Mejoría de la inmunidad y la esperanza de vida en ratones maduros, genéticamente deficientes en la síntesis de catecolaminas, tras convivir con controles durante dos meses / Improved immunity and mean lifespan in mature mice genetically deficient in catecholamine synthesis after living with wild type for two months

Introducción: Los ratones hemicigotos en la tirosina hidroxilasa (TH-HZ), enzima limitante en la síntesis de catecolaminas, muestran una inmunosenescencia prematura, que en hembras se asocia con menor esperanza de vida que los correspondientes controles (WT). La convivencia de los TH-HZ con WT permite, en la edad adulta, una normalización de la función inmunitaria tanto en machos como en hembras. Objetivo: Comprobar si la convivencia durante dos meses de machos maduros TH-HZ con WT produce una mejoría de la función inmunitaria de los primeros y si esto repercute en una mayor esperanza de vida media. Material y métodos: Ratones macho ICR-CD1 maduros (13 ± 1 meses) TH-HZ convivieron con WT (proporción 2:4 por jaula) dos meses. Al inicio, al mes y a los dos meses de convivencia se extrajeron los leucocitos peritoneales de los animales y se valoró la capacidad fagocítica de macrófagos, la quimiotaxis de macrófagos y linfocitos, la actividad antitumoral natural killer (NK) y la capacidad linfoproliferativa en respuesta a los mitógenos concanavalina A y lipopolisacarido. Los animales se mantuvieron en esas condiciones hasta su muerte natural. Resultados: Los TH-HZ parten, en general, con peor función inmunitaria y menor longevidad que los WT, observando una mejoría de esta tras la convivencia, alcanzándose valores similares a los controles. En la actividad NK esa mejoría se observó al mes de convivencia. Conclusión: La convivencia de los ratones macho TH-HZ con los WT durante dos meses, en la edad madura, permite mejorar la respuesta inmunitaria y la longevidad de esos animales genéticamente modificados. (AU)

Introduction: Mice hemizygous in tyrosine hydroxylase (TH-HZ), the limiting enzyme in catecholamine synthesis, show premature immunosenescence, which in females is associated with a shorter lifespan than the corresponding controls (WT). The coexistence of TH-Hz with WT improves the immune function in both males and females in adulthood. Objective: To test whether cohabitation for two months of mature male TH-HZ with WT improves the immune function of the former and whether this impacts the lifespan. Material and methods: Mature male ICR-CD1 mice (13 ± 1 months) TH-HZ coexisted with WT (2:4 ratio in each cage) for two months. Peritoneal leukocytes were extracted from all animals at baseline, one month, and two months after cohabitation, and macrophage phagocytic capacity, macrophage and lymphocyte chemotaxis, natural killer (NK) antitumor activity, and lymphoproliferative capacity in response to the mitogens concanavalin A and lipopolysaccharide (LPS) were assessed. The animals were maintained under these conditions until their natural death. Results: The TH-HZ, which start, in general, with lower values than the WT in the immune functions studied, improved them after two months of cohabitation, becoming similar to those of the controls. This improvement was already observed in NK activity after one month of cohabitation. The TH-HZ presented lower mean longevity than WT, but when they cohabited with WT, it was similar to the latter. Conclusion: The coexistence of TH-HZ male mice with WT mice for two months at mature age improves these genetically modified animals’ immune response and longevity. (AU)

[Improved immunity and mean lifespan in mature mice genetically deficient in catecholamine synthesis after living with wild type for two months]. / Mejoría de la inmunidad y la esperanza de vida en ratones maduros, genéticamente deficientes en la síntesis de catecolaminas, tras convivir con controles durante dos meses.

INTRODUCTION: Mice hemizygous in tyrosine hydroxylase (TH-HZ), the limiting enzyme in catecholamine synthesis, show premature immunosenescence, which in females is associated with a shorter lifespan than the corresponding controls (WT). The coexistence of TH-Hz with WT improves the immune function in both males and females in adulthood. OBJECTIVE: To test whether cohabitation for two months of mature male TH-HZ with WT improves the immune function of the former and whether this impacts the lifespan. MATERIAL AND METHODS: Mature male ICR-CD1 mice (13 ± 1 months) TH-HZ coexisted with WT (2:4 ratio in each cage) for two months. Peritoneal leukocytes were extracted from all animals at baseline, one month, and two months after cohabitation, and macrophage phagocytic capacity, macrophage and lymphocyte chemotaxis, natural killer (NK) antitumor activity, and lymphoproliferative capacity in response to the mitogens concanavalin A and lipopolysaccharide (LPS) were assessed. The animals were maintained under these conditions until their natural death. RESULTS: The TH-HZ, which start, in general, with lower values than the WT in the immune functions studied, improved them after two months of cohabitation, becoming similar to those of the controls. This improvement was already observed in NK activity after one month of cohabitation. The TH-HZ presented lower mean longevity than WT, but when they cohabited with WT, it was similar to the latter. CONCLUSION: The coexistence of TH-HZ male mice with WT mice for two months at mature age improves these genetically modified animals' immune response and longevity.

[Premature immunosenescence in catecholamines syntesis deficient mice. Effect of social environment]. / Inmunosenescencia prematura en ratones con una deficiencia en la síntesis de catecolaminas. Efecto del ambiente social.

INTRODUCTION: Healthy state depends on the appropriate function of the homeostatic systems (nervous, endocrine and immune systems) and the correct communication between them. The functional and redox state of the immune system is an excellent marker of health, and animals with premature immunosenescence show a shorter lifespan. Since catecholamines modulate the function of immune cells, the alteration in their synthesis could provoke immunosenescence. The social environment could be a strategy for modulating this immunosenescence. AIM: To determine if an haploinsufficiency of tyrosine hydroxylase (TH), the limiting enzyme of synthesis of catecholamines, may produce a premature immunosenescence and if this immunosenescence could be modulated by the social environment. MATERIALS AND METHODS: Adult (9±1 months) male ICR-CD1 mice with deletion of a single allele (hemi-zygotic: HZ) of the tyrosine hydroxylase enzyme (TH-HZ) and wild-type (WT) mice were used. Animals were housed in four subgroups: WT>50% (in the cage, the proportion of WT mice was higher than 50% in relation to TH-HZ), WT<50%, TH-HZ<50% and TH-HZ>50%. Peritoneal leukocytes were collected and phagocytosis, chemotaxis and proliferation of lymphocytes in the presence of lipopolysaccharide were analyzed. Glutathione reductase and glutathione peroxidase activities as well as oxidized/reduced glutathione ratio were studied. RESULTS: TH-HZ>50% mice showed a deteriorated function and redox state in leukocytes respect to WT>50% and similar to old mice. However, TH-HZ<50% animals had similar values to those found in WT<50% mice. CONCLUSION: The haploinsufficiency of TH generates premature immunosenescence, which appears to be compensated by living together with an appropriate number of WT animals.