Efecto anestésico local del extracto glandular salival del hematófago Rhodnius prolixus

Abstract

Los Triatominos son insectos hematófagos, vectores del Trypanosoma cruzi, causante de la enfermedad de Chagas. Estos insectos secretan una saliva compuesta de sustancias con múltiples propiedades biológicas, entre ellas la capacidad de anestesiar eficazmente la zona de donde se alimentan. Existe solo un estudio que describe esta propiedad en la saliva de los Triatominos, y plantea la posibilidad que este componente anestésico actúe de forma similar a los anestésicos locales conocidos actualmente. Objetivos: Este estudio está diseñado con el objetivo de obtener extracto glandular salival procedente de Rhodnius prolixus y evaluar su efecto anestésico local. Materiales y métodos: Se usaron Rhodnius prolixus, criados en 26 . 2ºC. y HR70%. Posteriormente se obtuvo un extracto glandular salival, el cual se utilizó para evaluar el efecto anestésico en un modelo murino. Se estudiaron 9 ratones, en los cuales se infiltro el extracto glandular a nivel subcutáneo en el muslo derecho y una solución control en el muslo izquierdo, evaluando la respuesta al dolor periódicamente. Resultados y discusión: Se observó entre el minuto 15 y 20 el efecto anestésico máximo; con una latencia media del efecto anestésico de 8,6 minutos (Desv. Estándar 5,6 minutos) y una duración máxima media del efecto de 36,7 minutos (Desv. Estándar 12,1 minutos). Adicionalmente se calculó la diferencia de proporción de presentación de dolor, con una diferencia de proporción máxima de -0,75 al minuto 10, IC 95% (-1.05 a -0,44), p= 0.02, al minuto 15 de -0,75, IC 95% (-1.05 a -0,44), p= 0.02, y al minuto 20 de -0,75, IC 95% (-1.07 a -0,43), p=0,03. Conclusiones: En este estudio experimental de laboratorio se comprueba en un modelo murino el efecto anestésico local del extracto glandular salival del hematófago Rhodnius prolixus, siendo el primer paso en la posible caracterización y aislamiento de una nueva molécula anestésica local.

Abstract: The Triatomines are heamatophagous insects hosts and vectors for Trypanosoma cruzi. These insects secrete saliva formed by a wide variety of substances with properties that facilitate their feeding process. In addition to these properties, the argument exists that the saliva of this insect may contain a highly effective local anesthetic molecule, because, in spite of being large insects, they produce a painless bite and may last long periods sucking blood without being perceived. Regarding this theoretical approach, there is one study which shows that the saliva of Triatoma infestans could have an inhibitory effect on Na+ channels, which could reduce the generation and duration of the nervous action potential, consequently reducing local sensitivity, a manner similar to currently known local anesthetics. Given the above, and considering that any molecule from these insects having the anesthetic action has been isolated and characterized, it is of great interest to make research on this subject. Objective: To obtain a glandular extract from Rhodnius prolixus and check its local anesthetic effect in an animal model. Materials and Methods:Rhodnius prolixus insects were used; subsequently the salivary glands were removed and a glandular extract was obtained. To test whether this glandular extract had local anesthetic effect, 9 mice were used, to which the glandular extract was administered subcutaneously in the right leg and control solution was administered in the left leg, making painful stimulus with fine-tipped tweezers periodically in both legs and evaluating the response to pain. Results and Discussion:The maximum anesthetic effect was observed between minute 15 and 20; with a mean latency of the anesthetic effect of 8.6 minutes and a maximum effect duration mean of 36.7 minutes. In addition, the difference in the proportion of pain is calculated, with a maximum ratio difference of -0.75 minute 10, 95% CI (-1.05 to -0.44), p = 0.02, at minute 15 of -0.75, 95% CI (-1.05 to -0.44), p = 0.02, and at minute 20 of -0.75, 95% CI (-1.07 to -0.43), p = 0.03. Conclusion(s):In this experimental laboratory study, the local anesthetic effect of the salivary glandular extract of the hematophagous Rhodnius prolixus is demonstrated in a murine model, being the first step in the possible characterization and isolation of a new local anesthetic molecule.