Evaluation of methylmercury cytotoxicity at intestinal level

Abstract

Analysis of the RNA content of individual cells provides information on their translational capacity, which varies with cell differentiation and proliferation. In fact, because the rates of cell growth and proliferation are coupled, cellular or nuclear (nucleolar) RNA content indirectly serves as a marker of cell proliferation. The most common use of RNA measurement is in the discrimination of cycling from noncycling cells; RNA content is also a prognostic parameter in many malignancies. Two flow cytometric methods that simultaneously measure cellular RNA and DNA were developed. The first method is based on the use of the metachromatic dye acridine orange, which can differentially stain these nucleic acids. This method measures total cellular or nuclear RNA content and can be used in flow cytometers that have a single source of illumination. The second method uses a combination of fluorescent dyes, pyronin Y and Hoechst 33342. Only double-stranded RNA fluoresces when stained with pyronin Y. Simultaneous measurement of DNA and RNA utilizing Hoechst 33342 and pyronin Y requires the use of instruments having double excitation sources. Both methods are very sensitive to variations in dye concentration.