-dimethylhydrazine-induced bowel cancer

Primary gastrointestinal tumors were induced in male WF rats by 16 weekly sc injections of 1,2-dimethylhydrazine [(DMH) CAS: 540-73-8; 20 mg/kg/wk]. Twenty-four to 28 weeks after the start of DMH injections, all rats were surgically explored and gastrointestinal tumors were resected. Rats with no remaining microscopic disease after operation were immunized with one of four tumor isografts. The first isograft, DMH-W163, is a poorly differentiated mucinous adenocarcinoma explanted from a colon cancer in a DMH-treated animal. It has been shown to possess antigens that cross-react with other DMH-induced bowel adenocarcinoma isografts. The second isograft, DMH-W49, is a carcinosarcoma explanted from a DMH-treated primary colon cancer. It has intermediate antigenic cross-reactivity with other colon adenocarcinoma isografts in the WF model. The third isograft, DMH-W15, is a sarcoma explanted from a DMH-induced colon cancer that does not possess antigens cross-reactive with other DMH-induced colon adenocarcinomas. The fourth isograft, SPK, is a spontaneous (non-DMH-induced) renal cell carcinoma that is immunogenic but should not contain tissue-type-specific antigens cross-reacting with the bowel cancers. Immunized rats received three sc weekly injections of 1 X 10(3) irradiated cells. Concomitant control rats received no immunization after resection of the primary tumor. Within 24 weeks of primary tumor resection, 12 of 16 (75%) rats not immunized had tumor recurrence. Only 8 of 24 (34%) rats immunized with DMH-W163 had tumor recurrence (P less than .025 compared to controls). Fifty percent of animals (10/20) immunized with the carcinosarcoma DMH-W49 had a recurrence. Animals immunized with the non-cross-reacting DMH-W15 sarcoma isograft had a recurrence rate similar to that of controls (16/20, 75%). The rats immunized with SPK were not protected from recurrence. Twelve of 19 (63%) had a recurrence at or near the suture line within 24 weeks following primary tumor resection. These results confirm that adjuvant immunotherapy can decrease the rate of recurrence following primary tumor resection in this model. In addition, immunogens that possessed tissue-type-specific antigens were more effective in preventing tumor recurrence than those that did not.     

芥菜籽通过抗氧化和免疫偏移预防大肠肿瘤的实验研究

背景与目的：近年来有关十字花科植物预防肿瘤的研究,主要探讨其抗氧化、抗突变作用、调节免疫功能及诱导细胞凋亡等。芥菜籽(mustard seeds,MS)是十字花科植物的种子。本研究旨在探讨MS对1,2-二甲基肼(1,2-dimethylhydrazine,DMH)诱导的大鼠大肠肿瘤的抗氧化和免疫偏移作用机制。方法：将48只Wistar雄性大鼠随机均分为4组：DMH模型组(模型组)、DMH+5%MS干预组(5%MS干预组)、DMH+7.5%MS干预组(7.5%MS干预组)和正常对照组。模型组和MS干预组每周按30 mg/kg剂量给予DMH腹腔注射1次,连续20周,均于32周时处死大鼠观察大肠肿瘤发生率并HE染色确定肿瘤的组织分型,检测血清脂质过氧化产物丙二醛(malondialdehyde,MDA)水平、抗氧化酶活力、Th1和Th2亚群细胞因子含量。结果：正常对照组大鼠无肿瘤发生。模型组总成瘤率为100%,5%MS干预组和7.5%MS干预组总成瘤率分别降低33.3%和58.3%(P<0.05)。DMH诱导大鼠形成肿瘤的过程中,模型组MDA水平和Th2亚群细胞因子含量均显著高于正常对照组(P<0.05);而抗氧化酶活力明显低于正常对照组(P<0.05)。经MS干预后MDA呈显著下降趋势(P<0.05),而抗氧化酶活力和Th1亚群细胞因子含量均呈显著升高趋势(P<0.05)。结论：芥菜籽显著降低DMH化学诱导的大鼠大肠肿瘤的发生,作用机制可能与其抗氧化作用和免疫平衡偏移有关。     

芥菜子对DMH诱导大鼠大肠癌预防作用的体内研究

目的:探讨芥菜籽(MS)对1,2-二甲基肼(DMH)诱导的大鼠大肠癌的预防作用.方法:用DMH腹腔注射诱导大鼠发生大肠癌,观察MS对诱癌率及胸腺指数和脾指数等的影响.结果:用DMH成功诱导大鼠大肠癌模型,正常对照组未见肿瘤发生,DMH组腺癌发生率为83.33％ (10/12),腺瘤发生率为16.67％(2/12),总肿瘤发生率为100％(12/12),肝及淋巴结转移率为58.33％(7/12).5％MS和7.5％MS组腺癌发生率比DMH组分别降低了58.33％和75.00％(X2=15.662,P=0.000),肝及淋巴结转移率分别降低了41.66％和50.00％(x2 =8.585,P=0.014),总肿瘤发生率[66.67％(8/12),41.70％(5/12)]亦显著低于DMH组(x2=9.687,P=0.008),而腺瘤发生率[41.67％(5/12),33.33％(4/12)]则高于DMH组.7.5％MS组大鼠胸腺指数和睥指数均明显大于DMH组,P值分别为0.013和0.037;同时5％MS组胸腺指数也显著大于DMH组,P=0.039.结论:MS对DMH诱导的大肠癌有预防发生及减少转移的作用,并能改善机体免疫功能.     

Effect of DL-buthionine-S,R-sulfoximine on 1,2-dimethyl-hydrazine-induced colonic tumors in rats

The effect of DL-buthionine-S,R-sulfoximine (BSO), a specific inhibitor of glutathione biosynthesis, on colon tumor development was studied in rats. Weanling male Sprague-Dawley rats were randomly assigned to one of three groups following a week of adaptation. Group 1 rats received BSO (4.5 mM) daily in the drinking water one week before 1,2-dimethylhydrazine (DMH) injections and continued to receive BSO daily until sacrificed; group 2 rats received BSO (4.5 mM) after the last DMH injection, and continued to receive BSO daily until sacrificed; group 3 rats did not receive BSO. All experimental rats received 20 weekly subcutaneous injections of DMH (20 mg/kg body wt.) for colon tumor induction. The tumor incidence was lower in group 1 (54%) than in group 2 (97%) or group 3 (96%). The median tumor size is significantly smaller in group 1 (11 mm2) than group 3 (46 mm2). The group 2 had the largest median tumor size (65 mm2).     

Chronic Trypanosoma cruzi infection associated with low incidence of 1,2-dimethylhydrazine-induced colon cancer in rats

Experimental data have demonstrated that chronic infection with intracellular parasites may enhance resistance against some types of tumour. This phenomenon has not yet been demonstrated for experimental Trypanosoma cruzi chronic infection. This study investigated the effect of a specific colon cancer inducing drug, 1,2-dimethylhydrazine (DMH), on chronically T.cruzi infected Wistar rats. Infection was obtained by inoculation of 10(5) tripomastigote forms by subcutaneous (s.c.) route. Acute phase of the infection was monitored every other day by examination of a blood smear from each animal until negativation. In the early chronic phase of the infection, colon adenocarcinoma was induced by weekly s.c. injections of DMH at a dose of 20 mg/kg body weight for 12 weeks. 102 animals were divided in four test groups: 39 infected rats received DMH (group 1); 32 non-infected rats received DMH (group 2); 16 infected rats and 15 non-infected animals were used as control groups. Animals were killed 6 months after the first dose of DMH. The whole colon was removed and prepared for light microscopic examination. Twelve animals from group 1 and 22 from group 2 had colon adenocarcinomas, the proportion of cancer being 30.7 and 68.7%, respectively (chi(2) = 10.16; P < 0.05). The relative risk of having a colon tumor in infected animals (group 1) was 0.45 (IC 95% 0.26-0.76), which is a protective risk compared with non-infected animals. These findings show that chronic infection with T.cruzi is associated with a lower incidence of DMH-induced colon cancer in rats.     

Surgical prophylaxis against large bowel tumors in an animal model

Subtotal removal of high-risk organs is of uncertain value as cancer prophylaxis. This study examined to what extent partial colectomy prevented carcinogen-induced large bowel tumors. Male Fischer 344 rats (N = 98) were given five weekly subcutaneous injections of azoxymethane 7 mg/kg, then treated as follows: group I (controls), the ileocecal junction was divided and reanastomosed without resection; group II, a proximal 1/3 colon resection was performed; and group III, a proximal 2/3 colon resection was performed. After 7 months the rats were sacrificed and colorectal tumors confirmed histologically. Sixty-nine animals survived for analysis. Tumor incidence and average number of tumors per rat were not significantly changed by resection. Surgical prophylaxis was compromised by a high frequency of multiple tumors and by a higher than expected frequency of tumors in the remaining bowel.     

The effect of alloimmunization on recurrence in an experimental colon cancer model

Primary bowel tumors were induced in Wistar/Furth (W/Fu) rats by 16 weekly injections of 1,2-dimethylhydrazine (DMH). After curative resection, 70% to 75% of control rats who receive no further treatment developed local or regional recurrence within 22 weeks. Rats immunized with three weekly subcutaneous inoculations of 1 X 10(6) irradiated (10,000 rad) Brown Norwegian (BN) X W/Fu F1 or Buffalo (Bu) tumor cells (both containing colon cancer tissue-type specific antigens [TSA] but differing from the W/Fu at Ag-B [histocompatibility] loci) developed recurrent tumor at a rate not significantly different from untreated or concurrent Ag-B antigen matched non-TSA treated controls. By 22 weeks after tumor resection, 63% of rats immunized with BN X W/Fu F1 colon adenocarcinoma and 52% of those immunized with Bu adenocarcinoma had recurred. Sixty-one percent and 44% were the respective recurrence rates for rats immunized with strain matched renal cell tissue. These data show nonspecific protection against tumor recurrence because of alloimmunization but clearly demonstrate the subordination of any beneficial colon cancer TSA immunotherapeutic effect by contained histocompatibility antigens. The problem of such nonspecific immune stimulation by alloantigen overriding an expected specific effect by TSA and possible alternative methods of immunization to prevent this phenomenon are discussed.     

结肠、直肠手术在肿瘤细胞减灭术中的作用

目的　探讨结肠、直肠手术在治疗卵巢上皮性癌和原发腹膜癌患者的手术指征和治疗效果。方法　对 1988年 6月～2 0 0 1年 5月在我院妇科接受开腹手术同时行结肠、直肠手术的 18例妇科恶性肿瘤进行回顾性分析 ,其中卵巢上皮性癌 16例和原发腹膜癌 2例。结果　有 8例在初次手术中完成结肠、直肠手术 ,10例在处理复发性癌或者姑息性手术中进行。 18例中接受结肠切除或者部分乙状结肠直肠手术 ,肠吻合术 14例 ,接受结肠造瘘术 4例 ,其中 1例于结肠造瘘术后 14个月行结肠造瘘还纳术。 18例中有 17例切除肠管 ,术后病理显示肿瘤侵犯至肠浆膜层 7例 ,至浆肌层 5例 ,至粘膜下层 3例 ,至粘膜层 2例。有 7例术后残留癌 <2cm ,10例 >2cm ,1例行姑息性手术未切除肠管。术后 1年生存率为 76 % ,2年为 2 9% ,3年为 19%。有 2例术后存活已超过 5年。结论　对卵巢上皮性癌或者原发性腹膜癌患者实施结肠、直肠手术的主要目的是为达到肿瘤细胞减灭或者为缓解肠梗阻症状。选择一组合适的妇科恶性肿瘤病人术前最好肠道准备 ,术中尽量采用肠切除肠吻合术 ,减少结肠造瘘术 ,对提高治疗效果 ,延长病人寿命是有益的。     

Long term administration of granulocyte-macrophage colony stimulating factor decreases development of 1-2 dimethylhydrazine-induced colon cancer in rats

BACKGROUND AND OBJECTIVES: The antitumoral activities of granulocyte-macrophage colony stimulating factor (GM-CSF) were shown earlier. In this study, the effects of GM-CSF were investigated on colon cancer induced by 18 weeks of 1-2 dimethylhydrazine (DMH) administration in rats. METHODS: Four groups received subcutaneous saline (n = 20), 15 mg/kg DMH (n = 30), DMH +6 microg/kg GM-CSF (n = 30), and DMH +12 microg/kg (n = 30) GM-CSF. RESULTS: The average number of tumors (2.8 vs. 1.5) and mean tumor volume (179 +/- 36 vs. 27 +/- 9 mm(3); means +/- SEM) were reduced in DMH + GM-CSF groups as compared to the DMH group (n = 30, P < 0.01). DMH-induced enhancement of free radicals and lipid peroxidation were decreased in DMH + GM-CSF group (n = 8-12, P < 0.05). The magnitude of DMH-induced alterations in superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities was lowered in the DMH + GM-CSF group (n = 12-16, P < 0.05). DMH-induced increases in the total nitrite/nitrate levels and the nitric oxide synthase (NOS) activity (n = 10-12, P < 0.05) were also reduced in the DMH + GM-CSF group (n = 8-9, P < 0.05). CONCLUSIONS: The results indicate that GM-CSF inhibits the development of DMH-induced colon cancer in rats and suggest that inhibition of oxidative stress and NO pathway are involved in the observed antitumoral effects.     

Dietary calcium and vitamin D modulate 1,2-dimethylhydrazine-induced colonic carcinogenesis in the rat

To determine whether supplemental dietary calcium and/or vitamin D deficiency are involved in modulating colon cancer induced by 1,2-dimethylhydrazine (DMH), Sprague-Dawley rats were fed diets containing either: (a) a normal content of calcium (0.87%) and phosphorus (0.60%) with 2.2 IU of vitamin D3 per g of feed (group A); (b) the same diet as group A, but with calcium and phosphorus increased to 1.80 and 0.80%, respectively (group B); or (c) a vitamin D-deficient diet with supplemental calcium (1.80%) and phosphorus (0.80%) (group C). After 6 weeks on their respective diets, one-half the animals in each group were given s.c. injections of either vehicle or DMH (20 mg/kg body weight/week) for 26 weeks. Animals were then sacrificed and the incidence of tumors as well as the number of tumors per tumor-bearing rat were determined. Colonic mucosal polyamine levels were measured after 15 weeks of exposure to vehicle or DMH, before development of histologically recognizable neoplasms. The results of these experiments demonstrated that neither calcium supplementation alone nor supplemental calcium in conjunction with vitamin D deficiency altered the incidence of colonic cancer induced by this carcinogen. Supplemental calcium, however, significantly decreased the number of rats with multiple tumors and reduced tumor size. Moreover, vitamin D deficiency abolished these protective effects of calcium on colon cancer in this experimental model. DMH treatment increased polyamine levels in the premalignant colonic mucosa in group A rats. This carcinogen-induced effect was blunted by high dietary calcium. Vitamin D-deficient, calcium-supplemented rats (group C) showed an increase in N1-acetylspermidine, but not the other polyamines, with DMH treatment.     

Kinetics of the non-neoplastic mucosa of the large bowel of dimethylhydrazine-treated rats.

Administration of 1,2 dimethylhydrazine (DMH) to rats by weekly s.c. injections causes the development of multiple epithelial tumours of the large bowel. These appear to arise as localized dysplastic abnormalities in hitherto apparently morphologically normal crypts. This study was undertaken in order to examine cell proliferation in such apparently normal crypts of DMH-treated animals. A number of proliferative abnormalities are evident, including changes in the size of the crypts, changes in the disposition of proliferating cells within them and reduced cell-cycle times. The nature and the extent of the abnormalities vary from site to site along the length of the bowel, and reflect the vulnerability of the different segments of the bowel, not only to the carcinogenic effects of DMH, but also to short-term toxicity.     

Inhibitory Effects of Crude α-Mangostin,a Xanthone Derivative,on Two Different Categories of Colon Preneoplastic Lesions Induced by 1, 2-dimethylhydrazine in the Rat

The purpose of this study was to examine whether crude á-mangostin (a major xanthone derivative in mangosteen ‍pericarp (Garcinia mangostana)) has short-term chemopreventive effects on putative preneoplastic lesions involved ‍in rat colon carcinogenesis. The crude preparation was obtained by simple recrystallization of an ethylacetate ‍extract of mangosteen pericarps. A total of 33 five-week-old male F344 rats were randomly divided into 5 experimental ‍groups. Rats in groups 1-3 were given a subcutaneous injection of 1,2-dimethylhydrazine (DMH)(40 mg/kg body ‍weight) once a week for 2 weeks. Starting one week before the first injection of DMH, rats in groups 2 and 3 were fed ‍a diet containing 0.02% and 0.05% crude á-mangostin, respectively, for 5 weeks. Rats in group 4 also received the ‍diet containing 0.05% crude á-mangostin, while rats in group 5 served as untreated controls. The experiment was ‍terminated 5 weeks after the start. Dietary administration of crude á-mangostin at both doses significantly inhibited ‍the induction and/or development of aberrant crypt foci (ACF) (P<0.05 for 0.02% crude á-mangostin, P<0.01 for ‍0.05% crude á-mangostin), when compared to the DMH-treated group (group 1). Moreover, treatment of rats with ‍0.05% crude á-mangostin significantly decreased dysplastic foci (DF) (P<0.05) and â-catenin accumulated crypts ‍(BCAC) (P<0.05), to below the group 1 values. The proliferating cell nuclear antigen (PCNA) labeling indices of ‍colon epithelium and focal lesions in groups 2 and 3 were also significantly lower than in group 1 and this effect ‍occurred in a dose dependent manner of the crude á-mangostin. This finding that crude á-mangostin has potent ‍chemopreventive effects in our short-term colon carcinogenesis bioassay system suggests that longer exposure might ‍result in suppression of tumor development. ‍     

Inhibitory effect of peptide Epitalon on colon carcinogenesis induced by 1,2-dimethylhydrazine in rats

The effect of synthetic pineal peptide Epitalon (Ala-Glu-Asp-Gly) on colon carcinogenesis was firstly studied in rats. Eighty 2-month-old outbred male LIO rats were subdivided into four groups and were weekly exposed to five subcutaneous injections of 1,2-dimethylhydrazine (DMH) at a single dose of 21 mg/kg body weight. Additionally, 5 days a week, some of the rats were given subcutaneous injections of saline at a dose of 0.1 ml during the whole experiment (group 1, control) or Epitalon at a single dose of 1 microg during the whole experiment (group 2), Epitalon after termination of carcinogen injections (group 3) or during the period of DMH exposure (group 4). Colon carcinomas developed in 90-100% of DMH-treated rats. The number of total colon tumors per rat was 4.1; 2.7; 3.7; 2.9 in groups 1, 2, 3, 4, respectively (the difference in groups 2 and 4 compared with group 1 is significant). In rats from group 2, colon tumors were smaller than in control animals. In group 2, the incidence, as well the multiplicity of tumors in ascending and descending colon, were significantly decreased in comparison with group 1. In group 4, the mean number of tumors per rat was significantly decreased, too. A trend to decrease the number of tumors in the rectum in rats from groups 2, 3 and 4, treated with Epitalon was found. Epitalon inhibited also the development of tumors in jejunum and ileum. Thus, our results demonstrated an inhibitory effect of Epitalon on chemically induced bowel carcinogenesis in rats.     

Melatonin and colon carcinogenesis: I. Inhibitory effect of melatonin on development of intestinal tumors induced by 1,2-dimethylhydrazine in rats

The effect of pineal indole hormone melatonin on colon carcinogenesis was firstly studied in rats. Two-month-old outbred female LIO rats were weekly exposed to 15 (experiment 1, groups 1 and 2) or to five (experiment 2, groups 1 and 2) s.c. injections of 1,2-dimethylhydrazine (DMH) at a single dose of 21 mg/kg of body weight. From the day of the first injection of the carcinogen DMH, the rats from groups 2 (experiments 1 and 2) were given melatonin five days a week during the night-time (from 18:00 h to 8:00 h), dissolved in tap water at 20 mg/l. The experiment was finalized in 6 months after the first injection of DMH. In both experiments the majority of tumors were localized in the descending colon. Tumors of the small intestines developed only in rats from experiment 1. Total incidence of colon tumors as well as tumors in different parts of the colon and the mean number of tumors per rat were much higher in rats from both groups in experiment 1 than that in rats from experiment 2. In experiment 1 melatonin failed to influence the total incidence of colon tumors. However, incidence of carcinomas in the ascending colon was significantly reduced (P < 0.01). The multiplicity of total colon tumors per rat, as well as the mean number of tumors, ascending and descending colon per rat, was also decreased under the influence of melatonin (group 2 vs group 1, P < 0.01). In the same experiment, melatonin slightly decreased the depth of tumor invasion and increased number of highly differentiated colon carcinomas induced by DMH. The percentage of small tumours in the descending colon among rats from group 2 was higher than that of group 1. Treatment with melatonin was also followed by a decrease in the multiplicity of DMH- induced tumors of the duodenum (group 2 vs group 1, P < 0.05) and by a decrease in the incidence of jejunum and ileum tumors (group 2 vs group 1, P < 0.05). In experiment 2, the inhibitory effect of melatonin on DMH-induced colon carcinogenesis was much more expressed than that in experiment 1. Thus, in group 1 the incidence of total colon tumors, ascending and descending colon tumors, was significantly decreased in comparison with group 2; also melatonin reduced the number of tumors per rat in the ascending and descending colon. The number of colon tumors that invaded only mucosa was significantly higher in group 2 than in group 1, P < 0.05. The ratio of highly differentiated tumors was increased (P < 0.05) and the ratio of low-differentiated tumors was decreased (P < 0.05) in rats exposed to melatonin (group 4) as compared with group 3. The number of large size tumors in the ascending and descending colon was decreased whereas the number of small size tumors (<10 mm2) was increased in those parts of the colon that were under the influence of melatonin in experiment 2. Thus, our results demonstrate the inhibitory effect of melatonin on intestinal carcinogenesis induced by DMH in rats.      

Selenium as a chemopreventive agent in experimentally induced colon carcinogenesis

AIM: To elucidate the chemopreventive efficacy of selenium during experimentally induced colon carcinogenesis.METHODS: Thirty-two male wistar rats were divided into four groups: group I (normal control); group II [1,2-dimethylhydrazine (DMH) treated]; group III (selenium treated); and group IV (DMH + selenium treated). Groups II and IV were given subcutaneous injections of DMH (30 mg/kg body weight) every week for 20 wk. Selenium, in the form of sodium selenite, was given to groups III and IV at 1 ppm in drinking water ad libitum for 20 wk. At the end of the study, rats were sacrificed and their colons were analyzed for the development of tumors, antioxidant enzyme levels and histological changes.RESULTS: 100% of the DMH treated rats developed tumors, which was reduced to 60% upon simultaneous selenium supplementation. Similarly, tumor multiplicity decreased to 1.1 following selenium supplementation to DMH treated rats. Levels of lipid peroxidation, glutathione-S-transferase, superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) decreased following DMH treatment, whereas levels of glutathione (GSH) and glutathione reductase (GR) significantly increased in DMH treated rats. Selenium administration to DMH treated rats led to an increase in the levels of lipid peroxidation, SOD, catalase, glutathione-S-transferase and GPx, but decreased the levels of GSH and GR. Histopathological studies on DMH treated rats revealed dysplasia of the colonic histoarchitecture, which showed signs of improvement following selenium treatment.CONCLUSION: The study suggests the antioxidative potential of selenium is a major factor in providing protection from development of experimentally induced colon carcinogenesis.     

Protective Role of Aspirin,Vitamin C,and Zinc and their Effects on Zinc Status in the DMH-Induced Colon Carcinoma Model

Chemoprotection refers to the use of specific natural or synthetic chemical agents to suppress or prevent theprogression to cancer. The purpose of this study is to assess the protective effect of aspirin, vitamin C or zinc ina dimethyl hydrazine (DMH) colon carcinoma model in rats and to investigate the effect of these supplementson changes associated with colonic zinc status. Rats were randomly divided into three groups, group 1 (aspirin),group 2 (vitamin C) and group 3 (zinc), each being subdivided into two groups and given subcutaneous injectionof DMH (30 mg/kg body wt) twice a week for 3 months and sacrificed at 4 months (A-precancer model) and6 months (B-cancer model). Groups 1, 2, 3 were simultaneously given aspirin, vitamin C, or zinc supplementrespectively from the beginning till the end of the study. It was observed that 87.5% of rats co-treated with aspirinor vitamin C showed normal colonic histology, along with a significant decrease in colonic tissue zinc at bothtime points. Rats co-treated with zinc showed 100% reduction in tumor incidence with no significant change incolonic tissue zinc. Plasma zinc, colonic CuZnSOD (copper-zinc superoxide dismutase) and alkaline phosphataseactivity showed no significant changes in all 3 cotreated groups. These results suggest that aspirin, vitamin Cor zinc given separately, exert a chemoprotective effect against chemically induced DMH colonic preneoplasticprogression and colonic carcinogenesis in rats. The inhibitory effects are associated with maintaining the colonictissue zinc levels and zinc enzymes at near normal without significant changes.     

The Effects of Phyllanthus niruri Linn on Infiltrating Dendritic Cell and Ratio of Neutrophile/Lymphocytes in Chemotherapy of Sprague-Dawley Rats with Colorectal Cancer

Background: Chemotherapy as part of colorectal cancer management can cause death to immunologically active tumor cell, but also it has immune suppressive effect. Phyllanthus niruri Linn is known to has immunomodulatory effect. This study was intended to prove P. niruri Linn effect on infiltrating dendritic cells and Neutrophil/lymphocyte ratios (NLRs) in Sprague–Dawley rats with colorectal cancer which were given capecitabine chemotherapy. Methods: The study was randomized post–test only control group design. The samples were 39 Sprague–Dawley male rats, with body weight around 170–220 grams, induced by 1,2-dimetylhydrazine (DMH) 30 mg/kgBW once per week subcutaneously. On 9th,11th and 13th week, there were four induced rats sacrificed each week to detect colorectal cancer (CRC) development. On the 13th week, all of the 4 sacrificed rats developed colon cancer, so the induction had to be stopped. The rest of 27 induced rats were randomly divided into three groups: control-group (K) were left untreated (9 rats), group P1 (9 rats) were given Capecitabine and group P2 (9 rats) were given Capecitabine with combination of P. niruri Linn extract 13.5 mg/kgBW orally. After 17th week, all rats were terminated and tumor lesion of colon were processed to be paraffin blocks and were stained with HE for evaluating the NLRs, and immunohistochemistry (S100) for evaluating infiltrating dendritic cells. Data was analyzed by using Oneway-Anova-test and post-Hoc LSD-test. Considered significant if p was <0.05. Results: The mean±standard deviation of infiltrating dendritic cells showed increasing value in group P2 (62.11±31.35) compared to group P1 (52.78±29.24) though not statistically significant. The mean of NLRs also showed statistically significant elevation of value in group P2 (0.13±0.05) compared to group P1 (0.04±0.01). Conclusion: Extract of Phyllanthus niruri Linn increasing immunologic status through elevation of infiltrating dendritic cells and NLRs in animal model colorectal cancer with Capecitabine chemotherapy.     

Inhibitory effect of dietary monoglucosylceramide 1-O-beta-glucosyl-N-2'-hydroxyarachidoyl-4,8-sphingadienine on two different categories of colon preneoplastic lesions induced by 1,2-dimethylhydrazine in F344 rats

Sphingolipids display a wide spectrum of biological activities, including cell growth, differentiation and apoptosis. However, precise mechanisms by which these compounds exert anticancer or cancer-preventive effects are not known. In the present study, we evaluated the preventive efficacy of enriched dietary monoglucosylceramide 1-O-beta-glucosyl-N-2'-hydroxyarachidoyl-4,8-sphingadienine (G(1)CM) on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) and beta-catenin-accumulated crypt (BCAC) formation in F344 rats during initiation stage. We also examined whether G(1)CM affects cell proliferation and apoptosis in these lesions. Pure G(1)CM was isolated from rice bran. Forty-two rats were divided randomly into five experimental groups. Rats in groups 1-3 were given subcutaneous injections of DMH (40 mg/kg body weight) once a week for 2 weeks. One week before the first injection of DMH, rats in groups 2 and 3 were fed a diet containing 200 and 1,000 p.p.m. G(1)CM, respectively, for 5 weeks. Rats in group 4 were fed a diet containing 1,000 p.p.m. G(1)CM. Rats in group 5 were given the basal diet alone and served as untreated controls. The experiment was terminated 5 weeks after the start. Dietary G(1)CM at both doses (groups 2 and 3) significantly inhibited the induction of ACF and BCAC (P<0.001) when compared to group 1 treated with DMH alone. In groups 2 and 3, the proliferating cell nuclear antigen labeling indices of epithelial cells in ACF and BCAC were also lower than in group 1 (P<0.0001 for ACF, P<0.05 for BCAC). These results, that dietary G(1)CM has possible chemopreventive effects in the present short-term colon carcinogenesis bioassays, suggest that longer exposure may cause suppression of tumor development.     

Colorectal carcinoma in a rat model: suppression of tumour development and altered host immune status following treatment with anti B-lymphocyte serum

The rate of colonic tumour development and immune capability in rats whose B-lymphocyte function was suppressed by injections of rabbit anti-rat IgM and also given the carcinogen dimethylhydrazine (DMH) were studied. Four rat groups were arranged to receive either DMH + anti-IgM, DMH + normal rabbit serum (NRS), saline + anti-IgM, or saline + NRS. Tumour weight, blood and mesenteric lymph node B-lymphocyte numbers, in vivo allograft response, in vitro lymphocytotoxicity, and leucocyte migration inhibition response (LMI) were recorded fortnightly. Tumour induction was delayed in the DMH + anti-IgM (treated tumour) group, which developed less tumour than the DMH + NRS (untreated tumour) group (p less than 0.001). Spleen cell lymphocytotoxicities were depressed in treated rats when compared to either the saline + anti-IgM (treated control) rats or the untreated rats (P less than 0.02), whereas anti-IgM treatment suppressed lymphocytotoxicity responses in control rats (p less than 0.05). The untreated tumour rats were tumour immune by LMI; however, the treated tumour rats did not express this in vitro tumour immunity. The B-lymphocyte levels in the mesenteric lymph nodes of untreated tumour rats increased with tumour induction (p less than 0.05), whereas in the treated tumour rats B-lymphocyte levels were not similarly stimulated.