Evaluation of urinary 8-hydroxy-2-deoxyguanosine level in experimental Alzheimer's disease: Impact of carvacrol nanoparticles

Abstract

The present study aimed to compare the effect of carvacrol essential oil and carvacrol nanoemulsion against experimental Alzheimer's (AD). Forty male albino rats were used and divided into four groups as follow: control, AlCl₃ induced AD, carvacrol oil treated and carvacrol nanoemulsion treated groups. Brain nor-epinephrine, serotonin and dopamine were analyzed by high performance liquid chromatography (HPLC). Levels of brain Thiobarbituric acid-reactive substances (TBARS), Superoxide dismutase (SOD), reduced glutathione (GSH), cholinesterase, and advanced oxidation protein product (AOPP) were evaluated. Urinary 8-hydroxyguanosine (8-OHdG) level was evaluated by HPLC. Brain Cyclooxygenase 1 and 2 (COX 1and 2) were analyzed by immunohistochemistry. AD induced by AlCl₃ in rats was depicted by the significant increase in the neurotransmitters levels which is accompanied with high degree of oxidative stress that was revealed in the elevated level of urinary 8-OHdG along with significant elevation in AOPP, TBARS, and cholinesterase levels and a significant decrease in SOD and GSH; these results are confirmed by immunohistochemistry analysis of COX 1 and 2. On the other hand, the treatment with carvacrol oil and carvacrol nanoemulsion were capable of mitigate effects mediated by AlCl₃ administration in treated rats. While the treatment with both approached succeeded to retract the negative impact of AlCl₃; but the effect of carvacrol nanoemulsion was more notable than the essential oil. Carvacrol oil and carvacrol nanoemulsion were eminent to overturn AlCl₃ induced brain AD which could be imputed to antioxidant and anti-inflammatory capabilities of carvacrol to alter oxidative stress effect. In extension; carvacrol nanoemulsion were evident to give more effective and efficient way in carvacrol delivery to pass through blood brain barriers and ameliorate brain changes.

Keywords: 8-hydroxy-2-deoxyguanosine; Advanced oxidation protein product; Alzheimer’s disease; Carvacrol nanoemulsion; Cyclooxygenases; Neurotransmitters.