Preventive effects of multisensory rehabilitation on development of cognitive dysfunction following systemic inflammation in aged rats

Systemic inflammation can trigger transient or longer-lasting cognitive impairments, particularly in elderly patients. However, its pathogenesis has not been sufficiently clarified. In this study, we explored the potential effects of multisensory rehabilitation on cognitive dysfunction following systemic inflammation using an animal model. Aged male Wister rats were randomly injected intraperitoneally with either saline (control) or lipopolysaccharide (LPS; 5 mg/kg). After injection, both groups of rats were randomly assigned to either of two housing conditions (n = 8 in each condition): a standard cage environment (SC group) or a multisensory early rehabilitation environment (ER group). Cognitive function was examined after 7 days in the assigned environmental condition using a novel object recognition test. In the SC group, the LPS-treated rats showed impaired cognitive function compared with the control animals. These memory deficits were positively correlated with the levels of both tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta in the hippocampus. On the other hand, in the LPS-treated ER group, neither cognitive impairment nor an increase in hippocampal levels of both TNF-alpha and IL-1 beta was found. These results imply that early rehabilitation (ER) intervention may be effective in preventing cognitive dysfunction following systemic inflammation via its anti-neuroinflammatory effects.