The Art & Science of Learning Design

Cognitive dysfunction is highly prevalent in older adults and severely impairs daily activities and quality of life. Rehabilitation training alleviates aging-related cognitive dysfunction (ARCD); however, the mechanisms underlying differential effects of different training regimens remain poorly understood. Motor training relieves TMAO-triggered neuroinflammation, while cognitive training (CT) improves ARCD via suppression of chronic inflammatory signaling. Cognitive-motor dual-task training (CMDT) yields more obvious cognitive protection than single-mode training, yet the molecular mechanisms accounting for its enhanced protective capacity have not been fully clarified. Thirty 18-month-old male SD rats were subjected to D-galactose injection to establish the ARCD model and randomly divided into five groups (n = 6 per group). Partial model rats received exogenous TMAO administration to verify its neurotoxicity. Animals were treated with CT or CMDT intervention separately. Novel object recognition (NOR) and Morris water maze (MWM) tests were adopted to assess cognitive function; UHPLC-MS/MS, Western blotting and Co-IP were used to detect peripheral and hippocampal TMAO as well as inflammatory protein expression. HT22 cell models were constructed for in vitro validation, with three independent biological replicates set for all molecular measurements. In vivo results showed that CT significantly alleviated cognitive deficits and downregulated hippocampal TXNIP and NLRP3 expression (P < 0.05), without changing circulating or hippocampal TMAO levels (P > 0.05). In contrast, CMDT generated more prominent cognitive improvements and simultaneously reduced TMAO accumulation together with TXNIP overexpression (P < 0.05). In vitro experiments showed that TMAO aggravated D-galactose-induced neuronal senescence and inflammatory activation, which was associated with up-regulation of the TXNIP-NLRP3 inflammatory cascade, and inhibiting TXNIP could reverse such pathological injury. Co-IP assays further showed that TMAO promoted the binding of NLRP3 to ASC, while the caspase-8-ASC binding showed no significant differences across all groups. CMDT exhibits relatively better therapeutic effects against ARCD compared with CT. The present observations reveal that CMDT-related cognitive improvement occurs alongside reduced TMAO accumulation and suppressed TXNIP-NLRP3 inflammatory pathway activation. Combined with our prior MT experimental data, the stronger intervention capacity of CMDT may be related to regulatory effects originating from its cognitive and motor components. This study provides experimental evidence supporting CMDT as a potential rehabilitation strategy for ARCD.