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.

Effect of curcumin on chemical intervention and mechanism of MNU-induced bladder cancer in rats / 中国实验动物学报

Objective To study the effect of curcumin on rat model of N-methylnitrosourea ( MNU) -induced bladder cancer and its mechanism. Methods One hundred SD rats were randomly divided into four groups:control group (n=10), model group (n=10), intervention group (n=40) and treatment group (n=40). Rats in the control group re-ceived intravesical infusion of distilled water. Rats in the other three groups were given MNU (1 mg/mL) in 2 mL saline at 2nd, 4th, 6th and 8th weeks to induce bladder cancer. In the model group, the rats were injected with distilled water in the bladder. The rats in the intervention group received 2 mL curcumin solution (400 μmol/L) at the 1st, 3rd, 5th, 7th and 9th weeks, and were sacrificed at the 11th week. In the model group, the rats were injected with distilled water in the bladder. In the treatment group, the rats had intravesical instillation of curcumin in the bladder (400 μmol/L, 2 mL) at 10, 12, 14, 16, and 18 weeks, and sacrificed at the 19th week. Bladder tissue samples were taken for pathological exami-nation using hematoxylin and eosin ( HE) staining. TUNEL staining assay was used to detect the apoptosis in tumor tissue. The expression of apoptosis-related proteins was detected by Western blot. Results The incidence of bladder cancer was 90% (9/10) in the model group, 12. 5% (5/40) in the intervention group and 92. 5% (37/40) in the treatment group at the 10th week, showing a significant difference between the intervention group and model group (P<0. 05), indicating an obvious interventional effect of curcumin on the bladder cancer. The incidence rate of bladder cancer in the treatment group was 78. 4% (30/37) at the 19th week, and compared with the 10th week before treatment, showing that curcumin can de-lay the recurrence of bladder cancer. TUNEL staining assay confirmed that curcumin significantly promoted the apoptosis in bladder cancer cells and inhibited their proliferation. The Western blot analysis showed that curcumin inhibited the activa-tion of NF-κB and effectively down-regulated the expression of NF-κB-regulated gene product. Conclusions Curcumin has a significant interventional effect on MNU-induced bladder cancer in the rat models. The mechanism may be through inhibi-tion of NF-κB activation and effective down-regulated NF-κB regulation of the gene products, and to regulate the expression of related proteins in bladder cancer, i. e. , inhibition of proliferation, induction of apoptosis, and further play a role of an-ti-cancer intervention and prevention of bladder cancer recurrence.

Effect of curcumin on chemical intervention and mechanism of MNU-induced bladder cancer in rats / 中国实验动物学报

Objective To study the effect of curcumin on rat model of N-methylnitrosourea ( MNU) -induced bladder cancer and its mechanism. Methods One hundred SD rats were randomly divided into four groups:control group (n=10), model group (n=10), intervention group (n=40) and treatment group (n=40). Rats in the control group re-ceived intravesical infusion of distilled water. Rats in the other three groups were given MNU (1 mg/mL) in 2 mL saline at 2nd, 4th, 6th and 8th weeks to induce bladder cancer. In the model group, the rats were injected with distilled water in the bladder. The rats in the intervention group received 2 mL curcumin solution (400 μmol/L) at the 1st, 3rd, 5th, 7th and 9th weeks, and were sacrificed at the 11th week. In the model group, the rats were injected with distilled water in the bladder. In the treatment group, the rats had intravesical instillation of curcumin in the bladder (400 μmol/L, 2 mL) at 10, 12, 14, 16, and 18 weeks, and sacrificed at the 19th week. Bladder tissue samples were taken for pathological exami-nation using hematoxylin and eosin ( HE) staining. TUNEL staining assay was used to detect the apoptosis in tumor tissue. The expression of apoptosis-related proteins was detected by Western blot. Results The incidence of bladder cancer was 90% (9/10) in the model group, 12. 5% (5/40) in the intervention group and 92. 5% (37/40) in the treatment group at the 10th week, showing a significant difference between the intervention group and model group (P<0. 05), indicating an obvious interventional effect of curcumin on the bladder cancer. The incidence rate of bladder cancer in the treatment group was 78. 4% (30/37) at the 19th week, and compared with the 10th week before treatment, showing that curcumin can de-lay the recurrence of bladder cancer. TUNEL staining assay confirmed that curcumin significantly promoted the apoptosis in bladder cancer cells and inhibited their proliferation. The Western blot analysis showed that curcumin inhibited the activa-tion of NF-κB and effectively down-regulated the expression of NF-κB-regulated gene product. Conclusions Curcumin has a significant interventional effect on MNU-induced bladder cancer in the rat models. The mechanism may be through inhibi-tion of NF-κB activation and effective down-regulated NF-κB regulation of the gene products, and to regulate the expression of related proteins in bladder cancer, i. e. , inhibition of proliferation, induction of apoptosis, and further play a role of an-ti-cancer intervention and prevention of bladder cancer recurrence.

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.

Observation on Epigallocatechin Gallate Treating the Bladder Tumor Induced by N-methyl-N-nitrosourea in Rats / 天津医药

Objective To investigate the therapeutic effect of epigallocatechin gallate (EGCG) on the bladder neo-plasm induced by N-methyl-N-nitrosourea (MNU) in Wistar rats. Methods Seventy-two female rats were randomly divid-ed into two groups, treatment group and control group. The rat model of bladder tumor was established by intravesical instilla-tion of MNU (2mL/time, once every two weeks) inside bladder. Rats in treatment group were given EGCG (2 mL/time, once/day), and control group were given the same volume of distilled water. Six rats were executed respectively at the 3rd, 5th, 7th, 9th, 11th and 13th week, and the bladder histopathological changes were studied in two groups. Results The untypical hyper-plasia was observed after 5 weeks. The bladder neoplasm was observed at the 11th week in control group. The bladder neo-plasm was not found in treatment group. There was a significantly lower pathological score in treatment group than that of control group except for the first two weeks (P＜0.05). Conclusion EGCG is effective for treatment of the bladder neo-plasm induced by MNU.

Down-regulation of interphotoreceptor retinoid-binding protein and up-regulation of recoverin expression in rats with N-methyl-N-nitrosourea-induced retinal damages / 中华眼底病杂志

Objective To investigate the effect of N-methyl-N-nitrosourea (MNU) on expressions of interphotoreceptor retinoid-binding protein (IRBP) and recoverin in rat retinal.Methods Thirty female Sprague-Dawley (SD) rats were randomly divided into five groups,including normal control group,and MNU treatment one day,three days,seven days and 10 days groups,each group had six rats.Rats in MNU-treatment groups received a single intraperitoneal injection of 40 mg /kg MNU,while rats in the normal control group received intraperitoneal injection of saline 5 ml/kg.Reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence were used to detect the retinal expression of IRBP and recoverin.Results RT-PCR results indicated that retinal IRBP levels decreased after MNU injection compared with normal control (P＜0.01),while recoverin levels increased (one day:P＞0.05; three days:P＜0.05; seven days:P＜0.5; 10 days:P＜0.05).Immunofluorescence assays demonstrated that normally IRBP protein is mainly in the inner and outer segments of photoreceptors.After MNU treatment,IRBP protein was detected in all retinal layers but much faint.Recoverin was expressed in the inner nuclear layer,inner plexiform layer and ganglion cell layer,and its expression was increased after MNU injection.Conclusion MNU suppresses IRBP expression and promotes recoverin expression in rat retina.

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...

Photoreceptor cell apoptosis of rat's retina induced by N-methyl-N-nitrosourea / 中华眼底病杂志

Objective To investigate the mechanism of the toxic effect of N-methyl-N-nitrosourea (MNU) on photoreceptor cell apoptosis of rat′s retina. Methods Thirty 50-day-old female Sprague-Dawley ( SD ) rats were intraperitoneally injected with MNU (60 mg/kg) and were put to death by dislocation of cervical vertebra 12, 24, 48, and 72 hours and 7 days after the injection, respectively. The photoreceptor cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) and transmission electron microscope. The expression of proliferating cell nuclear antigen (PCNA), vimentin and glial fibrillary acidic protein (GFAP) was detected at different time after injection by immunohistochemical methods. Results The apoptotic index of the retina in the posterior pole was (33.6?2.3)%, (46.5?5.7)%, (20.1?5.3)%, (8.2?3.6)% and (2.5?1.3% at the 12th, 24 th, 48 th, and 72nd hour and on the 7th day, respectively, after injection. Karyopyknosis was found in most photoreceptor cells 24 hours after injection. The expression of PCNA was found in internal granular layer and between internal granular layer and choroid 24 hours after injection, reached the peak after 72 hours, and reduced obviously after 7 days. The positive expression of GFAP and vimentin was found in internal and external granular layer 24 hours after injection, reached the peak after 72 hours, and reduced obviously after 7 days. Conclusion MNU may selectively lead the photoreceptor cell apoptosis and proliferation of M?ller cells.