This finding may demonstrate that based on the juxtaposition of astrocytes with brain blood vessels, astrocytes may be better positioned to respond to the anti-inflammatory effects of SFN. To our knowledge, this is the first evidence to suggest that dietary broccoli influences GFAP. In light of this, it would be interesting to further examine the effects of feeding a broccoli-supplemented diet to mice on changes in surface
expression of glial reactivity markers selleck compound library in primary culture. This has been tested to some extent with SFN, but to our knowledge, not with dietary broccoli. We also observed evidence of microglia or perivascular macrophage reactivity. Increased expression of the genetic marker for microglia/macrophage activation, CD11b, was expectedly increased in animals treated with LPS. Expression of CD11b was unaffected by diet, suggesting that neither microglia nor brain resident macrophages were responsive to the beneficial effects of a broccoli diet in our model. This was surprising, given that microglia and macrophages are robust producers of reactive oxygen and nitrogen species during inflammatory stimulation. However, these cells are also quite sensitive to LPS-induced inflammation, and the dose of LPS used STA-9090 may have overwhelmed the beneficial
effects of dietary broccoli. These data indicate that gliosis induced by a peripheral stimulus is aggravated by age and that dietary broccoli may reduce aging-associated glial reactivity. The fractalkine ligand (CX3CL1) and fractalkine receptor (CX3CR1) is an important regulatory system for tempering the microglial response after activation from endogenous and exogenous immune stimuli. Indeed, mice with a genetic deletion of CX3CR1 have an exaggerated
microglial for inflammatory response and increased duration of sickness behavior compared with wild-type mice. CX3CR1 knockout mice have a similar response to LPS treatment as to that observed in aged animals [28], [43] and [44]. In addition, it has been demonstrated that LPS decreases CX3CR1 at both the mRNA and protein level in microglia [28]. We observed an LPS-induced decrease in CX3CR1 expression in our model that was prevented in aged animals given LPS and fed broccoli diet. These data suggest that aged animals that consume dietary broccoli may have suppressed microglial activation compared with animals that do not consume broccoli in the diet and therefore may have improved long-term brain health, for example, improved neuron survival and increase in neurogenesis, when confronted with infectious disease due to potential suppression of microglial hyperactivity that has been described in aged mice [28] and [45].