EVALUACIÓN DEL EFECTO DE DEXAMETASONA SOBRE EL CONSUMO DE GLUCOSA DE LAS CÉLULAS 3T3-L1.

Bajo las condiciones implementadas se procedió a evaluar el efecto de un glucocorticoide (dexametasona) sobre el consumo de glucosa por parte de los adipocitos 3T3-L1.

Según lo reportado en la literatura, los glucocorticoides ejercen un efecto negativo sobre la acción de la insulina cuando se administran por periodos prolongados, generando en las células un estado de resistencia a la insulina (Klein et al, 2002; Buren et al, 2008). Las concentraciones reportadas en los ensayos que se ha observado resistencia a insulina varían entre 10 y 100nM, y tiempos de exposición de 24, 48 y 72 horas (Garvey et al, 1987; Haber, 1992; Kajita et al, 2000). Teniendo en cuenta tales datos, se procedió a evaluar en nuestro modelo el efecto de la dexametasona sobre el consumo de glucosa estimulado por insulina.

El efecto inductor de resistencia a insulina del glucocorticoide se evidenció claramente en la Figura 7, donde se aprecia que dexametasona 10, 100, y 1000nM anuló completamente el efecto de insulina (1000 ó 2500 nM).

Por último, es esencial destacar aquí que lo más importante de este trabajo es que se aplicó un método enzimático-colorimétrico simple y económico para implementar un ensayo de cuantificación de consumo de glucosa en un modelo celular de adipocitos en cultivo, Adicionalmente, el ensayo implementado, se aplicó, de manera exitosa, a un modelo celular de resistencia a insulina inducida por glucocorticoides.

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1. Se implementó un nuevo ensayo no radiactivo, sencillo y económico para medir consumo de glucosa, en formato de microplacas (96 pozos), en células animales en cultivo.

2. Se iniciaron trabajos tendientes a desarrollar un modelo celular de resistencia a insulina, estableciendo las condiciones preliminares de tratamiento con dexametasona de los adipocitos 3T3-L1.

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Los resultados preliminares de este trabajo representan una clara innovación, y una importante alternativa a los procedimientos actuales utilizados en el estudio de la resistencia a insulina desde el punto de vista de los ensayos in vitro con modelos celulares. Las grandes ventajas del ensayo implementado, respecto de los métodos convencionales actuales, son su sencillez y economía, esto porque no se requieren equipos sofisticados de alto costo como los descritos anteriormente en este documento, ni tampoco la utilización de personal calificado en el manejo de tales instrumentos, haciéndolo apropiado para su utilización en países en vías de desarrollo donde es difícil contar con equipos sofisticados. La implementación del ensayo en un formato de microplacas de 96 pozos lo convierte en un ensayo susceptible de ser automatizado en un futuro cercano, y aplicable como método de rutina no sólo para el screening de nuevas moléculas con potencial sensibilizador a insulina (antidiabético), sino también como potencial método de diagnóstico en el laboratorio clínico, ya que podría proyectarse como un ensayo alternativo para evaluar la insulinoresistencia. Por último, puede llegar a ser un método de utilidad en los estudios tendientes a descifrar los mecanismos implicados en la fisiopatología de la diabetes mellitus tipo-2.

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