The implications of exercise in Drosophila melanogaster: insights into Akt/p38 MAPK/Nrf2 pathway associated with Hsp70 regulation in redox balance maintenance.

This study investigated the potential effects of exercise on the responses of energy metabolism, redox balance maintenance, and apoptosis regulation in Drosophila melanogaster to shed more light on the mechanisms underlying the increased performance that this emerging exercise model provides. Three groups were evaluated for seven days: the control (no exercise or locomotor limitations), movement-limited flies (MLF) (no exercise, with locomotor limitations), and EXE (with exercise, no locomotor limitations). The EXE flies demonstrated greater endurance-like tolerance in the swimming test, associated with increased citrate synthase activity, lactate dehydrogenase activity and lactate levels, and metabolic markers in exercise. Notably, the EXE protocol regulated the Akt/p38 MAPK/Nrf2 pathway, which was associated with decreased Hsp70 activation, culminating in glutathione turnover regulation. Moreover, reducing the locomotion environment in the MLF group decreased endurance-like tolerance and did not alter citrate synthase activity, lactate dehydrogenase activity, or lactate levels. The MLF treatment promoted a pro-oxidant effect, altering the Akt/p38 MAPK/Nrf2 pathway and increasing Hsp70 levels, leading to a poorly-regulated glutathione system. Lastly, we demonstrated that exercise could modulate major metabolic responses in Drosophila melanogaster aerobic and anaerobic metabolism, associated with apoptosis and cellular redox balance maintenance in an emergent exercise model.

Modulation of glutamate levels and Na+,K+-ATPase activity contributes to the chrysin memory recovery in hypothyroidism mice.

Abnormalities in the thyroid hormones, like in hypothyroidism, are closely related to dementia and Alzheimer's disease demonstrating the main symptom of these disorders: memory deficit. In this study we evaluated the effect of chrysin on deficit spatial and aversive memories and the contribution of glutamatergic, cholinergic pathways and Na+, K+-ATPase activity on hippocampus and prefrontal cortex in hypothyroid adult female mice C57BL/6. Hypothyroidism was induced by the continuous exposure to 0.1% methimazole (MTZ) in drinking water for 31 days. The exposure to MTZ was associated to low plasma levels of thyroid hormones (TH) compared to the control group on the 32nd. Subsequently, euthyroid and MTZ-induced hypothyroid mice received (intragastrically) either vehicle or chrysin (20 mg/kg) once a day for 28 consecutive days. After treatments mice performed the following behavioral assessments: open-field test (OFT), morris water maze (MWM) and passive avoidance test. Additionally, plasma TH levels were measured again, as well as glutamate levels, Na+,K+-ATPase and acetylcholinesterase (AChE) activities were analyzed in the hippocampus and prefrontal cortex of mice. Mice with hypothyroidism showed a deficit of spatial and aversive memory and chrysin treatment reversed these deficits. It also reduced the levels of glutamate and decreased Na+,K+-ATPase activity in both cerebral structures in the hypothyroid mice compared with the euthyroid ones, with the exception of glutamate in the hippocampus, which was a partial reversal. AChE activity was not altered by treatments. Together, our results demonstrate that chrysin normalized hippocampal glutamate levels and Na+,K+-ATPase activity, which could be involved in the reversal of memory deficit.

Hesperidin attenuates iron-induced oxidative damage and dopamine depletion in Drosophila melanogaster model of Parkinson's disease.

This study has evaluated the action of flavonoid hesperidin on the neurotoxic effects caused by the intake of iron (Fe) in Drosophila melanogaster. Male adult flies, aged 1-3 days, have been divided into four groups of 50 each: (1) control, (2) Hsd 10 µM, (3) Fe 20 mM (4) Hsd 10 µM + Fe 20 mM. During the exposure protocol, the flies have been exposed to a diet containing Hsd and/or Fe for 48 h. The survival and behavioral analyses have been carried out in vivo, and ex vivo. The analyses involved acetylcholinesterase (AChE) activity and Fe levels in the flies' heads and bodies and determination of dopaminergic levels, cellular and mitochondrial viability, activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reactive species levels (RS), thiobarbituric acid reactive substances (TBARS) and contents of total thiols and non-proteic thiols (NPSH) in the flies' heads. A significant negative correlation between Fe levels in the head of the flies and the survival, dopamine levels and antioxidant enzymes in the head of the flies has been found. Additionally, significant positive correlation between Fe levels in the head of the flies with negative geotaxis RS and AChE activity in the head of the flies has been found. It demonstrates that the flies which had higher levels of Fe in their heads have demonstrated more susceptibility to neurotoxicity. An important result from our study is that Hsd treatment promotes a decrease in Fe concentration in the head, restores dopamine levels and cholinergic activity of the flies and improves motor function caused by Fe. Hsd also ameliorates Fe induced mortality, oxidative stress and mitochondrial dysfunction. Our results have demonstrated the neuroprotective effect of Hsd and it suggests that flavonoid acts in different ways to protect against the Parkinson disease caused by Fe exposure such as the direct scavenging of RS and activation of antioxidant enzymes.