Frézier et al. 2025_Pain expression, cognition and gut microbiota composition in LOU vs. SD rats_Data raw
Description
To investigate a gut-brain axis involvement in pain management of musculoskeletal disease in the elderly, this study aimed to compare osteoarthritis (OA) pain expression, cognitive function and gut microbiota composition in two different elderly (11-15 months) rat strains. We hypothesized that pain expression (sensitization and CPM) will be different between LOU and SD elderly rat strains after OA induction using the MI-RAT© model. If this hypothesis of pain response was met, the exploration of the consequences on spinal NP, cognition and gut microbiota will be compared between the LOU and SD elderly OA rats. The first objective of this study was to investigate the temporal and comparative evolution of OA pain expression in elderly SD and LOU rat strains through an exhaustive pain phenotype platform. The second goal was to observe their cognitive function and composition of gut microbiota after OA induction. The validated MI-RAT© model was induced in Sprague-Dawley (SD; n = 12), as standard group, and in LOU/c/jall rats (n = 8), as healthy aging model. Response to OA pain was assessed longitudinally (60 days) through quantitative sensory testing (mechanical sensitization and endogenous inhibitory control functionality), spatial memory, and gut microbiota. At sacrifice, joint structural alterations and spinal neuropeptides concentration were quantified. After OA induction, higher mechanical hypersensitivity in LOU than in SD was counteracted by higher endogenous inhibitory control (p < 0.05). Expression of pro- and anti-nociceptive spinal neuropeptides, cognitive function and joint alterations were similar in both groups. Gut microbiota composition was different (p < 0.001) and different taxa were associated with each strain (e.g., Akkermansia spp. with LOU vs. Lactobacillus spp. with SD). This study suggests healthy aging to be associated with more efficient endogenous pain control and expression of specific intestinal bacteria. This research potentiates the role of the intestinal microbiota in aging and pain control.