Actividad antitumoral de biopolímeros aislados de Vibrio sp. en cáncer de mama inducido en ratas / Antitumor activity of vibrio sp. isolated biopolymers in induced breast cancer in rats

RESUMEN Objetivo: Evaluar la actividad antitumoral del extracto crudo de biopolímeros aislados de la bacteria marina Vibrio sp. en cáncer de mama inducido por N-Methyl-N-nitrosourea (MNU) en ratas. Materiales y métodos: Se cultivó la bacteria marina Vibrio sp. durante siete días, luego se filtró, precipitó y concentró el sobrenadante crudo. Se administró una dosis única de MNU 50 mg/kg a 39 ratas Holtzman y fueron tratadas diariamente durante nueve semanas por vía oral: G1 (n=13): suero fisiológico 0,1 mL/100g; G2 (n=13): extracto crudo de biopolímeros de Vibrio sp. 20 mg/kg; G3 (n=13): tamoxifeno 100 mg/kg. El G4 (n=11) solo recibió suero fisiológico 0,1 mL/100g. Se valoró semanalmente el peso corporal y la aparición de tumores mamarios identificados mediante palpación; así como el examen histopatológico al final del tratamiento. Resultados: El 77% de las ratas del grupo G1 desarrollaron tumores a partir de la séptima semana en un promedio de 2,2 tumores por cada animal; en contraste al grupo tratado con el extracto crudo de biopolímeros y tamoxifeno; donde solo una rata (8%) en cada grupo desarrolló tumores y posterior a la semana nueve de la inducción (p=0,001). Los resultados histopatológicos sostienen que todos los tumores extirpados corresponden a adenocarcinoma ductal de mama con distintos patrones: sólido, papilar y quístico. Asimismo, se evidenciaron focos necróticos en el 30% de los tumores del grupo G1. Conclusión: El extracto crudo de biopolímeros aislados de Vibrio sp. presentan efecto antitumoral en cáncer de mama inducido en ratas.

ABSTRACT Objective: To evaluate the antitumor activity of the raw extract from biopolymers isolated from the Vibrio sp. marine bacteria in breast cancer induced by N-Methyl-N-nitrosourea (MNU) in rats. Materials and methods: The Vibrio sp. marine bacteria was cultured for seven days, then the raw supernatant was filtered, precipitated and concentrated. MNU was administered in a single dose of 50 mg/kg to 39 Holtzman rats and were daily treated for 9 weeks orally: G1 (n = 13): 0.1 mL/100 g of saline solution; G2 (n = 13): 20 mg/kg of raw extract from Vibrio sp. biopolymers; G3 (n = 13): 100 mg/kg of tamoxifen; G4 (n = 11) received no MNU and only 0.1 mL/100 g of saline solution. Body weight and the appearance of breast tumors identified by palpation were assessed weekly, as well as histopathological examination at the end of treatment. Results: Seventy-seven percent of the rats in the G1 group developed tumors from week 7 onwards in an average of 2.2 tumors per animal; in contrast to the group treated with the raw biopolymer extract and tamoxifen; where only one rat (8%) in each group developed tumors after week nine of induction (p = 0.001). The histopathological results support that all the removed tumors correspond to breast ductal adenocarcinoma with different patterns: solid, papillary and cystic. Likewise, necrotic foci were evidenced in 30% of the tumors of the G1 group. Conclusion: The raw extract of biopolymers isolated from Vibrio sp. present antitumor effect in breast cancer induced in rats.

Development of a Post-vitrectomy Injection of N-methyl-N-nitrosourea as a Localized Retinal Degeneration Rabbit Model

Since genetic models for retinal degeneration (RD) in animals larger than rodents have not been firmly established to date, we sought in the present study to develop a new rabbit model of drug-induced RD. First, intravitreal injection of N-methyl-N-nitrosourea (MNU) without vitrectomy in rabbits was performed with different doses. One month after injection, morphological changes in the retinas were identified with ultra-wide-field color fundus photography (FP) and fundus autofluorescence (AF) imaging as well as spectral-domain optical coherence tomography (OCT). Notably, the degree of RD was not consistently correlated with MNU dose. Then, to check the effects of vitrectomy on MNU-induced RD, the intravitreal injection of MNU after vitrectomy in rabbits was also performed with different doses. In OCT, while there were no significant changes in the retinas for injections up to 0.1 mg (i.e., sham, 0.05 mg, and 0.1 mg), outer retinal atrophy and retinal atrophy of the whole layer were observed with MNU injections of 0.3 mg and 0.5 mg, respectively. With this outcome, 0.2 mg MNU was chosen to be injected into rabbit eyes (n=10) at two weeks after vitrectomy for further study. Six weeks after injection, morphological identification with FP, AF, OCT, and histology clearly showed localized outer RD - clearly bordered non-degenerated and degenerated outer retinal area - in all rabbits. We suggest our post-vitrectomy MNU-induced RD rabbit model could be used as an interim animal model for visual prosthetics before the transition to larger animal models.

Differences between NMRI and DBA/2J mice in the development of somites and susceptibility to methylnitrosourea-induced skeleton anomalies

ABSTRACT The development of DBA/2J mouse strain embryos is nearly 12 h - or 6 somite pairs - delayed as compared to the outbred NMRI mouse embryos of the same age on gestation days (GD) 8-12. To evaluate inter-strain differences in susceptibility to teratogens, dams were treated with methylnitrosourea (MNU, 5 mg/kg body weight i.p.) on defined gestation days (NMRI: GD 9, 91/2 or 10; DBA/2J: GD 10 or 101/2). Skeletal anomalies produced by MNU on both mouse strains varied with the GD of treatment. The pattern of anomalies produced by MNU on a given GD markedly differed between the two mouse strains, yet they were similar -with a few exceptions- when exposures at equivalent embryonic stages are compared. Findings from this study indicated that strain-dependent differences in the developmental stage of mouse embryos of the same gestational age occur, a possibility that has been often neglected when inter-strain differences in susceptibility to developmental toxicants are interpreted.

Comparative study on the preventive effect of saffron carotenoids, crocin and crocetin, in NMU-induced breast cancer in rats

Objective: Crocin [Cro] and crocetin [Crt] are two widely known saffron carotenoids, which exert anticancer effects by different mechanisms. Here, we investigated and compared the preventive effect of Cro and Crt at the initiation and promotion stages of breast cancer induction in an animal model

Materials and Methods: In this experimental study, female Wistar albino rats were injected with three doses of N-methyl-N-nitrosourea [NMU]. The preventive intervention was done at different times for the initiation and promotion stages. Thus, Cro/Crt was administered by gavage 20 days before, or one week after, the first NMU injection, for the prevention at the initiation or promotion stages respectively. The treatment was repeated every three days, and continued up to the end of experiment. Tumor appearance was checked by palpation and some parameters were determined after sacrifice

Results: Tumor volume, latency period, and tumor number were significantly decreased in the rat groups treated with both saffron carotenoids for prevention at both the initiation and promotion stages. Tumor incidence was 77% due to NMU injection, which was decreased to 45 and 33% [on average] after Cro and Crt administration, respectively. In addition, enkephaline degrading aminopeptidase [EDA] was decreased significantly in the ovaries of the animals, however, changes in the brain were not significant

Conclusion: Crt/Cro showed a significant protective effect against the NMU-induced breast cancer in rats. However, Crt was more effective than Cro and prevention at the initiation stage was more effective than at the promotion stage

Nestin Expression in the Adult Mouse Retina with Pharmaceutically Induced Retinal Degeneration

The present study investigated the temporal pattern and cellular localization of nestin in the adult mouse retina with pharmaceutically induced retinal degeneration using N-methyl-N-nitrosourea (MNU). After a single intraperitoneal injection of MNU in 8-week-old C57BL/6 mice, the animals were sacrificed at 1, 3, 5, 7, and 21 days (n = 6, in each stage). The eyes were examined by means of immunohistochemical tests using nestin, ionized calcium-binding adaptor molecule (Iba-1), CD11b, F4/80, and glial fibrillary acidic protein (GFAP). Western blot analysis and manual cell counting were performed for quantification. Nestin expression was increased after MNU administration. Nestin+/Iba-1+ cells were migrated into outer nuclear layer (ONL) and peaked at day 3 post injection (PI). Nestin+/CD11b+ cells were also mainly identified in ONL at day 3 PI and peaked at day 5. Nestin+/F4/80+ cells were shown in the subretinal space and peaked at day 3 PI. Nestin+/GFAP+ cells were distinctly increased at day 1 PI and peaked at day 5 PI. The up-regulation of nestin expression after MNU administration in adult mouse retinal microglia, and monocyte/macrophage suggests that when retinal degeneration progresses, these cells may revert to a more developmentally immature state. Müller cells also showed reactive gliosis and differentiational changes.

Effect of N-Methyl-N-Nitrosourea on Helicobacter-induced Gastric Carcinogenesis in C57BL/6 Mice

BACKGROUND: The aim of this study was to investigate the effect of N-methyl-N-nitrosourea (MNU) treatment followed by chronic Helicobacter pylori SS1 and H. felis colonization on the stomachs of C57BL/6 mice. The role of MNU and Helicobacter species in gastric carcinogenesis was also elucidated. METHODS: A total of 69 C57BL/6 mice at 4 weeks of age were divided into 6 groups according to MNU treatment and H. pylori SS1 or H. felis infection. The mice were sacrificed at 21 and 50 weeks. The degree of inflammation was determined by histopathology. The levels of gastric mucosal myeloperoxidase, TNF-α, and interleukin-1β (IL-1β) were measured by ELISA. RESULTS: In the H. felis groups with or without MNU, the incidence of gastric tumors was 21.1% and 35.0% at 21 and 50 weeks, respectively. No gastric tumors were observed in all control mice. At 50 weeks, 37.5% of gastric adenoma cases were observed in the H. felis alone and MNU + H. felis groups. Furthermore, 12.5% of gastric adenocarcinoma cases were observed in the MNU alone and MNU + H. felis groups. The gastric mucosal IL-1β level was significantly higher in the MNU + H. felis group at 21 weeks and H. felis group at 50 weeks, respectively, than that for control mice (P < 0.05). However, the effect of MNU on H. pylori SS1-induced gastric carcinogenesis was low compared to that on H. felis. CONCLUSIONS: Administration of MNU before H. felis infection provokes severe inflammation through IL-1β, and eventually induces gastric cancer. However, the role of MNU in H. pylori SS1-induced gastric carcinogenesis model is minor.

Chemopreventive effects of garlic and mugwort mixture extract on Helicobacter pylori-associated mouse gastric carcinogenesis / 대한수의학회지

Garlic and mugwort have long been used in traditional medicine to prevent various diseases. Several in vitro studies have reported protective efficacies of garlic and mugwort in cases of gastric cancer. In the present study, we investigated the cancer preventive effects of garlic and mugwort mixture extract (GME) in a Helicobacter (H.) pylori-associated gastric carcinogenesis mouse model. To induce gastric cancer, C57BL/6 mice were treated with N-methyl-N-nitrosourea and H. pylori. Various concentrations of GME (0, 100, 500, and 1,000 ppm) were then fed to the mice for 38 weeks, after which the tumor tissues were examined for histopathology, mucin histochemistry and beta-catenin. The incidence of gastric tumors was significantly lower in the highest dose GME-treated mice (46.7%) than control mice (85.7%) (p < 0.05). The multiplicity and size of tumors were also significantly reduced by GME feeding in a dose-dependent manner (p < 0.01). Furthermore, GME suppressed the H. pylori-associated chronic inflammation measured by histologic grading of H. pylori density, chronic gastritis, glandular atrophy and intestinal metaplasia in non-tumorous gastric mucosae. Our data suggest that GME suppresses gastric tumorigenesis via suppression of H. pylori-associated chronic inflammation.

Chemopreventive effects of garlic and mugwort mixture extract on Helicobacter pylori-associated mouse gastric carcinogenesis / 대한수의학회지

Garlic and mugwort have long been used in traditional medicine to prevent various diseases. Several in vitro studies have reported protective efficacies of garlic and mugwort in cases of gastric cancer. In the present study, we investigated the cancer preventive effects of garlic and mugwort mixture extract (GME) in a Helicobacter (H.) pylori-associated gastric carcinogenesis mouse model. To induce gastric cancer, C57BL/6 mice were treated with N-methyl-N-nitrosourea and H. pylori. Various concentrations of GME (0, 100, 500, and 1,000 ppm) were then fed to the mice for 38 weeks, after which the tumor tissues were examined for histopathology, mucin histochemistry and beta-catenin. The incidence of gastric tumors was significantly lower in the highest dose GME-treated mice (46.7%) than control mice (85.7%) (p < 0.05). The multiplicity and size of tumors were also significantly reduced by GME feeding in a dose-dependent manner (p < 0.01). Furthermore, GME suppressed the H. pylori-associated chronic inflammation measured by histologic grading of H. pylori density, chronic gastritis, glandular atrophy and intestinal metaplasia in non-tumorous gastric mucosae. Our data suggest that GME suppresses gastric tumorigenesis via suppression of H. pylori-associated chronic inflammation.

Avaliação de alterações histopatológicas da próstata e séricas do PSA em ratos tratados com N-Metil-N-Nitrosureia e testosterona / Evaluation of histopathological changes in the prostate and serum PSA in mice treated with N-Methyl-N-Nitrosourea and testosterone

A testosterona tem sido cada vez mais usada em homens na fase do envelhecimento como prevenção e tratamento de doenças metabólicas, melhora do desempenho sexual, proteção cardiovascular e manutenção da cognição. Porém ainda há conflito sobre seus efeitos na próstata com relação às doenças benignas e malignas. O presente estudo avaliou o efeito do tratamento com duas formas de testosterona sobre carcinoma de próstata induzido por N-Metil-N-Nitrosureia (NMU) a partir de análises histopatológicas e séricas do antígeno prostático específico (PSA). Para tal foram utilizados 80 ratos Wistar jovens, sadios, divididos em dois grupos (40 animais cada) tratados ou não com NMU intraperitoneal. Cada grupo foi dividido em quatro subgrupos iguais e tratados durante 16 semanas: 1) tratado com cipionato de testosterona a cada sete dias via intramuscular; 2) tratado com cipionato de testosterona a cada 14 dias via intramuscular; 3) tratado com undecanoato de testosterona oral diariamente; 4) tratado com óleo mineral. Após 16 semanas e tratamento, os níveis do PSA não alteraram em nenhum grupo ou subgrupo e não houve desenvolvimento de tumores em nenhum deles. Portanto, as duas formas distintas de testosterona associada ao uso de NMU em curto espaço de tempo por via intraperitoneal não alteraram as dosagens séricas do PSA e não induziram a formação de tumores na próstata em ratos Wistar jovens e saudáveis. As alterações histopatológicas acinares encontradas nas próstatas foram projeção, secreção, congestão e inflamação, e as epiteliais foram: epitélio normal, redução do epitélio e redução na altura do mesmo. Tais achados colaboram para que outros estudos sejam realizados de maneira a orientar o uso de testosterona na prática clinica diária sem receio de indução do câncer na próstata.

Testosterone has been increasingly used in men during the aging process as prevention and treatment of metabolic diseases, improving sexual performance, cardiovascular protection and maintenance of cognition. But there are still conflicted about its effects in the prostate with respect to benign and malignant diseases. The present study evaluated the effect of treatment with two forms of testosterone on prostate carcinoma induced by N-methyl-N-nitrosourea (NMU) from pathological examinations and serum prostate-specific antigen (PSA). For this we used 80 young Wistar rats, healthy, divides into two groups (40 animals each) or not treated with intraperitoneal NMU. Each group was divided into four equal subgroups and treated for 16 weeks: 1) treated with testosterone cypionate every seven days intramuscularly, 2) treated with testosterone cypionate every 14 days intramuscularly, 3) treated with oral testosterone undecanoate daily, 4) treated with mineral oil. After 16 semanas and treatment, PSA levels did not change in either group or sub-group and no tumor development in any of them. Therefore, two different forms of testosterone associated with the use of NMU in short time intraperitoneally did not affect the serum PSA and did not induce tumor formation in prostate in young healthy rats. Acinar histopathological changes were found in the prostates projection, secretion, congestion and inflammation, epithelial and were normal epithelium, epithelial reduction and reduction in height thereof. These findings collaborate to further studies are performed in order to guide the use of testosterone in daily clinical practice without fear of inducing prostate cancer.

Expression Profiles of F4/80 and Nestin in Ocular Immune Cells Following Pharmaceutically Induced Retinal Degeneration in Adult Mice

PURPOSE: To evaluate the expression patterns of F4/80 and nestin in the ciliary body and the optic nerve following N-methyl-N-nitrosourea (NMU)-induced retinal degeneration in adult mice. METHODS: After intraperitoneal injection of MNU (60 mg/kg) in adult mice, the eyes were enucleated at 2, 4, 7 and 30 days. Hematoxylin and eosin (H&E) stain, terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) stain and immunohistochemical stains of F/80 and nestin were performed. RESULTS: After MNU treatment, the photoreceptors were destroyed by cell apoptosis. According to immunohistochemistry, F4/80 and nestin were not co-expressed in the control group, but F4/80 was expressed within the ciliary body and optic nerve in the MNU-treated group; the expression of nestin also increased. In the outer nuclear layer, F4/80 and nestin co-expressing cells were observed. CONCLUSIONS: In response to retinal damage, the F4/80 and nestin co-expressing cells migrated to the retina from the ciliary body and optic nerve and were activated.

High expression of cyclin D1 and p21 in N-nitroso-N-methylurea-induced breast cancer in wistar albino female rats

N-nitroso-N-methylurea [NMU] induces breast cancer in rodents, particularly in rats. This model of breast cancer is very similar to human breast cancer. As a continuation of our recent work, we investigated the expressions of cyclin D1 and p21 in NMU-induced breast cancer of Wistar Albino rats. In this experimental study, mammary carcinoma was induced in female Wistar Albino rats by a new protocol which included the intraperitoneal injection of NMU [50 mg/kg] at 50, 65, and 80 days of the animal's age. The animals were weighed weekly and palpated in order to record the numbers, location, and size of tumors. Subsequently tumor incidence [TI], latency period [LP], and tumor multiplicity [TM] were reported. About four weeks after the tumor size reached 1.5 cm[3], rats were sacrificed. Cyclin D1 and p21 expressions in tumors and normal mammary glands from normal rats were measured by reverse-transcription polymerase chain reaction [RT- PCR] and Western blot analysis. Statistical analysis of the data was performed using SPSS software version 16.0. The efficiency of tumor induction was 65%, LP was 150 days, and a TM of 1.43 +/- 0.53 per rat was noted. RT-PCR and Western blot data indicated significant [p<0.05] induction of both cyclin D1 and p21 expressions in rat mammary tumors compared with normal tissue from the control group. These results indicate an efficient mammary tumor induction protocol for this type of rat, which is accompanied by an increase in cyclin D1 and p21 expressions

Morphological and functional evaluation of an animal model for the retinal degeneration induced by N-methyl-N-nitrosourea / 대한해부학회지

The retinal degeneration (RD) is a general cause of blindness. To study its pathophysiology and evaluate the effects of new therapeutic agents before clinical trials, it is essential to establish reliable and stable animal models. This study evaluated a RD animal model in which blindness was induced by N-methyl-N-nitrosourea (MNU), a potent retinotoxin leading to apoptosis of photoreceptors. MNU was applied to the Sprague-Dawley rats by a single intraperitoneal injection in different doses (40, 50, and 60 mg/kg). The retinal functions were examined at 1 week after MNU injection by electroretinogram (ERG). Afterwards, each retina was examined by hematoxylin and eosin stain and immunohistochemistry with anti-glial fibrillary acidic protein antibody. Upon MNU injection of 40, 50 and 60 mg/kg, the ERG amplitude of a-waves showed significant reductions of 7, 26, and 44%, respectively, when compared to that of normal a-waves. The b-wave amplitudes were about 89, 65, and 58% of normal b-waves in the response to scotopic light stimulus. At 1 week, 2 weeks, and 4 weeks after MNU injection (50 mg/kg), all scotopic ERG components decreased progressively. In addition, degeneration of retinal neurons was observed in a time- and dose-dependent manner after MNU injection. Taken together, functional reduction following RD induced by MNU correlates with morphological changes. Thus, this RD rat model may be a useful model to study its pathophysiology and to evaluate the effects of new therapeutic agents before clinical trials.

The effects of Allium sativum (garlic) on N-Methyl-N-Nitrosourea induced transitional cell carcinoma in wistar rats: A preliminary study

OBJECTIVE: This study aimed to determine the effects of garlic (Allium sativum) on N-Methyl-N-Nitrosourea induced transitional carcinoma in Wistar rats. METHODOLOGY: Transitional cell carcinoma was induced in thirty male, age-matched Wistar rats (45-50 days old) through intravesical instillation of 0.1mL of N-Methyl-N-Nitrosourea. They were divided into five treatment groups (0.1 mL of NSS; 0.1 mL of Mitomycin C; 0.1 mL of aqueous garlic extract in 10 mg/kg, 20 mg/kg, and 40 mg/kg given daily for the duration of the study); with one rat sacrificed every week (starting two weeks from tumor induction) until all rats were sacrificed after one month. The urinary bladders of the rats were subjected to histopathologic examination by a single veterinary pathologist. One-way ANOVA was used to compare mitotic index, papillomatous growth and vascularization of the specimens at Day 14 (baseline), 21 and 28. A P-value of less than 0.05 was used to detect significant difference. RESULTS: Statistical analysis comparing mitotic index, papillomatous growth and vascularization showed no significant difference in the indices between the five treatment groups. It can be seen through that the P-value (0.144) for papillomatous growth was the smallest, which may indicate a trend towards a decrease in tumor growth at Day 28 for Mitomycin C and Garlic 40 mg/kg. CONCLUSIONS: This preliminary study showed a favorable trend towards decreased papillomatous growth in the MNU induced rat bladder carcinoma treated with aqueous extract of Garlic (Allium sativum) at a higher dose and longer duration of time.

Improvement of mouse model for thymic lymphoma induced by N-methyl-N-nitrosourea / 中国实验血液学杂志

The objective of this study was to elevate the tumorigenic rate of animal model with thymic lymphoma induced by N-methyl-N-nitrosourea (MNU) and to reduce the mortality of this mouse model. The injection regimen and experimental cycle were improved on the basis of previous experiments. The male and female C57BL/6 mice were injected by the intraperitoneal route with MNU solution at different dosages in the first week and the 4th week respectively. Following injection of MNU, the general features of the mice were observed. All mice were sacrificed for autopsy before the 24th experimental week. Complete gross examination was performed for detection of tumor masses. The pathologic and immunohistochemical methods were used to identify the origin and subtype classification of the neoplasm. The results showed that at the 25th week the incidence of thymic lymphoma in mice injected with MNU was 83.3% (55/66), the mortality was 7.6%. In conclusion, improving the program and changing the experimental cycle can increase the tumorigenic rate in the mouse model induced by MNU from 67.5% to 83.3% and reduce the mortality from 10% to 7.6%.

Establishment of an animal model with thymic lymphoma in mice / 中国实验血液学杂志

The objective of study was to establish an animal model with thymic lymphoma in mice induced by intraperitoneal injection of DNA alkylating agent N-methyl-N-nitrosourea (MNU). Male and female mice of the C57BL/6 strain were injected by the intraperitoneal route with MNU solution in a dosage of 50 mg/kg body weight. The injection was repeated at week 8. Following injection of MNU, the general status of mice was observed. All mice were sacrificed for autopsy at the 22nd experimental week. Complete gross examination was performed for detection of tumor masses. The results showed that at the 22nd week, the incidence of thymic lymphoma in MNU-treated animals was 67.5% (27/40). No significant sex difference in the incidence of thymic lymphoma was observed. In conclusions, an animal model with thymic lymphoma in mice can be established by twice intraperitoneal administration of MNU. The biological behavior of the induced tumors resembles to those of human thymic lymphoma derived from thymic T-cells.

Restraining effects of acupuncture on photoreceptor cell apoptosis in rats with retinitis pigmentosa induced by N-methyl-N-nitrosourea / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the effect of acupuncture on photoreceptor cell apoptosis in rats with retinitis pigmentosa induced by N-methyl-N-nitrosourea (MNU).</p><p><b>METHODS</b>Fifty-day-old female SD rats were established into model of retinitis pigmentosa by once intraperitoneal injection of 50 mg/kg MNU, and randomly grouped to the acupuncture group and the model group for observing the cell apoptosis in rats and compared with that in normal rats at the corresponding time points.</p><p><b>RESULTS</b>Acupuncture showed no effect on cell apoptosis at its peak of occurring, apoptotic phenomena still could be seen on days 5 and 7, but it was significantly less in the acupuncture group than in the model group (P < 0.01). Moreover, acupuncture showed a restraining effect on the up-regulation of caspase-3 activity.</p><p><b>CONCLUSION</b>Acupuncture can restrain the MNU induced apoptosis of photoreceptor cells, the effect is correlated, to a certain degree, with the status of the apoptosis occurrence.</p>

Pathological features and ultrastructure of N-methyl-N-nitrosourea (MNU)-induced thymic lymphomas in mice / 中国实验血液学杂志

The objective of study was to investigate the origin and to classify the subtype of N-methyl-N-nitrosourea (MNU)-induced thymic lymphomas in mice. Histopathologic, immunohistochemical and ultrastructural studies were performed to analyze the pathological features of the neoplasms. The results showed that the thymus in all cases became totally replaced by sheets of cells of the lymphoid series. All the tumors coexpressed CD3 and TdT. Transmission electron microscopic study showed the plasma membranes of malignant lymphoma cells were smooth. The nuclear profiles were usually regular, with varying percentage of convoluted nuclei. Few cell organoids were observed in cytoplasm. In conclusion, all the MNU-induced tumor classified by histopathologic, immunohistochemical and ultrastructural studies as precursor lymphoblastic lymphoma that were unquestionably related to the thymus origin and T-cell lineage.

Avaliação do potencial genotóxico e cancerígeno do lodo de estação de tratamento de esgoto (LETE) em sistemas experimentais in vivo / In vivo evaluation of the carcinogenic potential of sewage sludge from a urban wastewater treatment plant in experimental systems

A rápida oxidação da matéria orgânica dos solos tropicais é mais uma evidência da grande vantagem do uso de biossólidos como condicionadores, capazes de melhorar as características físicas, químicas e biológicas do solo com grandes reflexos na produtividade agrícola. Portanto, o presente projeto objetivou averiguar o potencial genotóxico e cancerígeno dos lotes do Lodo de Estação de Tratamento de Esgoto (LETE) gerado em uma ETE prédefinida na região da bacia hidrográfica Piracicaba, Capivari e Jundiaí (PCJ1). Estes dados poderão fornecer subsídios para a avaliação do risco das populações humanas e o meio ambiente expostas ao LETE. Foram utilizados 140 ratos Wistar machos com 8 semanas de idade, expostos, via ração, a concentrações de 10.000 e 50.000ppm de LETE, durante 6 e 8 semanas, com os iniciadores DEN (N-dietilnitrosamina) e DMH (1,2- dimetilhidrazina), conforme citado nos respectivos protocolos (Figuras 4 e 5). A avaliação toxicológica do lodo de esgoto desenvolvida pelo Núcleo de Avaliação do Impacto Ambiental Sobre a Saúde Humana (TOXICAM), enfocou os parâmetros toxicológicos, como seu potencial genotóxico, pelos testes do cometa e micronúcleo em sangue periférico e medula óssea e carcinogenicidade pelos ensaios de FCA e FHA. Os dois ensaios foram divididos em 4 grupos (FCA- GI=Controle Negativo, GII=Controle Positivo/DMH III=10.000ppmLETE e GIV=50.000ppmLETE); (FHAGI= Controle Negativo, GII=Controle Positivo/DEN, GIII=10.000ppmLETE e GIV=50.000ppmLETE). Entretanto, na 3ª semana foi realizada hepatectomia parcial em todos os animais dos respectivos grupos do ensaio de FHA. No teste do cometa foram utilizados 10 animais como controle positivo (controle interno - MNU-N-metil-N-nitrosourea), e 10 animais como controle negativo nos respectivos ensaios (FCA e FHA). Os testes em questão indicaram que o LETE não promove aumento do número de criptas...

Fast oxidation of organic matter on tropical soils is another evidence of the great advantage of using biosolids as conditioners once they are able to improve biological, chemical and physical characteristics of the soil with remarkable consequences on agricultural productivity. Therefore, the present project aimed at verifying genotoxic and carcinogenic potential plots of sludge from sewage treatment plants in a pre-defined watershed region at Piracicaba, Capivari and Jundiaí (PCJ1). These data may provide support to evaluate risks on human populations and the environment exposed to sludge from sewage treatment plants. In the study, 140 Wistar male rats, 8 weekold, were used. They were exposed, via chow, to a 10.000 and 50.000 ppm concentration of sludge from sewage treatment plants during 6 to 8 weeks with DEN initiators (diethylnitrosamine) and DMH (1,2-dimethylhydrazine) as mentioned in protocols (Figures 4 and 5). Toxicological evaluation of LETE developed by Center of Evaluation of Environmental Impact on Human Health (TOXICAM) focused toxicological parameters with its genotoxic potential by comet and micronucleus assays on peripheral blood and bone marrow in Wistar rats and carcinogenicity using ACF and AHF assays. Both assays were divided into 4 groups (ACF- GI=Negative Control, GII=Positive Control/DMH III=10.000ppmLETE and GIV=50.000ppmLETE); (AHF-GI=Negative Control, GII=Positive Positive/DEN, GIII=10.000ppmLETE and GIV=50.000ppmLETE). Therefore, on the 3rd week partial hepatectomy was performed in every animal from AHF assays respective groups. assays and to FCA comet test, using MNU (N-methyl-N-nitrosourea) as positive control. The tests in question indicated that the SS not promote increased number of aberrant crypts in the colon, number and area of foci of altered hepatocytes in the liver, lesions in DNA (comet), and also, significantly increased the frequency of micronucleus in...

Intestinal phenotypes of stomach cancers arising after Helicobacter pylori eradication in carcinogen-treated Mongolian gerbils.

AIMS: We have previously demonstrated the importance of gastric and intestinal phenotypic expression for the histogenesis of stomach cancer. However, the phenotypes of stomach cancers arising after Helicobacter pylori (Hp) eradication have hitherto remained unclear. We therefore examined a series of lesions occurring after Hp eradication in the Mongolian gerbil (MG) model. METHODS: Totals of 6 and 20 advanced glandular stomach cancers were evaluated in Hp-eradicated and Hp-infected MGs treated with N-methyl-N-nitrosourea (MNU-MGs), using several gastrointestinal epithelial phenotypic markers. The lesions were divided phenotypically into gastric (G type), gastric-and-intestinal mixed (GI type), intestinal (I type), and null (N type) phenotypes. RESULTS: All 4 differentiated type lesions in Hp-eradicated MNU-MGs were classified as G type, while both of the undifferentiated lesions exhibit the GI type. In Hp-infected MNU-MGs, the lesions were classified as 10 G, 8 GI, and 2 I types, with undifferentiated type lesions having more intestinal phenotypic expression than their differentiated counterparts (P< 0.01). CONCLUSIONS: Our data suggest that the differentiated stomach cancers exhibit the G type in Hp-eradicated MNU-MGs, suggesting that a kind of non-neoplastic G type gland may be precancerous. Intestinalization may still occur, especially in undifferentiated stomach cancers, even if Hp eradication is successful.

A comparative study on the protective effects of 17beta-estradiol, biochanin A and bisphenol A on mammary gland differentiation and tumorigenesis in rats.

Mammary tissue differentiation and tumorigenesis were studied in female rats following subcutaneous injection at 2, 4 and 6 days after birth with low or high doses of 17beta-estradiol (0.1 or 10 microg; E2), biochanin A (0.1 or 10 mg; BCA) or bisphenol A (0.1 or 10.0 mg; BPA). Half of the rats were killed on day 35 to analyze the terminal end bud (TEB), terminal duct (TD) and alveolar bud (AB) of the mammary tissue. The remaining rats were injected, ip, with a dose of 50 mg/kg of N-nitroso-N-methylurea (MNU) at 7 weeks of age and sacrificed 26 weeks later. The incidence and multiplicity of mammary tumors (MT) decreased among all three different treated groups, dose-dependently. However, the pattern of mammary gland differentiation varied. No significant difference was observed after E2 administration. TEB decreased dose-dependently in BCA treated groups and the number of TD and AB were suppressed significantly in BPA high dose group.