Trans fat supplementation increases UV-radiation-induced oxidative damage on skin of mice.

We evaluated the influence of fish oil (FO, rich in n-3 FA), soybean oil (SO, rich in n-6 FA) and hydrogenated vegetable fat (HVF, rich in trans FA) on the oxidative status and viability of skin cells of mice exposed to ultraviolet radiation (UVR). Mice were supplemented with FO, SO or HVF for three months and exposed to UVR (2.72 mJ/cm(2)) for 2 days. One day after the last UVR session, the FO group showed higher levels of n-3 fatty acids (FA), while the HVF showed higher incorporation of trans FA (TFA) in dorsal skin. UVR increased lipid peroxidation and protein carbonyl levels of the HVF and to a lesser extent of the control and SO groups. Although all irradiated groups showed increased skin thickness, this increase was slighter in FO mice. UVR exposure reduced skin cell viability of the control, SO and HVF groups, while FO prevented this. Catalase activity was reduced independently of the supplementation and SOD level was increased in C and FO groups after UVR exposure; FO prevented the UVR-induced increase in glutathione levels, which was observed in skin of the control, SO and HVF mice. Our results showed the beneficial effects of FO supplementation, as well as the harmful effects of trans FA, whose intensity can increase vulnerability to skin diseases.

Influence of lifelong dietary fats on the brain fatty acids and amphetamine-induced behavioral responses in adult rat.

The influence of dietary fatty acids (FA) on mania-like behavior and brain oxidative damage were evaluated in rats. First generation of rats born and maintained under supplementation with soybean-oil (SO), fish-oil (FO) or hydrogenated-vegetable-fat (HVF), which are rich in n-6, n-3 and trans (TFA) FA, respectively, until adulthood, were exposed to an amphetamine (AMPH)-induced mania animal model to behavioral and biochemical evaluations. While AMPH caused hyperlocomotion in HVF and, to a less extent, in SO- and FO-groups, a better memory performance was observed in FO group. Among vehicle-groups, HVF increased reactive species (RS) generation and protein-carbonyl (PC) levels in cortex; FO reduced RS generation in hippocampus and decreased PC levels in hippocampus and striatum. Among AMPH-treated animals, HVF exacerbated RS generation in all evaluated brain areas and increased PC levels in cortex and striatum; FO reduced RS generation in hippocampus and decreased PC levels in hippocampus and striatum. FO was related to higher percentage of polyunsaturated fatty acids (PUFA) and docosahexaenoic acid (DHA) in cortex and striatum, while HVF was associated to higher incorporation of TFA in cortex, hippocampus and striatum, besides increased n-6/n-3 FA ratio in striatum. While a continuous exposure to TFA may intensify oxidative events in brain, a prolonged FO consumption may prevent mania-like-behavior; enhance memory besides decreasing brain oxidative markers. A substantial inclusion of processed foods, instead of foods rich in omega-3, in the long term is able to influence the functionality of brain structures related to behavioral disturbances and weaker neuroprotection, whose impact should be considered by food safety authorities and psychiatry experts.

Could dietary trans fatty acids induce movement disorders? Effects of exercise and its influence on Na⁺K⁺-ATPase and catalase activity in rat striatum.

The influence of trans fatty acids (FA) on development of orofacial dyskinesia (OD) and locomotor activity was evaluated. Rats were fed with diets enriched with 20% soybean oil (SO; n-6 FA), lard (L; saturated FA) or hydrogenated vegetable fat (HVF; trans FA) for 60 weeks. In the last 12 weeks each group was subdivided into sedentary and exercised (swimming). Brains of HVF and L-fed rats incorporated 0.33% and 0.20% of trans FA, respectively, while SO-fed group showed no incorporation of trans FA. HVF increased OD, while exercise exacerbated this in L and HVF-fed rats. HVF and L reduced locomotor activity, and exercise did not modify. Striatal catalase activity was reduced by L and HVF, but exercise increased its activity in the HVF-fed group. Na(+)K(+)-ATPase activity was not modified by dietary FA, however it was increased by exercise in striatum of SO and L-fed rats. We hypothesized that movement disorders elicited by HVF and less by L could be related to increased dopamine levels in striatum, which have been related to chronic trans FA intake. Exercise increased OD possibly by increase of brain dopamine levels, which generates pro-oxidant metabolites. Thus, a long-term intake of trans FA caused a small but significant brain incorporation of trans FA, which favored development of movement disorders. Exercise worsened behavioral outcomes of HVF and L-fed rats and increased Na(+)K(+)-ATPase activity of L and SO-fed rats, indicating its benefits. HVF blunted beneficial effects of exercise, indicating a critical role of trans FA in brain neurochemistry.

Exercise affects memory acquisition, anxiety-like symptoms and activity of membrane-bound enzyme in brain of rats fed with different dietary fats: impairments of trans fat.

Here we evaluated the influence of physical exercise on behavior parameters and enzymatic status of rats supplemented with different dietary fatty acids (FA). Male Wistar rats fed diets enriched with soybean oil (SO), lard (L), or hydrogenated vegetable fat (HVF) for 48 weeks were submitted to swimming (30 min/d, five times per week) for 90 days. Dietary FA per se did not cause anxiety-like symptoms in the animals, but after physical exercise, SO group showed a better behavioral performance than L and the HVF groups in elevated plus maze (EPM). In Barnes maze, HVF group showed impaired memory acquisition as compared to L group, and exercise reversed this effect. SO-fed rats showed an improvement in memory acquisition after 1 day of training, whereas lard caused an improvement of memory only from day 4. HVF-fed rats showed no improvement of memory acquisition, but this effect was reversed by exercise in all training days. A lower activity of the Na(+)K(+)-ATPase in brain cortex of rats fed lard and HVF was observed, and this effect was maintained after exercise. Similarly, the HVF diet was related to lower activity of hippocampal Na(+)K(+)-ATPase, and exercise reduced activity of this enzyme in the SO and L groups. Our findings show influences of dietary FA on memory acquisition, whereas regular exercise improved this function and was beneficial on anxiety-like symptoms. As FA are present in neuronal membrane phospholipids and play a critical role in brain function, our results suggest that low incorporation of trans FA in neuronal membranes may act on cortical and hippocampal Na(+)K(+)-ATPase activity, but this change appears to be unrelated to the behavioral parameters primarily harmed by consumption of trans and less so by saturated FA, which were reversed by exercise.

Oxidative stress and anxiety-like symptoms related to withdrawal of passive cigarette smoke in mice: beneficial effects of pecan nut shells extract, a by-product of the nut industry.

The present study evaluated the role of pecan nut (Carya illinoensis) shells aqueous extract (AE) against oxidative damage induced by cigarette smoke exposure (CSE) and behavioral parameters of smoking withdrawal. Mice were passively exposed to cigarette smoke for 3 weeks (6, 10, and 14 cigarettes/day) and orally treated with AE (25 g/L). CSE induced lipid peroxidation in brain and red blood cells (RBC), increased catalase (CAT) activity in RBC, and decreased plasma ascorbic acid levels. AE prevented oxidative damage and increased antioxidant defenses of mice exposed to cigarette smoke. In addition, AE reduced the locomotor activity and anxiety symptoms induced by smoking withdrawal, and these behavioral parameters showed a positive correlation with RBC lipid peroxidation. Our results showed the beneficial effects of this by-product of the pecan industry, indicating its usefulness in smoking cessation.