EC-SOD gene therapy reduces paracetamol-induced liver damage in mice

Background: Paracetamol overdose causes acute liver damage which leads to severe centrilobular hepatic necrosis. The hepatotoxic effect is caused by reactive metabolites and oxidative stress. Since extracellular Superoxide dismutase (EC-SOD) protects tissues against the harmful effects of Superoxide anion, the hypothesis that systemic adenovirus-mediated EC-SOD gene transfer could reduce liver damage was tested. Methods: Mice were given paracetamol (600 mg/kg) enterally 2 days after adenovirus-mediated gene transfer of EC-SOD (2 ×10⁹ pfu). Five days after gene transfer, plasma and tissue samples were collected for clinical chemistry analyses and tissue pathology evaluation. Results: EC-SOD was expressed in a dose-dependent manner with the highest enzyme activity occurring 3 days after the gene transfer. Clinical chemistry and tissue pathology analyses showed that adenoviral EC-SOD gene transfer significantly attenuated release of liver enzymes and inhibited necrosis and apoptosis caused by paracetamol overdose. Conclusion: The results indicate the involvement of Superoxide anion in paracetamol-mediated liver damage and suggest a possible protective role for EC-SOD gene transfer in paracetamol-induced liver damage.