Aortic Response to Strength Training and Spirulina platensis Dependent on Nitric Oxide and Antioxidants

Studies have shown that supplementation with Spirulina platensis improves vascular reactivity. However, it is unclear whether in association with strength training this effect can be enhanced. Thus, this study aimed to determine the effects of strength training and S. platensis on the reactivity of the aorta from Wistar rat and the possible mechanisms involved. The animals were supplemented with S. platensis and divided into sedentary (SG, SG50, SG150, and SG500) and trained groups (TG, TG50, TG150, and TG500). Nitrite, malondialdehyde (MDA) and antioxidant activity were determined by biochemical assays. To evaluate vascular response, cumulative concentration—response curves to phenylephrine (PHE) and acetylcholine (ACh) were constructed. L-NAME was used to assess the participation of nitric oxide (NO). It was observed that the PHE contractile potency was reduced in TG50, TG150, and TG500 groups compared to SG50, SG150, and SG500 groups, respectively. However, the presence of L-NAME increased the contractile response in all groups. Strength training potentiated the increase in relaxing activity induced by S. platensis, where the pCE50 values of ACh increased in TG150 and TG500. These responses were accompanied by increased nitrite production, MDA reduction and increased antioxidant activity in the aorta of both TG150 and TG500 groups. Thus, the present study demonstrated that combined with strength training, S. platensis potentiates vascular improvement through the participation of NO and reduction of oxidative stress

CARBOHYDRATE SUPPLEMENTATION ATTENUATES DECREMENT OF PERFORMANCE IN OVERTRAINED RATS

Although carbohydrate ingestion at the end of single exercises is recognized to delays fatigue and accelerates recovery, if chronic ingestion can prevent overtraining during periods of intense training is something not yet elucidated. The present study aimed to determine whether carbohydrate supplementation minimize overtraining in Wistar rats. The animals underwent 11 weeks of training (running) on a treadmill, and the last 3 weeks were designed to induce overtraining. One group was supplemented with carbohydrates (EX-CHO; n=13), one group had no supplementation (EX; n=10), and another group remained inactive (C; n=9). Performance tests (Pr) were given before training (Pr1) and at the 8th (Pr2) and 11th training week (Pr3). Food intake, body weight, testosterone, cortisol, malondialdehyde, creatine kinase (CK) and activities of PI3-K, Akt-1, mTOR and GSK-3 enzymes were measured. In the EX group, there was a significant 32.6% performance decrease at Pr3 compared to Pr2. Additionally, at protocol completion, the EX-CHO group had a greater gastrocnemius weight than the C group (p=0.02), which did not occur in the EX group. Training caused anorexia, decreased testosterone (p=0.001) and increased malondialdehyde (p=0.009) in both exercise groups compared to C, without an influence of carbohydrate supplementation on these variables (p>0.05). The activity of Akt-1 was higher in the EX-CHO group but not the EX group compared to the C group (p=0.013). Carbohydrate supplementation promoted an attenuation in the performance decrement and maintained gastrocnemius muscle mass in animals that had undergone overtraining protocols, which was accompanied by increased activity of the Akt-1 molecular indicator.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author