Učinci nanočestica željezova oksida na antioksidacijski kapacitet i odgovor na oksidacijski stres u mozambičke tilapije (Oreochromis mossambicus, Peters 1852)

Recent research has raised concern about the biocompatibility of iron oxide nanoparticles (IONPs), as they have been reported to induce oxidative stress and inflammatory responses, whilst prolonged exposure to high IONP concentrations may lead to cyto-/genotoxicity. Besides, there is concern about its environmental impact. The aim of our study was to investigate the effects of IONPs on the antioxidant defence system in freshwater fish Mozambique tilapia (Oreochromis mossambicus, Peters 1852). The fish were exposed to IONP concentration of 15 mg/L over 1, 3, 4, 15, 30, and 60 days and the findings compared to a control, unexposed group. In addition, we followed up the fish for 60 days after exposure had stopped to estimate the stability of oxidative stress induced by IONPs. Exposure affected the activity of antioxidant and marker enzymes and increased the levels of hydrogen peroxide and lipid peroxidation in the gill, liver, and brain tissues of the fish. Even after 60 days of depuration, adverse effects remained, indicating long-term nanotoxicity. Moreover, IONPs accumulated in the gill, liver, and brain tissues. Our findings underscore the potential health risks posed to non-target organisms in the environment, and it is imperative to establish appropriate guidelines for safe handling and disposal of IONPs to protect the aquatic environment.Nedavna istraživanja izazvala su zabrinutost oko biokompatibilnosti nanočestica željezova oksida (engl. iron oxide nanoparticles – IONP), nakon što je utvrđeno da izazivaju oksidacijski stres i upalni odgovor, a produljena izloženost visokim koncentracijama IONP-a može dovesti do cito-/genotoksičnosti. Osim toga, postoji i zabrinutost u pogledu njihova utjecaja na okoliš. Cilj ovog istraživanja bio je proučiti djelovanje IONP-a na antioksidacijski obrambeni sustav slatkovodne ribe mozambičke tilapije (Oreochromis mossambicus, Peters 1852). Ribe su bile izložene koncentraciji IONP-a od 15 mg/L tijekom 1, 3, 4, 15, 30 i 60 dana, a usporedno su praćene i jedinke kontrolne, neizložene skupine. Nadalje, praćenje je nastavljeno tijekom 60 dana nakon prestanka izloženosti kako bismo procijenili stabilnost oksidacijskoga stresa izazvanoga IONP-om. Izloženost je utjecala na aktivnost antioksidacijskih i markerskih enzima te povećala razine vodikova peroksida i lipidne peroksidacije u tkivu ribljih škrga, jetre i mozga. Čak i nakon 60 dana „čišćenja“ zaostali su štetni učinci, koji upozoravaju na nepovratnu nanotoksičnost. Štoviše, IONP se akumulirao u tkivu škrga, jetre i mozga. Naša otkrića naglašavaju potencijalne zdravstvene rizike za neciljane organizme u okolišu, te je nužno uspostaviti odgovarajuće smjernice za sigurno rukovanje i odlaganje IONP-a kako bi se zaštitio vodeni okoliš

DNA methylation at the mu-1 opioid receptor gene (OPRM1) promoter predicts preoperative, acute, and chronic postsurgical pain after spine fusion.

INTRODUCTION:The perioperative pain experience shows great interindividual variability and is difficult to predict. The mu-1 opioid receptor gene (OPRM1) is known to play an important role in opioid-pain pathways. Since deoxyribonucleic acid (DNA) methylation is a potent repressor of gene expression, DNA methylation was evaluated at the OPRM1 promoter, as a predictor of preoperative, acute, and chronic postsurgical pain (CPSP). METHODS:A prospective observational cohort study was conducted in 133 adolescents with idiopathic scoliosis undergoing spine fusion under standard protocols. Data regarding pain, opioid consumption, anxiety, and catastrophizing (using validated questionnaires) were collected before and 2-3 months postsurgery. Outcomes evaluated were preoperative pain, acute postoperative pain (area under curve [AUC] for pain scores over 48 hours), and CPSP (numerical rating scale >3/10 at 2-3 months postsurgery). Blood samples collected preoperatively were analyzed for DNA methylation by pyrosequencing of 22 CpG sites at the OPRM1 gene promoter. The association of each pain outcome with the methylation percentage of each CpG site was assessed using multivariable regression, adjusting for significant (P<0.05) nongenetic variables. RESULTS:Majority (83%) of the patients reported no pain preoperatively, while CPSP occurred in 36% of the subjects (44/121). Regression on dichotomized preoperative pain outcome showed association with methylation at six CpG sites (1, 3, 4, 9, 11, and 17) (P<0.05). Methylation at CpG sites 4, 17, and 18 was associated with higher AUC after adjusting for opioid consumption and preoperative pain score (P<0.05). After adjusting for postoperative opioid consumption and preoperative pain score, methylation at CpG sites 13 and 22 was associated with CPSP (P<0.05). DISCUSSION:Novel CPSP biomarkers were identified in an active regulatory region of the OPRM1 gene that binds multiple transcription factors. Inhibition of binding by DNA methylation potentially decreases the OPRM1 gene expression, leading to a decreased response to endogenous and exogenous opioids, and an increased pain experience

Evaluation of Genetic Damage in Oreochromis mossambicus Exposed to Selected Nanoparticles by Using Micronucleus and Comet Bioassays

The purpose of the present study is to extend knowledge on the adverse effects of nanoparticles by evaluating genotoxicity as environmental risk assessment in Oreochromis mossambicus. Fish were exposed to sublethal concentrations of the selected nanoparticles, namely silicon dioxide (SiO2NPs-12mg/L), aluminium oxide (Al2O3NPs-4mg/L), titanium dioxide (TiO2NPs-16.4mg/L) and iron oxide (Fe3O4NPs-15mg/L) for short-term (24, 72 and 96 h) and long-term durations (15, 30 and 60 days). Genetic damages such as cytoplasmic, nuclear and DNA damage were measured in the erythrocytes of fish by using standard genotoxicity tests such as micronucleus test and comet assay. The frequencies of micronuclei along with nuclear and cytoplasmic abnormalities were scored and compared with the control group. The intensity of micronuclei along with other nuclear and cytoplasmic anomalies are found to be increased significantly (p<0.05) in time-dependent manner in all exposure groups when compared to the control group, thereby indicating chromosomal damage as a result of contact with nanoparticles. The tail length and percent of tail DNA within the comet significantly (p<0.05) increased in time-dependant manner after exposure to all nanoparticles, demonstrating an increase in DNA damage. Taken together, by using micronucleus test and comet assay, it is evident that the selected nanoparticles at sublethal concentrations induced genetic damage in Oreochromis mossambicus