Efecto del aceite de Sacha Inchi (Plukenetia volubilis L.) en la carcinogénesis de colon inducida por 1,2–dimetilhidrazina en ratas Holtzman / Effect of Sacha Inchi oil (Plukenetia volubilis L.) on 1,2–dimethylhydrazine-induced colon carcinogenesis in Holtzman rats

Objetivos: Evaluar el efecto protector del aceite de Sacha Inchi (ASI) sobre el desarrollo de cáncer de colon (CC) inducido con 1,2–dimetilhidrazina (DMH) en ratas Holtzman. Materiales y métodos: Estudio experimental con 28 ratas albinas machos de la cepa Holtzman distribuidas al azar en 4 grupos: un grupo control positivo expuesto a DMH (C1), un grupo control negativo expuesto a ASI a 150 μL/kg/día (C2), y dos grupos experimentales expuestos a DMH con ASI a 150 μL/kg/día (E1) y ASI a 300 μL/kg/día (E2). La DMH se aplicó por 8 semanas y con un tiempo total de inducción de 22 semanas. Luego se realizó el análisis patológico mediante la identificación de lesiones tumorales cancerosas en los intestinos. El efecto protector se evaluó en base a las proporciones de ausencia de lesión en los grupos expuestos a DMH. Resultados: Se identificaron lesiones tumorales cancerosas en: dos especímenes del grupo C1, un espécimen del grupo E1 y dos especímenes del grupo E2. No se identificaron lesiones intestinales en el grupo C2. Las proporciones de ausencia de lesión fueron: en el grupo C1 de 75%, en el grupo E1 de 87,5% y en el grupo E2 de 75%. No se encontraron diferencias significativas (p>0,05). Conclusiones: No se evidenció un efecto protector significativo del ASI sobre el desarrollo de CC inducido con DMH en ratas Holtzman, respecto al grupo control.

Objectives: To evaluate the preventive effect of Sacha Inchi oil (SIO) on 1,2–dimethylhydrazine (DMH)-induced colon carcinogenesis (CC) in Holtzman rats. Materials and methods: Experimental study with 28 Holtzman male albino rats randomly distributed into 4 groups: a positive control group exposed to DMH (C1), a negative control group exposed to SIO at 150 uL/kg/ day (C2), and two experimental groups exposed to DMH with SIO at 150 uL/kg/day (E1) and SIO at 300 uL/kg/day (E2). The DMH was applied for 8 weeks and the total induction time was 22 weeks. Pathological examination was performed by identifying cancerous tumor lesions in the guts. The preventive effect was evaluated based on proportions of lack of lesion in the groups exposed to DMH. Results: Cancerous tumor lesions were identified in: two specimens of group C1, one specimen of group E1 and two specimens of group E2. No intestinal lesions were identified in group C2. The proportions of lack of lesion were: in group C1 of 75%, in group E1 of 87.5% and group E2 of 75%. No significant differences were found (p>0.05). Conclusions: It was not found a significant protective effect of SIO on DMH-induced CC in Holtzman rats, compared to control group.

Efecto quimioprotector del extracto alcaloideo de Melocactus bellavistensis (cactus globoso) sobre el cáncer de colon inducido con 1,2-dimetilhidrazina en ratas / Chemoprotective effect of the alkaloid extract of Melocactus bellavistensis against colon cancer induced in rats using 1,2-dimethylhydrazine

RESUMEN Objetivos Determinar la toxicidad y el efecto quimioprotector del extracto alcaloideo de Melocactus bellavistensis (cactus globoso) sobre el cáncer de colon inducido en ratas con 1,2 dimetilhidrazina (DMH). Materiales y métodos Se obtuvo el extracto alcaloideo de la parte carnosa de Melocactus bellavistensis, posteriormente, se realizó un ensayo de toxicidad aguda en 30 ratones de cepas Balb C57. Para evaluar su efecto quimioprotector se indujo el cáncer de colon en 45 ratas Holtzmann con DMH, según el siguiente diseño experimental: un grupo control con: polisorbato de sodio (PS) a 2 mL/kg y cuatro grupos con DMH 20 mg/kg más 0, 1, 5 y 10 mg/kg de extracto alcaloideo de Melocactus bellavistensis respectivamente. Resultados Con una muestra de 5 g de extracto alcaloideo se determinó una DL50 mayor a 1000 mg/mL en el ensayo de toxicidad aguda del extracto alcaloideo de Melocactus bellavistensis. Los resultados del efecto quimioprotector en los indicadores de estudio histopatológico revelaron que a las dosis de 5 y 10 mg/kg demostraron actividad antitumoral significativa en el cáncer de colon inducido por dimetilhidrazina en ratas con 100% de inhibición de neoplasia. Conclusiones En condiciones experimentales, el extracto de alcaloides de Melocactus bellavistensis demostró tener efecto quimioprotector en cáncer de colon inducido por dimetilhidrazina en ratas.

ABSTRACT Objectives To determine the toxicity and chemoprotective effect of the alkaloid extract of Melocactus bellavistensis against colon cancer induced in rats using 1,2-dimethylhydrazine (DMH). Materials and methods The alkaloid extract was obtained from the fleshy part of M. bellavistensis, and an acute toxicity test was then carried out on 30 mice of the Balb C57 strain. To assess its chemoprotective effect, colon cancer was induced in 45 Holtzman rats using DMH according to the following experimental design: one control group received 2 mL/kg sodium polysorbate, and four groups received 20 mg/kg DMH plus 0, 1, 5, or 10 mg/kg M. bellavistensis alkaloid extract. Results With a sample of 5 g of alkaloid extract, an LD50 greater than 1000 mg/mL was determined in the acute toxicity test. Histological indicators revealed that the 5 and 10 mg/kg doses had significant anti-tumor activity with 100% neoplasia inhibition against DMH- induced colon cancer in rats. Conclusions Under experimental conditions, the alkaloid extract of M. bellavistensis has a chemoprotective effect against DMH-induced colon cancer in rats.

Comparative study of 1, 2-dimethylhydrazine and azoxymethane on the induction of colorectal cancer in rats / Estudo comparativo das substâncias 1, 2-dimetil-hidrazina e azoximetano na indução de câncer colorretal em ratos

The induced colorectal carcinogenesis in rodents has a long history and currently uses the substances 1,2-dimethylhydrazine and azoxymethane. Objective: The aim of this study was to compare the inductive effect of the substances azoxymethane and 1,2-dimethylhydrazine in colorectal carcinogenesis. Method: 30 randomly chosen male Wistar rats were divided into four groups. G1 group was treated with 1,2-dimethylhydrazine and C1 was its control group; G2 group was treated azoxymethane and C2 was its control group. The animals were weekly weighed until euthanasia, when their intestines were removed, processed and analyzed by an experienced pathologist. Results: Among the control groups (C1 and C2) no histologic changes were observed; moderate dysplasia was detected in G2 group; hyperplasia, mild dysplasia, severe dysplasia and carcinoma were observed in G1 group. When this study compared the cost of the substances, 1,2-dimethylhydrazine was more than 50 times less expensive than azoxymethane. Conclusion: Azoxymethane is able to promote histological changes consistent with colorectal carcinogenesis. 1,2-Dimethylhydrazine produced neoplasia and dysplasia, and, compared to the azoxymethane, was more efficient in the induction of colorectal cancer. (AU)

A carcinogênese colorretal induzida em roedores tem longa história e utiliza, atualmente, as substâncias 1,2 dimetil-hidrazina (DMH) e azoximetano (AOM). Objetivo: Comparar o efeito indutivo das substâncias AOM e DMH para o câncer colorretal (CCR). Método: 30 ratos Wistar machos foram randomizados em quatro grupos. O grupo G1 foi inoculado com DMH, o grupo C1 foi seu controle; G2 recebeu o AOM e C2 foi seu controle. Os animais foram pesados semanalmente até a eutanásia, quando tiveram seus intestinos retirados, processados e analisados por um patologista experiente. Resultados: Os animais dos grupos de controle apresentaram tecido colorretal normal e os animais do grupo G2 apresentaram um padrão de displasia moderada. Nas lâminas do grupo G1, foram encontradas regiões de hiperplasia, displasia leve, displasia grave, e carcinoma. Comparado o custo das substâncias AOM e DMH, este último teve um preço mais de 50 vezes menor ao do AOM. Conclusão: AOM é capaz de promover alterações histológicas compatíveis com a carcinogênese colorretal. DMH produziu neoplasia e displasia grave e, comparada ao AOM, foi mais eficiente na indução do câncer colorretal. (AU)