Olanzapine modulation of hepatic oxidative stress and inflammation in socially isolated rats

Nevena Todorović, Nada Tomanović, Peter Gass, Dragana Filipović

Olanzapine, an atypical antipsychotic, is efficient in stress associated psychiatric diseases, but its effect on the liver, a primary organ for drug activation and detoxification, still remains unclear. The effect of olanzapine administration (7.5mg/kg/day), on rat hepatic glutathione (GSH)-dependent defense and proinflammatory cytokines following 6weeks of chronic social isolation (CSIS), which causes depressive- and anxiety-like behavior in adult male Wistar rats, was investigated. The subcellular distribution of nuclear factor-κB (NF-κB), cytosolic inducible nitric oxide synthase (iNOS) protein levels and hepatic histological alterations were also determined. Decreased GSH content and glutathione reductase activity associated with increased catalase and glutathione S-transferase activity following CSIS indicated hepatic oxidative stress. Moreover, CSIS caused NF-κB nuclear translocation and the concomitant increase in iNOS together with increase in interleukin-1beta and tumor necrosis factor alpha protein levels, but no effect on interleukin-6. Olanzapine treatment suppressed NF-κB activation and iNOS expression and caused modulation of GSH-dependent defense systems but failed to reverse CSIS-induced increase in hepatic proinflammatory cytokines. Portal inflammation, focal hepatocyte necrosis and an increased number of Kupffer cells in CSIS rats (vehicle- or olanzapine-treated) were found. Olanzapine-treated socially reared rats showed portal inflammation and focal hepatocyte necrosis. Data suggest that CSIS compromised GSH-dependent defense, triggered a proinflammatory response and histological alterations in rat liver. Olanzapine treatment partially reversed the alterations in hepatic GSH-dependent defense, but showed no anti-inflammatory effect suggesting that it may provide protective effect against hepatic CSIS-induced oxidative stress, but not against inflammation.