Caloric restriction increases free radicals and inducible nitric oxide synthase expression in mice infected with Salmonella Typhimurium.
It is well known that CR (caloric restriction) reduces oxidative damage to proteins, lipids and DNA, although the underlying mechanism is unclear. However, information concerning the effect of CR on the host response to infection is sparse. In this study, 6-month-old mice that were fed AL (ad libitum) or with a CR diet were infected with Salmonella serovar Typhimurium. EPR (electron paramagnetic resonance; also known as ESR (electron spin resonance)) was used to identify FRs (free radicals). These results were subsequently correlated with SOD (superoxide dismutase) catalytic activity, iNOS [inducible NOS (nitric oxide synthase) or NOSII] expression and NO (nitric oxide) content. EPR analysis of liver samples demonstrated that there was a higher quantity of FRs and iron-nitrosyl complex in infected mice provided with a CR diet as compared with those on an AL diet, indicating that CR was beneficial by increasing the host response to Salmonella Typhimurium. Furthermore, in infected mice on the CR diet, NOSII expression was higher, NO content was greater and spleen colonization was lower, compared with mice on the AL diet. No changes in SOD activity were detected, indicating that the NO produced participated more in the formation of iron-nitrosyl complexes than peroxynitrite. These results suggest that CR exerts a protective effect against Salmonella Typhimurium infection by increasing NO production.
Trujillo-Ferrara
José
J
Sección de Estudios de Posgrado e Investigación y Departamento de Bioquímica de la Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, D.F. 11340, Mexico.
Campos-Rodríguez
Rafael
R
Lara-Padilla
Eleazar
E
Ramírez-Rosales
Daniel
D
Correa Basurto
José
J
Miliar Garcia
Angel
A
Reyna Garfias
Humberto
H
Zamorano Ulloa
Rafael
R
Rosales-Hernández
Martha C
MC
D000818:Animals; D031204:Caloric Restriction; D005609:Free Radicals / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D012480:Salmonella Infections / Q000201:enzymology* / Q000378:metabolism; D012486:Salmonella typhimurium; D013482:Superoxide Dismutase / Q000378:metabolism
D005609:Free Radicals; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D013482:Superoxide Dismutase