Metformin can act in muscle, inhibiting the complex I of the electron transport chain and decreasing mitochondrial reactive oxygen species. Our hypothesis is that the inhibition of complex I can minimize damage oxidative in muscles of hypoinsulinemic rats. The present study investigated the effects of insulin and/or metformin treatment on oxidative stress levels in the gastrocnemius muscle of diabetic rats. Rats were rendered diabetic (D) with an injection of streptozotocin and were submitted to treatment with insulin (D+I), metformin (D+M), or insulin plus metformin (D+I+M) for 7 days. The body weight, glycemic control, and insulin resistance were evaluated. Then, oxidative stress levels, glutathione antioxidant defense system, and antioxidant status were analyzed in the gastrocnemius muscle of hypoinsulinemic rats. The body weight decreased in D+M compared to ND rats. D+I and D+I+M rats decreased the glycemia and D+I+M rats increased the insulin sensitivity compared to D rats. D+I+M reduced the oxidative stress levels and the activity of catalase and superoxide dismutase in skeletal muscle when compared to D+I rats. In conclusion, our results reveal that dual therapy with metformin and insulin promotes more benefits to oxidative stress control in muscle of hypoinsulinemic rats than insulinotherapy alone.

No abstract

The increase in antioxidant responses promoted by regular physical activity is strongly associated with the attenuation of chronic oxidative stress and physiological mechanisms related to exercise adaptation. The aim of this work was to evaluate and compare how different exercise protocols (HIIE: high-intensity interval exercise, CE: continuous exercise, and RE: resistance exercise) may alter salivary and plasmatic antioxidants and salivary markers of exercise intensity and nitric oxide. Thirteen healthy, trained male subjects were submitted to the three exercise protocols. Blood and saliva samples were collected at the points preexercise, postexercise, and 3 hours postexercise. Antioxidants (total antioxidant capacity, superoxide dismutase and catalase activities, and levels of reduced glutathione and uric acid), markers of exercise intensity (salivary total protein and amylase activity), and salivary nitric oxide were evaluated. As a result, all exercise protocols increased the markers of exercise intensity and nitric oxide. Antioxidant response was increased after exercise, and it was found that a single HIIE session exerts a similar pattern of antioxidant response compared to CE, in plasma and saliva samples, while RE presented minor alterations. We suggest that HIIE may lead to alterations in antioxidants and consequently to the physiological processes related to redox, similar to the CE, with the advantage of being performed in a shorter time. In addition, the antioxidant profile of saliva samples showed to be very similar to that of plasma, suggesting that saliva may be an alternative and noninvasive tool in sports medicine for the study of antioxidants in different physical exercise protocols.

The consumption of royal jelly (RJ) determines the differences between castes and behavioral development in the honeybee Apis mellifera. However, it is not known whether the proteins of RJ are related to these differences, or which proteins are responsible for the changes. To understand the functions of RJ proteins that are present in other tissues of the bee, in addition to hypopharyngeal gland, we used a polyclonal antibody anti-MRJP1 to investigate the presence of this protein in nervous system of honeybee. This study showed the presence of three polypeptides (p57, p70 and p128) in specific tissues of bee brain. Mushroom body, optic lobe and antennal lobe neuropils all contained proteins recognized by anti-MRJP1. Proteomic analysis showed that the three polypeptides are correlated with proteins of the MRJP family. p57 is correlated with MRJP1, p70 with MRJP3, while p128 may be an oligomeric form or a new polypeptide. Immunostaining of the brain and hypopharyngeal gland revealed differential expression of MRJPs in various brain regions and in different honeybee castes and subcastes. The identification and localization of these MRJPs contribute to the elucidation of the biological roles of this protein family.

No abstract

This study tested the effect of isoflavone supplementation in addition to combined exercise training on plasma lipid levels, inflammatory markers and oxidative stress in postmenopausal women. Thirty-two healthy and non-obese postmenopausal women without hormone therapy were randomly assigned to exercise + placebo (PLA; n = 15) or exercise + isoflavone supplementation (ISO; n = 17) groups. They performed 30 sessions of combined exercises (aerobic plus resistance) over ten weeks and consumed 100 mg of isoflavone supplementation or placebo. Blood samples were collected after an overnight fast to analyze the lipid profile, interleukin-6 (IL-6), interleukin-8 (IL-8), superoxide dismutase (SOD), total antioxidant capacity (FRAP), and thiobarbituric acid reactive substances (TBARS), before and after ten weeks of the intervention. There were no differences in the changes (pre vs. post) between groups for any of the inflammatory markers, oxidative stress markers or lipid profile variables. However, interleukin-8 was different between pre- and post-tests (p < 0.001) in both groups (Δ = 7.61 and 5.61 pg/mL) as were cholesterol levels (p < 0.05), with no interaction between groups. The combination of isoflavone supplementation and exercise training did not alter oxidative stress markers in postmenopausal women, but exercise training alone may increase IL-8 and decrease total cholesterol levels.

Nitrate (NO3−) supplementation is associated with exercise performance, oxygen uptake, blood flow, and blood pressure improvement, and it can act as an antioxidant agent. This study evaluated the effects of sodium nitrate supplementation on oxidative stress markers and blood pressure responses after aerobic exercise performance in physically active males. Fourteen subjects aged 22±3 years and with a BMI of 23±1 kg/m2 were submitted to four exercise tests in intervals of 5 days. Nitrate supplementation (NO session) and placebo supplementation (PL session) were acute (AC) and over a period of 5 days (FD) in random order with a crossover design. Saliva was collected at basal (0′); 60 min after supplementation (60′); immediately after exercise (90′); and 15, 30, and 60 min after the test (105′, 120′, and 150′). The NO session had higher concentrations (P<0.05) of salivary nitrite in both AC and FD treatments when compared with the PL session. There was a reduction in systolic blood pressure (SBP) only after FD in the NO session. Furthermore, uric acid and total antioxidant capacity (FRAP) salivary concentrations increased, while SOD activity and TBARS levels decreased after FD but not after AC in the NO session. The results suggest that nitrate supplemented over a period of 5 days reduced SBP and indirectly acted as an antioxidant in healthy nonsedentary young men.

A polyphenol-enriched fraction from Annona crassiflora fruit peel (Ac-Pef) containing chlorogenic acid, (epi)catechin, procyanidin B2, and caffeoyl-glucoside was investigated against hepatic oxidative and nitrosative stress in streptozotocin-induced diabetic rats. Serum biochemical parameters, hepatic oxidative and nitrosative status, glutathione defense system analysis, and in silico assessment of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the main compounds of Ac-Pef were carried out. Ac-Pef treatment during 30 days decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities, as well as hepatic lipid peroxidation, protein carbonylation and nitration, inducible nitric oxide synthase level, and activities and expressions of glutathione peroxidase, superoxide dismutase, and catalase. There were increases in antioxidant capacity, glutathione reductase activity, and reduced glutathione level. ADMET predictions of Ac-Pef compounds showed favorable absorption and distribution, with no hepatotoxicity. A. crassiflora fruit peel showed hepatoprotective properties, indicating a promising natural source of bioactive molecules for prevention and therapy of diabetes complications.