Eighteen-month-old Fischer 344 rats fed a spinach-enriched diet show improved delay classical eyeblink conditioning and reduced expression of tumor necrosis factor α (TNFα) and TNFβ in the cerebellum

Abstract

Diets high in antioxidant properties are known to reverse some deficits in neuronal and cognitive function that occur in aging animals. Antioxidants are also known to reduce levels of proinflammatory factors in the CNS. We report here that 6 weeks of a spinach-enriched diet ameliorates deficits in cerebellar-dependent delay classical eyeblink learning and reduces the proinflammatory cytokines tumor necrosis factor α (TNFα) and TNFβ in the cerebelli of eyeblink-trained animals. Eighteen-month-old Fischer 344 rats were given spinach-enriched lab chow or regular lab chow for 6 weeks. The rats were then given 6 d of 30 trials per day training using a 3 kHz tone conditioned stimulus and airpuff unconditioned stimulus. Rats were killed 3 weeks after eyeblink training. Cytokine expression was measured using RNase protection assay analysis in the eyeblink-trained animals and in a group of young control animals given regular lab chow diet. Old animals on the spinach-enriched lab chow diet learned delay eyeblink conditioning significantly faster than old animals on the regular diet. Cerebelli from older animals on the spinach-enriched diet had significantly less TNFα and TNFβ than cerebelli from older animals on the control diet.