MMP9 and post-traumatic stress disorder: Elevated MMP-2 (median: 21.66 ng/mL, IQR: 16.90–23.80) and MMP-9 (median: 418.70 ng/mL, IQR: 341.08–558.19) levels in the Past PTSD (≤5 y) group compared to the controls (MMP-2: median: 1.75 ng/mL, IQR: 1.37–2.11; MMP-9: median: 48.99 ng/mL, IQR: 39.77–58.23, p < 0.001, Section 2.1, Table 1) may compromise PNN integrity, impairing GABA synthesis and release.