Embryo-larval exposure to atrazine reduces viability and alters oxidative stress parameters in Drosophila melanogaster.

The herbicide atrazine has been used worldwide with subsequent residual contamination of water and food, which may cause adverse effects on non-target organisms. Animal exposure to this herbicide may affect development, reproduction and energy metabolism. Here, the effects of atrazine regarding survival and redox metabolism were assessed in the fruit fly D. melanogaster exposed during embryonic and larval development. The embryos (newly fertilized eggs) were exposed to different atrazine concentrations (10µM and 100µM) in the diet until the adult fly emerged. Pupation and emergence rates, developmental time and sex ratio were determined as well as oxidative stress parameters and gene expression of the antioxidant defence system were evaluated in newly emerged male and female flies. Atrazine exposure reduced pupation and emergence rates in fruit flies without alterations to developmental time and sex ratio. Different redox imbalance patterns were observed between males and females exposed to atrazine. Atrazine caused an increase in oxidative damage, reactive oxygen species generation and antioxidant capacity and decreased thiol-containing molecules. Further, atrazine exposure altered the mRNA expression of antioxidant genes (keap1, sod, sod2, cat, irc, gss, gclm, gclc, trxt, trxr-1 and trxr-2). Reductions in fruit fly larval and pupal viability observed here are likely consequences of the oxidative stress induced by atrazine exposure.

Inflammatory response after session of resistance exercises in untrained volunteers / Resposta inflamatória após sessão de exercícios resistidos em voluntários destreinados

The present study aimed to investigate the interaction between the blood cells, inflammatory markers, oxidative stress parameters and delayed onset muscle soreness (DOMS) after a session of resistance exercise (SRE). The sample consisted of sixteen untrained men (26.4±5 years; 25.9±3 kg m- 2). The SRE was composed of 4 sets of 10 repetitions maximum (extensor bench, squat and leg press) for each exercise. Complete blood cell count, C-reactive protein (CRP), creatine kinase (CK), lipid peroxidation and antioxidant capacity against peroxyl radicals were previously evaluated (baseline), and at 0, 30 and 120 min. after the SRE. DOMS was assessed 24 hours after the exercises. Immediately after the SRE, an increase of blood cell number was observed; returning to baseline after 30 min. However, after 120 min., neutrophils showed higher values than the baseline and 30 min. assessments. CK and CRP increased progressively throughout the experiment. LPO increased immediately and 120 min. after the SRE. Untrained volunteers presented an apparent biphasic inflammatory response after an acute SRE and the changes in oxidative stress, inflammatory markers and leukocytosis were best evidenced two hours after exercise.

O presente estudo investigou a interação entre as células sanguíneas, marcadores inflamatórios, parâmetros de estresse oxidativo e dor muscular de início tardio (DMIT) após uma sessão de exercícios de resistência (SER). A amostra compreendeu dezesseis voluntários destreinados (26.4±5 anos; 25.9±3 kg m-2). A SER consistiu em 4 séries de 10 repetições máximas (extensão do joelho, agachamento e leg press) para cada exercício. Hemograma completo, proteína C-reativa (PCR), creatina kinase (CK), lipoperoxidação e capacidade antioxidante contra o radical peroxil foram avaliados previamente (basal), 0, 30 e 120 min. após a SER. A DMIT foi avaliada 24h após os exercícios. Imediatamente após a SER ocorreu um aumento no número de células sanguíneas, retornando aos valores basais após 30 min. Entretanto, após 120 min. os neutrófilos apresentaram valores mais elevados que as avaliações basais e 30 min. A CK e a PCR aumentaram progressivamente ao longo do experimento. A liperoxidação aumentou imediatamente e 120 min. após a SER. Voluntários destreinados apresentam uma aparente resposta inflamatória bifásica após SER e as alterações dos parâmetros de estresse oxidativo, marcadores inflamatórios e leucocitose são melhor evidenciadas duas horas após os exercícios.

GH overexpression modifies muscle expression of anti-oxidant enzymes and increases spinal curvature of old zebrafish.

Growth hormone (GH) excess causes an increment in the metabolic rate and in reactive oxygen species generation, which accelerate the ageing process in mammals. Considering that there is no information on this subject in fish, the aim of the present study was to evaluate the excess GH effect on senescence in a zebrafish (Danio rerio) transgenic model. In order to reach this objective, we analyzed the phenotype of spinal curvature and expression of genes related to the anti-oxidant defense system and myogenesis in muscle of 8 and 30 months old GH-transgenic males. Gene expression analyses revealed that both superoxide dismutase isoforms were down-regulated only in 30 months old animals, while glutamate cysteine ligase was down-regulated in GH-transgenic zebrafish. Acceleration of the spinal curvature and a reduction in the expression of miogenin at both ages and MyoD in the old fish were also observed. Although neurolipofuscin accumulation was not significant in GH-transgenic zebrafish, the estimation of maximum longevity based on the von Bertalanffy growth function was significantly lower in this group. The results obtained here indicate that GH overexpression reduces the transcription of anti-oxidant defense system and myogenesis-related genes, which probably accelerates senescence in the zebrafish transgenic model used.