Quercetin attenuates the development of 7,12-dimethyl benz(a)anthracene(DMBA) and croton oil-induced skin cancer in mice

To evaluate the chemopreventive potential of quercetin in an experimental skin carcinogenesis mouse model.Skin tumor was induced by topical application of 7,12-dimethyl Benz(a) anthracene(DMBA) and Croton oil in Swiss albino mouse.Quercetin was orally administered at a concentration of 200 mg/kg and 400 mg/kg body weight daily for 16 weeks in mouse to evaluate chemopreventive potential.Skin cancer was assessed by histopathological analysis.We found that quercetin reduced the tumor size and the cumulative number of papillomas.The mean latent period was significantly increased as compared to carcinogen treated controls.Quercetin significantly decreased the serum levels of glutamate oxalate transaminase,glutamate pyruvate transaminase,alkaline phosphatase and bilirubin.It significantly increased the levels of glutathione,superoxide dismutase and catalase.The elevated level of lipid peroxides in the control group was significantly inhibited by quercetin.Futhermore,DNA damage was significantly decreased in quercetin treated mice as compared to DMBA and croton oil treated mice.The results suggest that quercetin exerts chemopreventive effect on DMBA and croton oil induced skin cancer in mice by increasing antioxidant activities.     

Chemopreventive potential of an Indian medicinal plant (Tinospora cordifolia) on skin carcinogenesis in mice.

Tinospora cordifolia (Guduchi), an Indian medicinal plant, was used to explore antitumor promoting activity in a two-stage skin carcinogenesis model. For this purpose, mice were treated by single application of DMBA (100 microg/100 microl of acetone) and two weeks later promoted by croton oil (1% in acetone three times a week) until the end of the experiment (i.e., 16 weeks). Oral administration of the above extract at the preinitiational stage (i.e., seven days before and seven days after DMBA application; group IV), promotional stage (i.e., from the time of croton oil application; group V), and both pre- and postintiational stage (i.e., from the time of DMBA application and continued until the end of the experiment; group VI; on the shaven backs of the mice at the dose of 100 mg/kg body weight/day for 16 weeks) recorded significant reduction in tumor weight, tumor incidence in comparison to control (i.e., mice treated with DMBA and croton oil; group III). Furthermore, cumulative number of papillomas, tumor yield, tumor burden, and tumor weight showed significant reduction along with significant elevation of phase II detoxifying enzymes, and inhibition of lipid peroxidation in liver and skin in the animals administered with such plant extract concomitant to carcinogen exposure. Thus, the present data strongly suggests that the Tinospora cordifolia extract has anti-tumor potential in a two-stage skin carcinogenesis mouse model.     

Chemically induced skin carcinogenesis in mice and its prevention by Aegle marmelos (an Indian medicinal plant) fruit extract

This study assessed the chemopreventive potential of the Aegle marmelos plant on mouse skin tumorigenesis initiated by 7,12-dimethylbenz(a)anthracene (DMBA) and promoted by croton oil. A significant reduction in tumor incidence, tumor burden, tumor multiplicity, and the cumulative number of papillomas, along with a significant increase in the average latent period, was recorded in mice treated orally with A. marmelos extract (AME) at peri - and post-initiation phases (i.e., 7 days before DMBA application and continued until the end of the experiment) of papillomagenesis as compared with the carcinogen-treated controls. Furthermore, a significant increase in catalase activity, reduced glutathione and total proteins, and a depleted level of lipid peroxidation were observed in liver and skin of AME-treated animals as compared with the carcinogen-treated controls. Thus, the oral administration of AME, at a dose of 50 mg/kg body wt per day per animal, was found to be significantly effective in reducing skin tumors against chemical carcinogenesis in mice.     

Chemopreventive Activity of Methanol Extract of Melastoma Malabathricum Leaves in DMBA-Induced Mouse Skin Carcinogenesis

Background

Melastoma malabathricum L. Smith (family Melastomaceae) is a shrub that has been used by the Malay practitioners of traditional medicine to treat various types of ailments. The present study aimed to determine the chemopreventive activity of methanol extract of M. malabathricum leaves (MEMM) using the standard 7,12-dimethylbenz(α)anthracene (DMBA)/croton oil-induced mouse skin carcinogenesis model.

Materials and Methods

In the initiation phase, the mice received a single dose of 100µl/100 µg DMBA (group I–V) or 100µl acetone (group VI) topically on the dorsal shaved skin area followed by the promotion phase involving treatment with the respective test solutions (100 µl of acetone, 10 mg/kg curcumin or MEMM (30, 100 and 300mg/kg)) for 30 min followed by the topical application of tumour promoter (100µl croton oil). Tumors were examined weekly and the experiment lasted for 15 weeks.

Results

MEMM and curcumin significantly (p<0.05) reduced the tumour burden, tumour incidence and tumour volume, which were further supported by the histopathological findings.

Conclusion

MEMM demonstrated chemoprevention possibly via its antioxidant and anti-inflammatory activities, and the action of flavonoids like quercitrin.     

Piroxicam, indomethacin and aspirin action on a murine fibrosarcoma. Effects on tumour-associated and peritoneal macrophages.

Growth of a methylcholanthrene-induced fibrosarcoma in BALB/c mice was accompanied by an increase in the activation state of tumour-associated macrophages (TAM), as measured by their FcIgG receptor expression, phagocytic index and beta-glucuronidase levels. All of these parameters were markedly higher in TAM than in peritoneal macrophages (PM) derived from the same animal. On the other hand, PM from tumour-bearing mice showed lower activation parameters than PM from normal animals. We also studied the effect on tumour development of three inhibitors of prostaglandin synthesis: indomethacin, piroxicam and aspirin. Intraperitoneal administration of these drugs during 8 d was followed by the regression of palpable tumours. Indomethacin (90 mg/d) induced 45% regression, while with piroxicam (two 400 mg/d doses and six 200 mg/d doses) and aspirin (1 mg/d) 32% and 30% regressions, respectively, were observed. The growth rate of nonregressing tumours, which had reached different volumes by the end of the treatment, was delayed to a similar extent by the three anti-inflammatory non-steroidal drugs (NSAID). With respect to TAM, the treatment did not induce any significant change in their activation state, though both piroxicam and indomethacin increased slightly the TAM number. In contrast, NSAID administration was followed by a remarkable increase in the activation parameters of PM when compared with PM from tumour-bearing mice receiving no treatment. Indeed, these parameters were in some cases higher than those of PM from normal mice. The leukocytosis (60,000/microliters) with neutrophilia (80%) induced by tumour growth on peripheral blood leukocytes (PBL) was reversed by the treatment to values close to normal, in parallel with the reduction of tumour size. A drop in haematocrit was also noted which was most probably a consequence of tumour growth rather than of the treatment. This study reveals that the three NSAID tested have a remarkable antitumour activity, which correlates with the restoration of PM activity and PBL values.     

Transmaternal variation of the berenblum experiment with NMRI-mice

Summary DMBA which is applied transmaternally via the mothers milk can initiate tumour cells in the F-1 generation. Subsequent application of the tumour promoter TPA to the back skin of the young animals induced the formation of skin papillomas and carcinomas. Animals treated according to this scheme also developed malignant neoplasms in the other organs. Control animals treated with DMBA only, rarely developed tumours, whereas treatment with TPA alone had no effect.This variation of the Berenblum-experiment suggests that the transfer of carcinogens in human milk should be considered in addition to transplacental carcinogen transfer as a potential hazard to the developing human infant.Dedicated to Professor Dr. Heinrich Bredt on the occasion of his 70th birthday.     

Morphological characterization of cellular and extracellular components of 7,12 dimethylbenz[a]anthracene induced melanoma tumours.

Subcutaneous tumours were induced in castrated golden Syrian hamsters by 7,12 dimethylbenz[a]anthracene (DMBA), an agent known to produce papillomas and carcinomas. The morphological characteristics of the cellular and extracellular constituents of the chemically-induced tumours were indicative of melanoma. Tumours were induced by three injections of DMBA into the jugular vein over a 3 month period. Dermal tumour development within the dorsal integument and groin region ultimately projected into the epidermis and occurred during the 3 month period subsequent to the last DMBA injection. Suspect melanoma tumours were excised and processed for light microscopic (LM) and transmission electron microscopic (TEM) studies. Histochemical staining methods facilitated the characterization of the differentiated tumour components in this hamster melanoma model. The model presented could allow observations from initial melanoma transformation events through advanced stages of metastasis within a window of 7 months.     

Morphological characterization of cellular and extracellular components of 7,12 dimethylbenz[a]anthracene induced melanoma tumours

Subcutaneous tumours were induced in castrated golden Syrian hamsters by 7,12 dimethylbenz[a]anthracene (DMBA), an agent known to produce papillomas and carcinomas. The morphological characteristics of the cellular and extracellular constituents of the chemically-induced tumours were indicative of melanoma. Tumours were induced by three injections of DMBA into the jugular vein over a 3 month period. Dermal tumour development within the dorsal integument and groin region ultimately projected into the epidermis and occurred during the 3 month period subsequent to the last DMBA injection. Suspect melanoma tumours were excised and processed for light microscopic (LM) and transmission electron microscopic (TEM) studies. Histochemical staining methods facilitated the characterization of the differentiated tumour components in this hamster melanoma model. The model presented could allow observations from initial melanoma transformation events through advanced stages of metastasis within a window of 7 months.     

DMBA induced papillomas in congenitally athymic (nude) and hereditarily asplenic (Dh/+) mice: contrasts and comparisons with immunologically intact littermates.

Congenitally athymic (nude) and hereditarily asplenic (Dh/+) mice were painted with dimethylbenzanthracene (DMBA) to compare skin tumor development in these immunodeficient animals with their immunologically normal littermate controls. Papillomas were induced in all groups of mice. However, nude and Dh/+ mice were significantly more resistant than their normal littermates to tumor induction. Furthermore, the number of papillomas/mouse and the total tumor incidence were significantly greater in control mice and the latency period for tumor appearance was shorter and the tumor growth rate greater in normal mice compared to their immunodeficient littermates. Finally, nu/+ skin transplanted to nude mice and then painted with DMBA behaved in similar fashion as nude skin. These findings, when discussed in terms of target organs for DMBA, suggest a major role for the immune system in stimulating papilloma induction.     

Carcinogen-induced granulosa cell tumours in NZC/Bl mice

Old NZC/Bl mice have a high incidence (33%) of unilateral spontaneous granulosa cell tumours. A single topical application of 300 micrograms of 7, 12-dimethylbenz(a) anthracene (DMBA) to the skin at 6 wk of age substantially enhanced the incidence of granulosa cell tumours (95%), a high proportion of which were bilateral. Lesions were detected at a much younger age than in mice not exposed to the carcinogen. Endometrial changes were observed frequently, irrespective of DMBA treatment, and with or without granulosa cell tumours. These observations suggest that the incidence of endometrial hyperplasia, albeit substantially increased by DMBA treatment, is not necessarily dependent on granulosa cell tumour hormonal activity. Telangiectasia, principally affecting vessels in the ovary, uterus and small intestine, was a common finding in DMBA treated mice.     

Morphological and biological characteristics of mammary tumours induced by the direct application of DMBA powder to rat mammary glands

Summary Mammary tumours were induced by the direct dusting of 1 mg, 7,12-dimethylbenz(a)anthracene (DMBA) powder onto the mammary gland of both 30-day-old female and male Sprague-Dawley rats, and the tumours were examined histologically. Mammary tumours developed in 43/43 (100%) of the females 11 to 20 weeks after DMBA dusting and 16/23 (70%) of the males 18 to 28 weeks after dusting, while non-mammary spindle cell sarcomas occurred in 5/23 (22%) of the males 15 to 24 weeks after dusting. A variety of benign and malignant mammary tumours of epithelial and/or mesenchymal origin were induced, which are comparable to human mammary tumours. Different histological patterns were observed in different areas of the same tumours. Ovariectomy revealed hormone (ovary)-dependency in 10/17 (59%) of the tumours, revealing regressing epithelial and proliferating mesenchymal tumour elements on histological examination.This work is supported in part by grant-in-aid for cancer research 63010020, from the Ministry of Education, Science, and Culture, Japan     

Cross state-dependent retrieval between histamine and lithium

Histamine and lithium state-dependent (StD) retrieval of passive avoidance task and their interactions was examined in mice. The pre-training or pre-test intracerebroventricular (i.c.v.) injection of histamine (20 microg/mouse) impaired retrieval when it was tested 24 h later. In the animals, in which retrieval was impaired due to histamine pre-training administration, pre-test administration of histamine, with the same dose, restored retrieval. The H1 blocker, pyrilamine (20 microg/mouse, i.c.v.), but not the H(2) blocker; ranitidine prevented the restoration of retrieval by pre-test histamine. The pre-training (5 and 10 mg/kg) or pre-test (5 mg/kg) injection of lithium also impaired retrieval, when it was tested 24 h later. In the animals that received lithium (5 mg/kg) or histamine (20 microg/mouse) as pre-training treatment, administration of histamine, clobenpropit or lithium, respectively, resulted in restoration of memory retrieval. Neither pyrilamine nor ranitidine prevented the restoration of retrieval by pre-test lithium. In conclusion, histamine or lithium can induce state-dependent retrieval and a cross-StD exists between these drugs, which may be mediated through the inositol pathway.     

Modification of Immune Response by Cinnarizine

Effects of cinnarizine on immune response in mice were investigated. Mice were orally administered with cinnarizine and were immunized with sheep red blood cells (SRBC) intravenously. Numbers of plaque forming cells (PFC) to SRBC in spleen of these mice were assayed and delayed-type hypersensitivity (DTH) response to SRBC was measured. 1) PFC response in immunization with 5 × 10⁶ cells/mouse of SRBC was enhanced by administration of 25 mg/kg of cinnarizine, while the response in immunization with 5 × 10⁸ cells/mouse was suppressed by 25 to 200 mg/kg of cinnarizine. 2) From study on timing of administration, suppression of PFC response by 6.25 to 200 mg/kg of cinnarizine was observed at 24 hr. after the immunization. 3) 12.5 to 200 mg/kg of cinnarizine suppressed polyclonal B cell activation induced by lipopolysaccharide (LPS). 4) Colchicine induced suppressor T cell inactivation was prevented by administration of 50 mg/kg of cinnarizine and it was suggested that cinnarizine may induce suppressor T cells from the study of adoptive cell transfer system. 5) 50 mg/kg of cinnarizine showed the suppression of DTH response in expression phase, but not in induction phase. It was concluded that immune responses in mice were modified by cinnarizine.     

Murine oocyte destruction following intraovarian treatment with 3-methylcholanthrene or 7,12-dimethylbenz(a)anthracene: protection by alpha-naphthoflavone

Bilateral or unilateral intraovarian injection with the polycyclic aromatic hydrocarbons 3-methylcholanthrene (3-MC), or 7,12-dimethylbenz(a)anthracene (DMBA) destroys oocytes in C57BL/6N and DBA/2N mice. The threshold for small oocyte destruction following bilateral intraovarian treatment with 3-MC was between 0.1 and 1 microgram/ovary in both DBA/2N amd C57BL/6N mice. After intraovarian treatment with DMBA, a more potent ovotoxin, the thresholds for small oocyte destruction were between 0.01 and 0.1 microgram/ovary. Calculated ED50's for small oocyte destruction following bilateral intraovarian treatment with 3-MC were C57BL/6N, 0.33 micrograms/ovary; DBA/2N, 1.02 micrograms/ovary--for DMBA the ED50's were C57BL/6N, 0.11 micrograms/ovary; DBA/2N, 0.03 micrograms/ovary. Unilateral intraovarian treatment also destroyed oocytes in the treated ovary. Treatment with intraperitoneal alpha-naphthoflavone (ANF), a competitive inhibitor of polycyclic aromatic hydrocarbon metabolism by microsomal monooxygenases, inhibited oocyte destruction. Intraovarian treatment with ANF decreased oocyte destruction produced by intraovarian DMBA. These data suggest that both 3-MC and DMBA are indirect acting ovotoxins requiring metabolic activation before oocyte destruction occurs. In addition, these data also suggest that the ovary contains the enzymes necessary to biotransform xenobiotics like 3-MC and DMBA to ovotoxic metabolites. Metabolic activation of xenobiotics to reactive products within the ovary may represent a special threat to the integrity of oocyte DNA.     

Ultrastructure of streptozotocin — induced renal tumours in mice

Streptozotocin-induced tumours in the kidneys of experimental animals have been shown to be histologically similar to human renal cell carcinoma. We report the ultrastructural features of renal tumours induced in 15 mice by a single intravenous bolus of 2.5% Streptozotocin administered in a dose of 250 mg streptozotocin/kg mouse body weight. Animals were sacrificed 232–361 days after the administration of streptozotocin. On examination both kidneys from each animal contained 1–4 dysplastic tubules and 1–3 discrete tumours per kidney. Twelve dysplastic proximal convoluted tubules showing varying degrees of epithelial atypia and nine tumours exhibiting either a papillary or solid architecture were examined. Dysplastic epithelial cells and tumours of papillary and solid type exhibited complex cell borders with well-developed junctional complexes. The majority of cells contained surface microvilli, and in some cells microvilli-lined intracytoplasmic lumina were observed. Occasional dysplastic epithelial cells and tumour cells contained double-membrane vesicles 120–200 nm in diameter. These were similar to the intracytoplasmic vesicles characteristic of human chromophobe renal cell carcinoma. Intracytoplasmic collections of glycogen granules and flocculant protein were identified in both dysplastic and neoplastic cells, and where prominent they resulted in compression of cytoplasmic organelles. Coated vesicles were commonly observed. These were free within the cytoplasm and were also seen budding from strands of rough endoplasmic reticulum. The distribution of these vesicles suggested a role in protein transport from the rough endoplasmic reticulum. It is concluded that while streptozotocin-induced renal tumours have some ultrastructural features in common with human chromophobe renal cell carcinoma, the overall ultrastructural morphology differs significantly from that described for the various histological types of human renal cell carcinoma.     

头孢地秦在免疫抑制小鼠白念珠菌败血症中的作用

为观察头孢地秦 (cefodizime ,CDZ )在实验性免疫抑制小鼠白念珠菌败血症中的免疫调节作用及其在抗感染免疫中的综合作用 ,本文用环磷酰胺 (CTX )免疫抑制昆明种小鼠 ,分别腹腔注射CDZ 6 0 0mg/kg、 2 0 0mg/kg、 5 0mg/kg及头孢曲松 (cef triaxone ,CRO ) 2 0 0mg/kg× 7d。并在第 3天尾静脉注射白念珠菌 ,第 8天分别测定各组的炭廓清功能、血清溶血素的生成及T细胞亚群的变化。观察小鼠注射白念珠菌后的生存期并作生存分析。研究表明CDZ 6 0 0mg/kg、CDZ 2 0 0mg/kg组能明显提高CTX抑制的炭廓清功能 (P <0 0 5 ) ;CDZ各组亦能增加被CTX抑制的血清溶血素水平 (P <0 0 1) ;与CTX组相比 ,CDZ6 0 0mg/kg组明显提高CD4/CD8比值 (P <0 0 5 )。整体比较各组生存率 ,与其免疫调节功能基本一致。尾静脉注射白念珠菌后 ,CTX组 3d就有小鼠死亡 ,其平均生存期为 5d ,而CDZ 6 0 0mg/kg组、 2 0 0mg/kg组、 5 0mg/kg组最长生存期分别为 16d、17d和 12d ,其平均生存期分别为 12 8d、 11 7d和 9 6d ,明显高于免疫抑制组小鼠 (P <0 0 1)。而CRO组和免疫抑制组相比 ,差别无显著差异。说明CDZ能提高免疫抑制机体的免疫功能 ,并在抗感染免疫中发挥作用 ,提示其在临床感染治疗上可能具有重要的实际意义。     

Ultrastructure of ultraviolet radiation-induced hairless mouse skin carcinogenesis, with special reference to the epidermal-dermal junction

The ultrastructure of ultraviolet (UV)-induced skin pathology was studied in mice to complement previously reported gross and light microscopic findings, and to assess further the usefulness of the animal model for study of sunlight associated epidermal tumours in man. Hairless albino (HRA/Skh-1) mice were exposed to a minimal erythemal dose from a filtered light source emitting both UVA and UVB, approximating solar emission. Samples of normal and hyperplastic skin, pedunculated papillomas, carcinomas in situ and invasive squamous cell carcinomas were processed for transmission electron microscopy once their identity was confirmed by light microscopic examination. Keratinocyte pleomorphism became more marked and cell to cell contact diminished as malignancy developed. For papillomas, carcinomas in situ and invasive squamous cell carcinomas, there was a progressive disruption of the epidermal junction which became marked upon frank invasion. Most of the differences between the various categories of pathological change, therefore, were not absolute but rather of degree, supporting the notion that invasive squamous cell carcinoma represents an end stage for malignancy which may arise de novo, directly from hyperplastic skin, or proceed from other tumour types. The similarity in structure of the mouse tumours to comparable tumours in man supports the usefulness of the animal model and suggests that the results have implications for sunlight associated tumours in man.     

Regression of solid tumour using laser and 5-aminolevulinic acid in mice

Solid tumour reducing effect in Swiss albino mice induced with Dalton's Lymphoma Ascites tumour cells (DLA) and Ehrlich Ascites tumour cells (EA) was determined with the application of He-Ne and Nd:YAG lasers along with the photosensitising agent 5-Aminolevulinic acid (ALA). The experiment was designed with six groups and each group consisted of six animals. Animals in Groups I-III were injected with DLA cell lines and Groups IV-VI were injected with EA cell lines (1 x 10(6) in 0.1ml saline) subcutaneously in the right hind limb of mice to induce solid tumours. The tumour was further treated with photosensitiser induced laser therapy. The hyperthermic effect of Nd:YAG laser on tumour reduction was also evaluated. The results of the study suggest that the combination of He-Ne laser and 1 W Nd:YAG laser along with the photosensitiser 5-Aminolevulinic acid is a very effective therapeutic method for the treatment of tumour of DLA and EA cell lines. It is clear from the results that this mode of therapy very well depends on the type of tumour that has to be treated.     

Modulation of chemically initiated and promoted skin tumorigenesis in CD-1 mice by dietary glucarate

The efficacy of dietary calcium glucarate as a chemopreventative agent has been tested in the mouse skin tumorigenesis system. Skin tumorigenesis was initiated in mice of the CD-1 strain with 7,12-dimethylbenz(a)anthracene (DMBA), then promoted with twice weekly applications of 12-O-tetradecanoyl-phorbol-13-acetate (TPA) for 13 weeks. The mice were fed a regular chow diet, or a chow diet fortified with calcium glucarate (128 mmol/kg diet), or with equimolar calcium as calcium gluconate (negative calcium control). When mice were fed calcium glucarate throughout both the initiation and promotion phases papilloma formation was inhibited by over 30%. Transfer of these DMBA-initiated, TPA promoted CD-1 mice to chow diet after 13 weeks on the calcium glucarate-supplemented diet, resulted in an increase in the number of skin papillomas within 3 weeks to the level of those seen in control animals maintained exclusively on the chow diet. When calcium glucarate feeding was restricted to either the initiation or promotion phases, papilloma formation was inhibited by 25%. Dietary calcium gluconate had no effect on papilloma formation in the CD-1 mouse system, but increased the calcium concentration in the skin to the same extent as that of calcium glucarate. The data indicate that the elevation of the normally low levels of glucarate in the body through supplementation, results in a marked alteration in the retention, activity and/or metabolism of xenobiotics.