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En la estimación de la posible citotoxicidad de extractos o compuestos en proceso de prospección se emplean métodos de tinción celular como aproximación indirecta para la medición masa celular viable. En ensayos de citotoxicidad sobre las líneas celulares SiHa, MCF-7 y MKN-45 se comparan el método de tinción sulforoda-mina B (SRB), que es un ensayo de tipo terminal, con el uso de resazurina propuesta como poco tóxica para las células. La comparación de los métodos se hizo en términos de porcentaje de supervivencia donde se evaluó la sensibilidad de las líneas a tres compuestos sintéticos durante un periodo de tratamiento de 48 horas usando como referencia de actividad doxorrubicina HCl, un medicamento empleando en cáncer. Los datos obtenidos en los dos tipos de ensayos sometidos a una prueba de correlación mostraron que no hay diferencias significati-vas en ambos métodos permitiendo la comparación entre estos bajo las condiciones usadas. Palabras clave: citotoxicidad, correlación, resazurina, sulforodamina B. Abstract Cell staining methods are commonly used for estimating extracts or compounds’ potential cytotoxic activity when prospecting for indirect quantitative measurement of cell growth and viability. This work compared the sulphorhodamine B (SRB) staining method, which is a terminal cell density measuring assay, and the resazurin method, a cell proliferation assay which is supposed to be less toxic for the cell. The methods were compared in terms of percentage survival by evaluating MCF-7, MKN-45 and SiHa cell line sensitivity to three synthetic compounds using a 48-hour treatment period and doxorubicin HCl (a drug used in cancer treatment) as reference activity. A correlation test using the data obtained from the assays showed that there was no significant difference between the methods in the conditions used here. Key words: cytotoxicity, correlation, sulphorhodamine B assay, resazurin assay.

Para establecer la acción anticancerígena se han propuesto numerosas metodologías, principalmente enfocadas en la valoración de la citotoxicidad in vitro sobre líneas celulares neoplásicas derivadas de diferentes tipos de cáncer humano; sin embargo, gran parte de estas líneas celulares presentan el inconveniente de ser limitadas metabólicamente y, por lo tanto, pueden no resultar apropiadas para establecer la citotoxicidad de potenciales profármacos, al mostrar falsos negativos. La línea celular Hep-G2 se emplea en la detección de moléculas que requieran activación metabólica para ejercer una actividad biológica, por ser de origen hepático y por exhibir actividad de varias enzimas de la fase I y II, que juegan un importante rol en la activación y detoxificación de xenobióticos. Hep-G2 es utilizada como modelo para encontrar actividad citotóxica producida por 2-amino-1-metil-6-fenilimidazol[4,5-b]piridina (PhIP) y ciclofosfamida, en presencia o ausencia de agentes inductores. Para este análisis se mide indirectamente el número de células viables mediante los ensayos de reducción del MTT y de tinción con resazurina. Adicionalmente se evalúa la posibilidad de emplear sistemas de co-cultivos con otras líneas celulares para fortalecer la sensibilidad del método. Se observa una limitada citotoxicidad de PhIP y ciclofosfamida, por lo cual se establece un sistema de cocultivos, en donde las respuestas son similares a las obtenidas con cada línea celular independiente. Los resultados permiten proponer que Hep-G2, pretratada con algunos agentes inductores, muestra, aunque limitadamente, una sensibilidad por PhIP, similar a lo propuesto por diferentes autores.Several methodologies have been proposed in order to establish anticancer action, mainly focused on in vitro cytotoxicity valuation on neoplasic cell lines derived from human cancer. However, most of these cell lines are metabolically incompetent, restricting model sensibility and generating false negative answers. Hep-G2 cell line is widely used because of its high sensibility reflecting phase I and II activity of some enzymes of phase I and II, which play an important role in activation and detoxification of xenobiotics. In this study, Hep-G2 is used as a model to find cytotoxic activity produced by 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) and Cyclophosphamide, in presence or absence of inductor agents. This analysis was carried out by measuring indirectly viable number of cells with assays like MTT and resazurine staining. In addition, the possibility of co-cultures with other cell lines was evaluated according to strengthen method sensibility. Cytotoxicity of PhIP and cyclophosphamide was observed with the cellular staining methods. For this reason a co-culture system was established. The answer was similar to independent cell lines. These results propose that pre-treated Hep-G2 cells with some inductive agents show sensibility by PhIP as different authors postulate.

En la estimación de la posible citotoxicidad de extractos o compuestos en proceso de prospección se emplean métodos de tinción celular como aproximación indirecta para la medición masa celular viable. En ensayos de citotoxicidad sobre las líneas celulares SiHa, MCF-7 y MKN-45 se comparan el método de tinción sulforoda-mina B (SRB), que es un ensayo de tipo terminal, con el uso de resazurina propuesta como poco tóxica para las células. La comparación de los métodos se hizo en términos de porcentaje de supervivencia donde se evaluó la sensibilidad de las líneas a tres compuestos sintéticos durante un periodo de tratamiento de 48 horas usando como referencia de actividad doxorrubicina HCl, un medicamento empleando en cáncer. Los datos obtenidos en los dos tipos de ensayos sometidos a una prueba de correlación mostraron que no hay diferencias significati-vas en ambos métodos permitiendo la comparación entre estos bajo las condiciones usadas. Palabras clave: citotoxicidad, correlación, resazurina, sulforodamina B. Abstract Cell staining methods are commonly used for estimating extracts or compounds’ potential cytotoxic activity when prospecting for indirect quantitative measurement of cell growth and viability. This work compared the sulphorhodamine B (SRB) staining method, which is a terminal cell density measuring assay, and the resazurin method, a cell proliferation assay which is supposed to be less toxic for the cell. The methods were compared in terms of percentage survival by evaluating MCF-7, MKN-45 and SiHa cell line sensitivity to three synthetic compounds using a 48-hour treatment period and doxorubicin HCl (a drug used in cancer treatment) as reference activity. A correlation test using the data obtained from the assays showed that there was no significant difference between the methods in the conditions used here. Key words: cytotoxicity, correlation, sulphorhodamine B assay, resazurin assay.

Several methodologies have been proposed in order to establish anticancer action, mainly focused on in vitro cytotoxicity valuation on neoplasic cell lines derived from human cancer. However, most of these cell lines are metabolically incompetent, restricting model sensibility and generating false negative answers. Hep-G2 cell line is widely used because of its high sensibility reflecting phase I and II activity of some enzymes of phase I and II, which play an important role in activation and detoxification of xenobiotics. In this study, Hep-G2 is used as a model to find cytotoxic activity produced by 2-amino- 1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP) and Cyclophosphamide, in presence or absence of inductor agents. This analysis was carried out by measuring indirectly viable number of cells with assays like MTT and resazurine staining. In addition, the possibility of co-cultures with other cell lines was evaluated according to strengthen method sensibility. Cytotoxicity of PhIP and cyclophosphamide was observed with the cellular staining methods. For this reason a co-culture system was established. The answer was similar to independent cell lines. These results propose that pre-treated Hep-G2 cells with some inductive agents show sensibility by PhIP as different authors postulate.

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