Proline Alters Antioxidant Enzyme Defenses and Lipoperoxidation in the Erythrocytes and Plasma of Rats: In Vitro and In Vivo Studies Roberto Roecker & Gustavo M. Junges & Daniela Delwing de Lima & José Geraldo Pereira da Cruz & Angela T. S. Wyse & Débora Delwing Dal Magro Received: 11 October 2011 /Accepted: 14 November 2011 /Published online: 2 December 2011 # Springer Science+Business Media, LLC 2011 Abstract In the present study, we investigated, in vivo (acute and chronic) and in vitro, the effects of proline on the activities of antioxidant enzymes such as catalase (CAT), glutathione peroxidase and superoxide dismutase (SOD) in erythrocytes and also investigated the effect on thiobarbi- turic acid-reactive substances (TBARS) in the plasma of rats. For the experiments, the number of animals per group ranged from eight to ten. For acute administration, 29-day- old rats received one subcutaneous injection of proline (18.2 μmol/g body weight) or an equivalent volume of 0.9% saline solution (control) and were killed 1 h later. For chronic treatment, buffered proline was injected subcutane- ously into rats twice a day at 10 h intervals from the 6th to the 28th day of age. Rats were killed 12 h after the last injection. For in vitro studies, proline (30.0 μM to 1.0 mM) was added to the incubation medium. Results showed that acute administration of proline reduced CAT and increased SOD activities, while chronic treatment increased the activities of CAT and SOD in erythrocytes and TBARS in the plasma of rats. Furthermore, in vitro studies showed that proline increased TBARS in the plasma (0.5 and 1.0 mM) and CAT activity (1.0 mM) in the erythrocytes of rats. The influence of the antioxidants (α-tocopherol plus ascorbic acid) on the effects elicited by proline was also studied. Treatment with antioxidants for 1 week or from the 6th to the 28th day of age prevented the alterations caused by acute and chronic, respectively, proline administration on the oxidative parameters evaluated. Data indicate that proline alters antioxidant defenses and induces lipid peroxidation in the blood of rats. Keywords Hyperprolinemia . Antioxidant enzymes . TBARS . Erythrocytes . α-Tocopherol . Ascorbic acid Introduction Several conditions and disorders are caused by enzyme defects in the metabolism of amino acids. Type II hyper- prolinemia (HPII) is a rare inherited autosomal recessive disorder of amino acid metabolism characterized by the hepatic deficiency of Δ-1-pyrroline-5-carboxylic acid dehydrogenase activity, which leads to the tissue accu- mulation of proline [1]. Affected patients present neuro- logical manifestations including seizures and mental retardation. While many hyperprolinemic individuals remain asymptomatic, high concentrations of proline and neurological symptoms have been demonstrated in patients with this disease [1]. J. G. Pereira da Cruz : D. D. Dal Magro (*) Departamento de Ciências Naturais, CCEN, Universidade Regional de Blumenau, Rua Antônio da Veiga, 140, CEP 89012-900 Blumenau, SC, Brazil e-mail: deboradelwing@furb.br D. D. de Lima Departamento de Medicina, Universidade da Região de Joinville–UNIVILLE, Campus Universitário, Bairro Bom Retiro, CEP 89201-972 Joinville, SC, Brazil R. Roecker : G. M. Junges Departamento de Medicina, Centro de Ciências da Saúde, Universidade Regional de Blumenau, Rua Antônio da Veiga, 140, CEP 89012-900 Blumenau, SC, Brazil A. T. S. Wyse Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600-Anexo, Porto Alegre, RS, Brazil Biol Trace Elem Res (2012) 147:172–179 DOI 10.1007/s12011-011-9276-6