Efecto del estrés crónico y de la masticación sobre los niveles séricos de interleuquina-6 e interferón-gama / Effect of chronic stress and chewing on serum interleukin-6 and interferon-gamma levels

Introducción: el estrés crónico afecta el equilibrio inmunológico alterando los niveles séricos de interleuquina-6 (IL-6) e interferón gama (INF-γ), dicha alteración afecta al sistema nervioso y al comportamiento humano. La masticación adecuada disminuiría dichos efectos. El objetivo del estudio fue determinar el efecto del estrés crónico y de la masticación sobre los niveles séricos de IL-6 e INF-γ. Métodos: experimento donde se emplearon 64 ratones Balb/c de 8 semanas de edad. Se dividieron en 4 tratamientos: Grupo NE: Masticación normal + estrés, Grupo N: masticación normal sin estrés, Grupo DE: Masticación deficiente + estrés, Grupo D: masticación deficiente sin estrés. Mediante test de ELISA se midió IL-6 e IFN-γ alfinal de la 4ta y de la 8va semana de tratamiento. Resultados: tanto la IL-6 como el IFN-γ fueron mayores en el grupo DE (p<0,05) al final de la 4ta semana. Al evaluarlos al término de la 8va semana se observó que en el grupo NE se incrementó la IL-6 respecto al resto de grupos (p<0,0001), y en el grupo DE fue donde se encontró mayor cantidad de IFN-γ (p<0,0001). Conclusión: el estrés crónico y la masticación deficiente incrementan los niveles séricos de IL-6 e IFN-γ. En cambio, la adecuada masticación disminuye el nivel de tales citoquinas al final de la cuarta semana de tratamiento.

Introduction: chronic stress affects the immune balance by altering the serum levels of interleukin-6 (IL-6) and gamma interferon (INF-γ), this alteration affects the nervous system and human behavior. Appropriate chewing would lessen these effects. The aim of this study was to determine the effect of chewing and chronic stress over serum levels of IL-6 and INF-γ. Methods: experiment in which 64 Balb/C mice of 8 weeks of age were used, they were divided into 4 treatments: Group NE: Normal chewing + stress, Group N: normal chewing without stress, Group DE: Chewing poor + stress, Group D: poor chewing without stress. IL-6 and IFN-γ were measured by ELISA after 4 and 8 weeks of treatment. Results: both IL-6 and IFN-γ were higher in the DE group (p < 0,05) at the end of fourth week of treatment. When evaluating the animals at the end of the eighth week of treatment, it was observed that in the NE group, the IL-6 was increased with respect to the rest (p < 0,0001) and the DE group showed more IFN-γ (p < 0,0001). Conclusion: stress and poor chewing increase serum IL-6 and IFN-γ. In contrast, appropriate chewing decreases the effects of stress on the increase of such cytokines at the end of the fourth week of treatment in animals.

Determinación de la temperatura de respuesta nociceptiva sobre la cola de ratones albinos de la cepa Balb/c / Determination of the temperature causing a nociceptive response in the tail of albino BALB/c mice

Introducción: Los diseños para determinar la respuesta nociceptiva en roedores son de gran utilidad en neurología y en neurociencias experimentales. El paradigma de inmersión de la cola de ratón en agua temperada es uno de los más empleados para evaluar dicha respuesta; sin embargo, existe amplia variación en la temperatura utilizada en las diversas investigaciones. Resulta sumamente útil determinar la temperatura que produce una mejor respuesta nociceptiva sobre la cola de ratones de la cepa Balb/c.MétodosSe emplearon 8 ratones machos Balb/c de 2 meses de edad. Un beaker de 14 cm de alto se llenó de agua hasta 13 cm. Partiendo desde los 36 °C se empezó a sumergir la cola del animal dentro del recipiente. Se comenzó a elevar en 1 °C el agua hasta encontrar las temperaturas que produzcan las respuestas nociceptivas. Dicha respuesta se determinó contabilizando el tiempo que el ratón tardó en sacudir su cola retirándola del agua.ResultadosLos ratones empezaron a sacudir su cola a los 51 °C (6 de los 8 roedores). El total de la muestra retiró su cola del agua a los 54, 55 y 56 °C en el tiempo promedio de 8,54, 7,99 y 5,33 s, respectivamente. Al aplicar ANOVA a los tiempos de las 3 temperaturas señaladas se obtuvo el valor F = 2,8 y p = 0,123.ConclusionesEl tiempo de respuesta fue similar estadísticamente ante las temperaturas de 54, 55 y 56 °C; sin embargo se encontró menor dispersión de los datos ante esta última. (AU)

Introduction: Designs for determining nociceptive response in rodents are of great use in neurology and experimental neuroscience. Immersing mice's tails in warm water is one of the most widely used procedures to evaluate this response; however, a wide range of temperatures are used in different studies. Knowing the temperature that produces a powerful nociceptive response in the tail of BALB/c mice is extremely useful.MethodsEight 2-month-old male BALB/c mice were used. A 14-cm high beaker was filled with water up to 13 cm. The animals’ tails were immersed in the container with a starting temperature of 36 °C. The water temperature was raised in 1 °C increments until we identified the temperatures that produced nociceptive responses. That response was determined by counting the time taken before the mouse shook its tail to remove it from the water.ResultsSix of the 8 mice began shaking their tails at the temperature of 51 °C. All animals removed their tails from the water at the temperatures of 54 °C, 55 °C, and 56 °C, taking a mean time of 8.54, 7.99, and 5.33 seconds, respectively. ANOVA applied to the response times for each of the 3 temperatures indicated revealed a value of F=2.8 (P=.123).ConclusionsThe response time was statistically similar for the temperatures of 54 °C, 55 °C, and 56 °C; however, the data were less dispersed for the latter temperature. (AU)

Determination of the temperature causing a nociceptive response in the tail of albino BALB/c mice.

INTRODUCTION: Designs for determining nociceptive response in rodents are of great use in neurology and experimental neuroscience. Immersing mice's tails in warm water is one of the most widely used procedures to evaluate this response; however, a wide range of temperatures are used in different studies. Knowing the temperature that produces a powerful nociceptive response in the tail of BALB/c mice is extremely useful. METHODS: Eight 2-month-old male BALB/c mice were used. A 14-cm high beaker was filled with water up to 13cm. The animals' tails were immersed in the container with a starting temperature of 36°C. The water temperature was raised in 1°C increments until we identified the temperatures that produced nociceptive responses. That response was determined by counting the time taken before the mouse shook its tail to remove it from the water. RESULTS: Six of the 8 mice began shaking their tails at the temperature of 51°C. All animals removed their tails from the water at the temperatures of 54°C, 55°C, and 56°C, taking a mean time of 8.54, 7.99, and 5.33seconds, respectively. ANOVA applied to the response times for each of the 3 temperatures indicated revealed a value of F=2.8 (P=.123). CONCLUSIONS: The response time was statistically similar for the temperatures of 54°C, 55°C, and 56°C; however, the data were less dispersed for the latter temperature.

Influencia del estrés crónico y de la masticación sobre el dolor / Influence of chronic stress and chewing over the pain

Resumen Introducción: El estrés crónico y la masticación afectan a la respuesta dolora; sin embargo, hay escasos conocimientos sobre la relación entre dichas variables. Objetivo: Determinar la influencia del estrés crónico y la masticación sobre la respuesta al dolor. Métodos: 32 ratones albinos machos de 8 semanas de edad de la cepa Balb/c se dividieron en 4 grupos iguales: Grupo N: masticación normal sin estrés; Grupo NE: Masticación normal + estrés, Grupo D: masticación deficiente sin estrés y Grupo DE: Masticación deficiente + estrés. Se evaluó la respuesta al estímulo doloroso mediante el test de retirada de la cola ante un estímulo térmico. Resultados: Mediante Anova se compararon los 4 grupos experimentales a la décima segunda y décima sexta semana de vida de los ratones, obteniéndose un valor de p = 0,982 y p = 0,176; respectivamente. Mediante t de student para muestras relacionadas se comparó la variación de la respuesta al dolor; se obtuvo un valor de p = 0,52; p = 0,17; p = 0,84 y p = 0,069 para el grupo N, NE, D y DE respectivamente. Conclusión: El estrés crónico y la masticación no modifican la respuesta al dolor en ratones de la cepa Balb/c.

Abstract Introduction: Chronic stress and mastication affect the response to pain; however, there is little knowledge about the relationship between these variables. Objective: Determine the influence of chronic stress and mastication on the response to pain. Methods: thirty-two 8-week-old male Balb/c mice were used. The sample was divided into 4 equal groups: Group N: normal mastication without stress; Group NE: Normal chewing + stress, Group D: deficient chewing without stress and Group DE: Poor chewing + stress. The response to the painful stimulus was evaluated through the tail withdrawal assay due to a thermal stimulus. Results: By comparing the 4 experimental groups to the fourth and the eighth week through the ANOVA test yielded a value of p = 0.982 and p = 0.176; respectively. By applying the 't' student, within each group, in comparison of the variation of the pain response between the fourth and eighth week, the values ​​of p = 0.52; p = 0.17; p = 0.84 and p = 0.069 were obtained for the group N, NE, D and DE respectively. Conclusion: Chronic stress and mastication do not modify the response to pain in albino Balb/c mice.

Determination of the temperature causing a nociceptive response in the tail of albino BALB/c mice. / Determinación de la temperatura de respuesta nociceptiva sobre la cola de ratones albinos de la cepa Balb/c.

INTRODUCTION: Designs for determining nociceptive response in rodents are of great use in neurology and experimental neuroscience. Immersing mice's tails in warm water is one of the most widely used procedures to evaluate this response; however, a wide range of temperatures are used in different studies. Knowing the temperature that produces a powerful nociceptive response in the tail of BALB/c mice is extremely useful. METHODS: Eight 2-month-old male BALB/c mice were used. A 14-cm high beaker was filled with water up to 13 cm. The animals' tails were immersed in the container with a starting temperature of 36°C. The water temperature was raised in 1°C increments until we identified the temperatures that produced nociceptive responses. That response was determined by counting the time taken before the mouse shook its tail to remove it from the water. RESULTS: Six of the 8 mice began shaking their tails at the temperature of 51°C. All animals removed their tails from the water at the temperatures of 54°C, 55°C, and 56°C, taking a mean time of 8.54, 7.99, and 5.33seconds, respectively. ANOVA applied to the response times for each of the 3 temperatures indicated revealed a value of F=2.8 (P=.123). CONCLUSIONS: The response time was statistically similar for the temperatures of 54°C, 55°C, and 56°C; however, the data were less dispersed for the latter temperature.