Ccn1 Mediates Pyroptosis and Purine Metabolism Pattern Shifts in a High-Uric Acid Microenvironment After Spinal Cord Injury

Spinal cord injury (SCI) often results in permanent functional loss due to the complexity of the post-SCI microenvironment, but the composition and functional dynamics of the post-SCI microenvironment remain poorly understood. We applied spatial metabolomics to detect metabolites within the spinal cord of SCI rats, revealing the existence of a high-uric acid (hUA) microenvironment. Subsequently, we utilized Bulk-RNA sequencing and single-cell RNA sequencing (scRNA-seq) analysis, identified elevated expression of Cellular communication network factor 1 (Ccn1) and alterations in purine metabolic patterns. To investigate the role of Ccn1 within this hUA microenvironment, PC12 cell line and Sprague–Dawley (SD) rats were used. In vitro , 4 groups were designed: Control ( n  = 6), UA (PC12 cells treated with 200 μM UA for 24 h) ( n  = 6), siCcn1 ( Ccn1 knockdown using small interfering RNA) ( n  = 6), and siCcn1  + UA ( n  = 6). In vivo groups: SCI (spinal cord injury only) ( n  = 6), hUA (induced hUA microenvironment by gavage with oxonic acid potassium salt 750 mg/kg and and ethambutol 250 mg/kg) ( n  = 6), AAV ( Ccn1 knockdown via adeno-associated virus) ( n  = 6), and AAV  + hUA ( n  = 6). Results showed that UA significantly reduced cellular aerobic respiration levels (Control vs UA: 62.87 ± 16.76 vs 17.09 ± 4.91 pmol/min, P  < 0.01) and induced pyroptosis, Ccn1 knockdown significantly improved aerobic respiration ( siCcn1  + UA vs UA: 46.45 ± 12.54 vs 17.09 ± 4.91 pmol/min, P  < 0.05) and reduced the level of pyroptosis. Total cellular ATP levels, the NAD⁺/NADH ratio, and proliferation capacity were also assessed. In vivo , Ccn1 knockdown significantly increased the Basso, Beattie, and Bresnahan (BBB) locomotor scores of animals on the 7 days post-injury ( AAV  + hUA vs hUA: 3.33 ± 0.52 vs 2.00 ± 0.63, P  < 0.05) and reduced neuronal pyroptosis. The hUA microenvironment upregulated Ccn1 expression, suppressed aerobic respiration, induced pyroptosis, and disrupted purine metabolism, Ccn1 knockdown reversed these biological processes, suggesting its potential as a therapeutic target for SCI.