Protocatechuic acid attenuates cerebral aneurysm formation and progression by inhibiting TNF-alpha/Nrf-2/NF-kB-mediated inflammatory mechanisms in experimental rats

Our current research aims to examine whether protocatechuic acid (PCA) can be used as a therapeutic agent for the development of cerebral aneurysm (CA) and to elucidate the mechanisms behind this. We assessed the effects of PCA at 50 and 100 mg/kg on the activation of signaling pathways for tissue necrosis factor (TNF)-α/nuclear factor (NF)-κB/nuclear factor erythroid 2 (Nrf-2) on progression and development in an elastase-induced CA model, accompanied by a high-salt diet to induce hypertension. The expression of inflammatory cytokines, chemokines, tumor necrosis factor-α, interleukins (IL)-8, IL-17, IL-6, IL-1β, and matrix metalloproteinase (MMP)-2 and MMP-9 was analyzed by ELISA, western blot, and reverse transcriptase quantative polymerase chain reaction. The expression levels of antioxidant enzymes and translocation of Nrf-2 were also determined. The group treated with PCA demonstrated a significant (P < 0.05) decrease in the aneurysmal size in rats compared to the CA-induced group. We found that PCA treatment suppressed the invasion of macrophage and activation of TNF-α/NF-κB/Nrf-2 signaling pathways. There was a significant decrease (P < 0.05) in pro-inflammatory cytokine and chemokine levels in a dose-dependent manner. We found that PCA treatment exerts protective effects by suppressing the development and progression of CA through the inhibition of inflammatory responses in macrophages via TNF-α/NF-κB/Nrf-2 signaling pathways, thus demonstrating that PCA can act as a treatment for CA.