Beneficial effects of hydrotherapy on immunity and longevity in a mouse model of social isolation

Abstract

Introduction: Hydration and Hydrotherapy is a new type of environmental enrichment strategy, reverting the age-related decline of the homeostatic systems (nervous, endocrine and immune systems), enhancing the neuroendocrine-immune communication and, consequently, improving health and life span. In social species (humans, rodents), loneliness and social isolation are psychological stressors which impair the neuroendocrine-immune communication, increasing morbidity and mortality. Since aging especially affects homeostatic systems and older adults are more vulnerable to feeling lonely or socially isolated, suffering these stressors may aggravate health state in the later stages of life. Objective: The aim of this work was to study the effects of hydration-hydrotherapy on immunity and life span in socially isolated old mice. Method: ICR-CD1 old female mice were maintained in group (n=8) or isolated (n=10) during one month. Then, a group of isolated mice (n=5) was submitted to a 4-weeks hydrotherapy treatment. Peritoneal leukocytes were obtained and macrophages and lymphocytes chemotaxis, and lymphoproliferation in absence (basal) or presence of the mitogens Lipopolyssaccharide and Concanavalin A were analyzed. Mortality was also monitored. Results: Hydration and Hydrotherapy improves lymphocytes chemotaxis and lymphoproliferative response to mitogens (functions reduced with aging), decreases basal lymphoproliferation (which increases with age) and increases life span in socially isolated mice. Conclusions: Hydration-Hydrotherapy seems to be an effective strategy to reverse the immune decline induced by social isolation in elderly as well as to increase longevity.