The expression of an intraspecific aggressive reaction in the face of a stressor agent alters the immune response in rats

Abstract

The repercussion on the immune response of the expression of intraspecific aggressiveness in the face of a stressor agent was investigated in rats. Ninety-day-old animals were divided into three groups: the control group (only immunological measurements were performed), the foot-shock (FS) (animals individually receiving FS), and the intraspecific aggressive response (IAR) group (animals receiving FS and presenting IAR). For immunological measurements, blood samples were collected promptly at 7 and 15 days after FS or IAR. The FS reduced the total leukocyte amount presented. However, aggressiveness triggered not only reduction of the leukocytes, but also lymphocyte decrease and neutrophil increase. Moreover, an elevation in total leukocytes associated with an increase in the humoral immune response was also observed one week after IAR. In this study, the expression of intraspecific aggressiveness in the face of a stressor seemed to activate the immune system and to potentiate the antigen specific humoral response.Key words: intraspecific aggressiveness, leukocytes, humoral immune response. RESUMOA expressão de uma reação agressiva intra-específica diante de um estressor altera a resposta imune em ratos A repercussão sobre a resposta imune da expressão da agressividade intra-específica diante de um estressor foi investigada em ratos. Aos 90 dias de vida, os animais foram divididos em três grupos: grupo-controle (foram realizadas apenas mensurações imunológicas), choque nas patas (FS) (os animais receberam FS individualmente) e grupo resposta agressiva intra-específica (IAR) (os animais receberam FS e apresentaram IAR). Para as medições imunológicas, amostras de sangue foram coletadas imediatamente, 7 e 15 dias após FS ou IAR. O FS reduziu a quantidade total de leucócitos. Contudo, a agressividade foi acompanhada, além da redução do número de leucócitos, por diminuição de linfócitos e aumento de neutrófilos. Além disso, também foi observada elevação no número de leucócitos associada a aumento na resposta imune humoral uma semana após as IAR. Neste estudo, a expressão da agressividade intra-específica diante de um estressor parece ativar o sistema imune e potencializar a resposta humoral antígeno específica.Palavras-chave: agressividade intra-específica, leucócitos, resposta imune humoral.

Stress/Aggressiveness-Induced Immune Changes Are Altered in Adult Rats Submitted to Neonatal Malnutrition

“…Studies on interrelations between aggressive behavior and immune function in mammals are scarce, and those focused on the control of the interference of the stress factor are even rarer. Our data corroborate experimental evidence indicating immunological alterations in animals submitted to acute stress [2,3,24,25] . In fact, the HPA axis as well as other elements of stress responses are related to the expression of aggressive behavior [4,26] .…”

“…The aggressive response was defined as the presentation of at least one of the two following behaviors: (a) the animals maintained an erect posture, one facing the other, in a threatening attitude but without direct contact, or (b) they maintained evident physical contact (besides scratches, exhibition of the tooth and emission of characteristic vocalization) [3] .…”

“…Our recent studies have indicated that the expression of intraspecific aggressiveness seems to trigger the immune system and to raise antigen-specific humoral responses [3] . In the present study, the effect of aggressiveness-induced immune changes was assessed in adult rats submitted to neonatal malnutrition.…”

Hematological and immunological effects of stress of air traffic controllers in northeastern Brazil

“…(32) There are some studies (5) in animals and humans that demonstrate that stress reduces the total leukocyte count, thus corroborating our results.…”

The quest for indigenous aquafeed ingredients: a review

“…In the study by Mohamadi et al (2013), RBC indices, WBC and neutrophil levels significantly increased in fish fed 150 mg L À1 Eucalyptus spp. extract, which could be an adaptive response resulting in enhanced immune defence (Barreto-Medeiros et al 2005). Microbial content in samples of fish skin and gills was also quantified in terms of colony-forming units (CFU) seen in agar plates.…”