Oxytocin administration improves memory, anxiety and some oxidative stress parameters in a methionine-induced rat model of schizophrenia

Abstract

Lately there is an increased interest in understanding the possible relevance of oxytocin administration in the schizophrenic pathology. Also, currently in the literature there are models of schizophrenia, such as the one based on methionine administration, capable of replicating both positive and negative specific symptoms of schizophrenia, as well as the cognitive deficits from this disorder, which are believed to affect up to 75% of patients diagnosed with schizophrenia. In this context, in the present paper we were interested in preliminary revealing the effects of intraperitoneally oxytocin administration for 9 days, in a new approach, in a rat model of schizophrenia generated by administration of methionine for 2 weeks, on the memory and anxiety deficits induced by methionine administration (as studied in Y maze and elevated plus maze tasks), as well as on the oxidative stress markers (two antioxidant enzymes: superoxide dismutase-SOD and glutathione peroxidase-GPX, and the lipid peroxidation biomarker, malondialdehyde-MDA) from the temporal lobe. Our results showed some ameliorative effects of oxytocin administration on the immediate spatial memory (increased spontaneous alternation in Y maze) and anxiety-induced deficits (oxytocin increased the time spent in the open arms of the elevated plus maze) generated by the methionine-induced rat model of schizophrenia. Even more, oxytocin administration exerted some antioxidant effects in this model, as demonstrated by increased specific activity of GPX and reduced levels of MDA from the temporal lobe in the methionine + oxytocin group, as compared to the methionine group of rats. However, no significant modifications in SOD specific activity were found. This could have further relevance for the mechanistic behind the administration of oxytocin in the schizophrenia pathophysiology.