L-carnitine protects against oxidative damage and neuroinflammation in cerebral cortex of rats submitted to chronic chemically-induced model of hyperphenylalaninemia.

Phenylketonuria is a genetic disorder characterized by high phenylalanine levels, the main toxic metabolite of the disease. Hyperphenylalaninemia can cause neurological impairment. In order to avoid this symptomatology, patients typically follow a phenylalanine-free diet supplemented with a synthetic formula that provides essential amino acids, including L-carnitine. This work aims to evaluate the potential neuroprotective effects of L-carnitine treatment in the cerebral cortex of rats submitted to a chronic chemically-induced model of Hyperphenylalaninemia, evaluating brain oxidative damage and neuroinflammation. We confirm the effectiveness of the animal model, through the increase of phenylalanine and L-carnitine in blood and cerebral cortex. L-carnitine treatment was effective in significantly decreasing the generation of reactive species and attenuating the superoxide dismutase (SOD) activity. Significant negative correlations between L-carnitine and superoxide dismutase as well as L-carnitine and reactive species generation were also found, reinforcing the involvement of oxidative stress and the effect of L-carnitine. Besides, L-carnitine attenuated the decrease in IL-4 levels, demonstrating both anti-inflammatory properties and a neuroprotective effect, through the decrease in the overexpression of the glial fibrillary acidic protein (GFAP) present in the cerebral cortex of rats with Hyperphenylalaninemia. Our results highlight the neuroprotective role of L-carnitine in the treatment of Phenylketonuria, mainly against neuroinflammation and the oxidative process, contributing to better clarify the pathophysiology of the disease.