Iron oxide nanoparticle (IONP) therapy has diverse health benefits but high doses or prolonged therapy might induce oxidative cellular injuries especially in the brain. Therefore, we conducted the current study to investigate the protective role of quercetin supplementation against the oxidative alterations induced in the brains of rats due to IONPs. Forty adult male albino rats were allocated into equal five groups; the control received a normal basal diet, the IONP group was intraperitoneally injected with IONPs of 50 mg/kg body weight (B.W.) and quercetin-treated groups had IONPs + Q25, IONPs + Q50 and IONPs + Q100 that were orally supplanted with quercetin by doses of 25, 50 and 100 mg quercetin/kg B.W. daily, respectively, administrated with the same dose of IONPs for 30 days. IONPs induced significant increases in malondialdehyde (MDA) and significantly decreased reduced glutathione (GSH) and oxidized glutathione (GSSG). Consequently, IONPs significantly induced severe brain tissue injuries due to the iron deposition leading to oxidative alterations with significant increases in brain creatine phosphokinase (CPK) and acetylcholinesterase (AChE). Furthermore, IONPs induced significant reductions in brain epinephrine, serotonin and melatonin with the downregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and mitochondrial transcription factor A (mtTFA) mRNA expressions. IONPs induced apoptosis in the brain monitored by increases in caspase 3 and decreases in B-cell lymphoma 2 (Bcl2) expression levels. Quercetin supplementation notably defeated brain oxidative damages and in a dose-dependent manner. Therefore, quercetin supplementation during IONPs is highly recommended to gain the benefits of IONPs with fewer health hazards.

Iron oxide nanoparticles (IONPs), because of their superparamagnetic characteristics, are of considerable interest in nanotechnology related fields including biomedical, environmental, industrial applications. however, the knowledge of IONPs toxicity is very limited especially in vivo studies. Quercetin (QT); a natural flavonoid , strong antioxidant , free radical scavenger and iron chelator, has multiple therapeutic effects. The present study aimed to explore role of IONPs and QT in rat body weight and possible protective effect of QT in chelating iron preventing fenton reaction. Twenty five male adult rats were allocated equally into five groups: control, IONPs (50 mg/kg b.w i.p. 3 times/week), QT (25 mg/kg b.w. daily per os)+IONPs, QT (50 mg/kg b.w. daily per os) + IONPs, QT (100 mg/kg b.w. daily per os) + IONPs. Rat body weights were assessed weekly till end of the study. after the 30 days brain tissues were collected for measurement of iron level. IONPs induced a non-significant difference in all weeks except at day of sacrifice there was a significant increment in body weight. Compared to IONPs group, QT 25, 50 and 100 mg/kg b.w.+IONPs induced a non-significant difference in body weight in all weeks. IONPs induced a significant increment in Fe level. Compared to IONPs group, QT 25, 50 and 100 mg/kg+IONPs induced a non-significant reduction in Fe level. the results of this study showed role of IONPs and quercetin in body weight gain and suggested protective role of quercetin in chelating Fe preventing fenton reaction occurred from its increase by IONPs.