Effects of Vitamin C on the Prevention of Ischemia-Reperfusion Brain Injury: Experimental Study in Rats

Background. Reperfusion syndrome after carotid endarterectomy is a complication associated with cerebrovascular self-regulation in a chronically hypoperfused cerebral hemisphere, leading to severe neurological damage. Vitamin C is an important antioxidant in brain metabolism that has shown some neuroprotective actions. Objective. To investigate the potential effects of vitamin C on cerebral reperfusion in comparison with placebo (saline) in rats. Methods. Male Wistar rats were divided into 3 groups: (i) Sham (n=4), animals exposed to carotid arteries dissection without clamping; (ii) Control (n=4), animals that received an intraperitoneal injection of 0.9% saline solution (0.1 mL/kg) and underwent carotid arteries dissection with temporary clamping; (iii) Vitamin C (n=4), animals that received an intraperitoneal injection of vitamin C (750 mg/kg) and underwent carotid arteries dissection with temporary clamping. Behavioral assessment was then performed in all groups, which included the open field, Morris water maze and rotarod tests. Levels of malondialdehyde (MDA) in the hippocampus and striatum were measured using a fluorometric assay. Results. Rats treated with vitamin C presented with a similar behavior as compared to the Sham group in all the three tests (p>0.05), but it was significantly different from controls (p<0.05). Vitamin C was also found to reduce MDA levels in both hippocampus and striatum when compared to placebo (p<0.05). Conclusion. In the present study, vitamin C was associated with behavioral and motor preservation as well as decreased cerebral MDA levels after induced cerebral ischemia in rats

Long-term high-protein diet intake reverts weight gain and attenuates metabolic dysfunction on high-sucrose-fed adult rats

Abstract Background Consumption of added sugars has been considered a worldwide public health concern by its association with metabolic syndrome and its comorbidities. Meanwhile, current studies have suggested high-protein diets to promote weight loss and improved metabolic outcomes. Thus, this study aimed to investigate the effects of long-term high-protein diet (HPD, 34.3% protein) intake on high-sucrose-fed rats. Methods Weaned male Wistar rats were randomized into two groups: rats fed a standard chow (CT/CT, 10% sucrose) or rats fed a high-sucrose diet (HSD, 25% sucrose) for a 20-week observational period. Subsequently, HS/HS animals were randomized into 3 new groups: rats maintained on HSD diet (HS/HS); rats submitted to HSD replacement by standard chow (HS/CT); and those with HSD replaced by HPD (HS/HP). All groups were followed up for 12 weeks during which we investigated the effects of HPD on body weight, energy intake, obesity development, glicemic/lipid profile, glucose tolerance, insulin resistance, tissue weight (adipose tissue, liver and skeletal muscles), lipolytic activity, liver lipoperoxidation and histology, as well as serum markers of hepatic function. Results Post-weaning exposure to HSD led to metabolic syndrome phenotype at adulthood, herein characterized by central obesity, glucose intolerance, dyslipidaemia and insulin resistance. Only HPD feeding was able to revert weight gain and adipose tissue accumulation, as well as restore adipose tissue lipolytic response to sympathetic stimulus. On the other hand, either HPD or withdrawal from HSD promoted very similar metabolic outcomes upon 12-week nutritional intervention. HS/HP and HS/CT rats showed reduced fasting serum levels of glucose, triacylglycerol and total cholesterol, which were correlated with the improvement of peripheral insulin sensitivity, as inferred from kITT and TyG Index values. Both nutritional interventions restored liver morphofunctional patterns, but only HPD restored lipid peroxidation. Conclusions Our data showed that 12-week intake of an isocaloric moderately high-protein diet consistently restored high-sucrose-induced central adiposity and obesity in addition to the attenuation of other important metabolic outcomes, such as improvement of glucolipid homeostasis associated to increased insulin sensitivity and reversal of hepatic steatosis. On the other hand, simple withdrawal from high-sucrose consumption also promoted the abovementioned metabolic outcomes with no impact on body weight