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Published on: August 22, 2014
Regular exercise prevents oxidative stress in the brain of hyperphenylalaninemic rats
Priscila Nicolao Mazzola1, Melaine Terra, Andrea Pereira Rosa
1Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Insights
Regular exercise helps mitigate oxidative stress in hyperphenylalaninemia (HPA) by improving antioxidant defenses. Physical training may restore the antioxidant system in HPA, offering a potential therapeutic strategy.
Area of Science:
- Biochemistry
- Neuroscience
- Exercise Physiology
Background:
- Phenylketonuria (PKU) results from phenylalanine hydroxylase deficiency, causing phenylalanine accumulation and associated neurodevelopmental issues.
- Oxidative stress is implicated in the neurophysiopathology of PKU, contributing to symptoms like mental retardation and seizures.
- Regular exercise enhances the body's antioxidant system capacity, aiding in the detoxification of reactive species.
Purpose of the Study:
- To investigate the impact of regular aerobic exercise on oxidative stress markers in the brains of hyperphenylalaninemic (HPA) rats.
- To assess the potential of physical training as a strategy to counteract exercise-induced oxidative stress in HPA.
Main Methods:
- Hyperphenylalaninemia (HPA) was induced in rats using alpha-methylphenylalanine and phenylalanine.
- Animals were divided into sedentary and exercise groups, further subdivided into saline and HPA subgroups.
- Exercise groups underwent 2 weeks of daily aerobic exercise; brain and soleus muscle tissues were analyzed for oxidative stress markers (TBA-RS, SOD, CAT, GPx) and glycogen content.
Main Results:
- HPA induced increased thiobarbituric acid reactive substances (TBA-RS) and superoxide dismutase (SOD) activity, while decreasing catalase (CAT) and glutathione peroxidase (GPx) activities.
- Regular exercise normalized most HPA-induced oxidative stress markers, except for SOD activity, and increased soleus muscle glycogen content.
- Exercise did not alter parameters in saline-treated sedentary rats, indicating specific benefits for the HPA condition.
Conclusions:
- Regular exercise effectively counteracts HPA-induced oxidative stress in the brain, restoring antioxidant system balance.
- Physical training demonstrates potential as a therapeutic intervention to improve antioxidant capacity in hyperphenylalaninemia.
- Hyperphenylalaninemic rats exhibited enhanced responsiveness to the benefits of regular exercise, highlighting its protective role.
Abstract:
Phenylketonuria (PKU) is caused by deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine and its metabolites. Clinical features of PKU patients include mental retardation, microcephaly, and seizures. Oxidative stress has been found in these patients, and is possibly related to neurophysiopatology of PKU. Regular exercise can leads to adaptation of antioxidant system, improving its capacity to detoxification reactive species. The aim of this study was to verify the effects of regular exercise on oxidative stress parameters in the brain of hyperphenylalaninemic rats. Animals were divided into sedentary (Sed) and exercise (Exe) groups, and subdivided into saline (SAL) and hyperphenylalaninemia (HPA). HPA groups were induced HPA through administration of alpha-methylphenylalanine and phenylalanine for 17 days, while SAL groups (n = 16-20) received saline. Exe groups conducted 2-week aerobic exercise for 20 min/day. At 18th day, animals were killed and the brain was homogenized to determine thiobarbituric acid reactives substances (TBA-RS) content, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities. Soleus muscles were collected to determine glycogen content as a marker of oxidative adaptation. Exe groups showed enhanced glycogen content. HPA condition caused an increase in TBA-RS and SOD, and reduces CAT and GPx. Exercise was able to prevent all changes seen in the HPA group, reaching control values, except for SOD activity. No changes were found in the ExeSAL group compared to SedSAL. Hyperphenylalaninemic rats were more responsive to the benefits provided by regular exercise. Physical training may be an interesting strategy to restore the antioxidant system in HPA.
