Aplicación del eest de la barra transversal modficado para evaluar ratas hemipparkinsonizadas.

La degeneracion nigroestriatal que caracteriza a la enfermedad de Parkinson (EP) es estudiada en modelos experimentales en roedores por inyeccion de 6-hidroxidopamina (6-OHDA). El presente estudio presenta una version modificada del test de la barra transversal (TBT) que permite la cuantificacion del deficit motor a traves de: tiempo que demora la rata en alcanzar una de las plataformas (latencia de escape, LE); tiempo que demora en caer de la barra (latencia de caida, LC); numero total de errores cometidos durante la ejecucion en cada barra (numero de errores, NE). La forma y el diametro de la seccion transversal de la barra se modificaron desde barras rectangulares y circulares de 2,5 cm de diametro hasta barras con esta misma forma y 1 cm de diametro respectivamente lo cual impuso la mayor dificultad a la ejecucion del test. Tres grupos de ratas Wistar fueron evaluados: no tratadas (n=15), lesionadas con 6-OHDA (n=14) y falsas operadas (n=14). Todas las variables estudiadas mostraron diferencias signifi-cativas entre ratas controles y hemiparkinsonizadas. Para todos los tipos de barras, las variables LE y NE se incrementaron mientras que la LC disminuyo significativamente en las ratas hemiparkinsonizadas en comparacion con las ratas controles. La LC mostro diferencias altamente significativas (p The nigrostriatal degeneration underlying Parkinson’s disease (PD) is commonly studied in experimental animals by injection of the neurotoxin 6-hydroxydopamine. The present study describes a modified version of a beam traversal test which allows the quantification of the motor deficit through the time spent to arrive to the platform once all four paws of the animals are in contact with the beam (escape latency, EL), the time spent before falling (tumbled down latency, TDL) and the number of errors (NE) committed for the animals in each beam. The shape and the diameter of the cross section of the beams were modified from rectangular and circular cross section with 2,5 cm of diameter to the same shape with 1 cm of diameter, which induced a high difficulty to the execution of the test. Three groups of Wistar rats were examined: untreated (n=15), lesioned with 6-hydroxydopamine (n=14), and sham-operated (n=14). All variables studied showed significant differences between control and hemiparkinsonian rats. The EL and the NE were increased and the TDL was decreased in hemiparkinsonian rats for all beams in comparison with control rats. In TDL the significant differences between groups were more evident (p