A Transgenic Dwarf Rat Strain as a Tool for the Study of Immunosenescence in Aging Rats and the Effect of Calorie Restriction

Immunosenescence or dysregulation of the immune system may accelerate the aging process and shorten the lifespan in animals. Calorie restriction, a well-known nutritional intervention for longevity in laboratory animals, retards immunosenescence and modulates the immunosystem. These effects of CR could contribute partly to extending the lifespan. A transgenic (Tg) dwarf rat strain, in which the growth hormone (GH) axis is selectively suppressed, lived longer and exhibited several phenotypes similar to those in CR rats, suggesting an important role for the GH axis in the effect of CR. Here, we describe the longevity, pathology, thymic and splenic lymphocyte subpopulations and response to endotoxin in Tg rats in comparison with CR rats. The findings support the importance of the GH axis in the effect of CR on the immune system and, in particular, longevity. The Tg rats could be a useful tool to better understand the molecular mechanisms underlying the antiaging effect of CR.