title: Melatonin fails to modulate immune parameters influenced by calorie restriction in aging Fischer 344 rats.
abstract: The aim of this study was to determine if long-term treatment with melatonin (MEL), a purported anti-aging agent, was as effective as calorie restriction (CR) in modulating immune parameters in aging Fischer 344 male rats. Splenic lymphocytes were isolated from 17-month-old rats that, beginning at 6 weeks of age, were treated with MEL (4 or 16 microg/ml in drinking water) and from 17-month-old rats fed ad libitum (AL) or rats fed a CR diet (55% of AL intake). The number of splenic T cell populations and T cell subsets was measured by flow cytometry, the proliferative response of splenocytes to Concanavalin A (Con A) and lipopolysaccharide (LPS) was measured by [(3)H]thymidine incorporation, and the induction of cytokine production (IL-2 and IFN-gamma) was measured by ELISA assay. In addition, the level of the natural killer (NK) cell activity was assessed by fluorimetric assay. CR rats had a higher number of lymphocytes expressing the naïve T cell marker (CD3 OX22) than AL rats (P < 0.05). CR rats also showed greater induction of proliferative response, IL-2 and IFN-gamma levels following Con A simulation, and NK cell activity than AL rats (P < 0.05). MEL-treated rats did not differ from AL rats in any of these parameters or in any other measurement. These results indicate that MEL treatment is unable to modulate immune function in a manner comparable with that of CR.
authors.affiliation: Department of Physiology, University of Texas Health Science Center, San Antonio, Texas 78229, USA. Pahlavani@uthscsa.edu
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Pahlavani
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Vargas
authors.forename: Ted R
authors.initials: TR
authors.lastname: Evans
authors.forename: Jian-hua
authors.initials: JH
authors.lastname: Shu
authors.forename: James F
authors.initials: JF
authors.lastname: Nelson
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000375:Aging / Q000276:immunology* / Q000502:physiology; D000818:Animals; D004032:Diet; D002149:Energy Intake; D007109:Immunity / Q000187:drug effects* / Q000502:physiology; D008550:Melatonin / Q000276:immunology / Q000494:pharmacology*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D000276:Adjuvants, Immunologic; D008550:Melatonin