Diabetic encephalopathy-related depression: experimental evidence that insulin and clonazepam restore antioxidant status in rat brain.

Bioestatistica, Nucleo de Disciplinas Basicas da Saude, Instituto Metodista IPA, Porto Alegre, Rio Grande do Sul, BrazilThere is increasing evidence suggesting that oxidative stress plays an important role in the development of many chronic and degenerativeconditions such as diabetic encephalopathy and depression. Considering that diabetic rats and mice present higher depressive-like behaviourwhen submitted to the forced swimming test and that treatment with insulin and/or clonazepam is able to reverse the behavioural changes ofthe diabetic rats, the present work investigated the antioxidant status, specifically total antioxidant reactivity and antioxidant potential of in-sulin and clonazepam, as well as the effect of this drugs upon protein oxidative damage and reactive species formation in cortex, hippocam-pus and striatum from diabetic rats submitted to forced swimming test. It was verified that longer immobility time in diabetic rats and insulinplus clonazepam treatment reversed this depressive-like behaviour. Moreover, data obtained in this study allowed to demonstrate throughdifferent parameters such as protein carbonyl content, 2′7′-dichlorofluorescein oxidation, catalase, superoxide dismutase, glutathione perox-idase assay, total radical-trapping antioxidant potential and total antioxidant reactivity that there is oxidative stress in cortex, hippocampusand striatum from diabetic rats under depressive-like behaviour and highlight the insulin and/or clonazepam effect in these different brainareas, restoring antioxidant status and protein damage. Copyright © 2014 John Wiley & Sons, Ltd.key words—diabetes; depression; forced swimming test; GABA agonist; diabetic encephalopathy