RESUMO
Noise is an environmental stressor which causes distress and hearing loss in individuals residing in urban areas. Psychological deficits such as anxiety, depression, impaired memory and cognitive decline are caused by noise stress. Different vitamins have been used as a potential antioxidant for neuronal protection. In this study we investigate the anxiolytic, antidepressant and memory enhancing effect of vitamin D2 (Vit D2) following noise stress. Thirty-six albino rats were randomly divided into six groups. (i) Unstressed + corn oil (ii) Unstressed + Vit D2 (iii) Acute noise stress + corn oil (iv) Acute noise stress + Vit D2 (v) Repeated noise stress + corn oil (vi) Repeated noise stress + Vit D2. 600 IU/kg body weight of Vit D2 dosage was prepared in corn oil. Corn oil is used as vehicle and all the drugs administered via oral gavage till end of the experiment (day 16). Recorded sound of generator which was amplified by speakers and had 100 dB intensity was used as noise stress. Repeated stressed animals were exposed to noise (4-hrs) daily for 14 days, while acute stressed animals were exposed to noise (4-hrs) once after 14 days. Behavioral tests (elevated plus maze, light dark box, tail suspension test and Morris water maze) of all groups were performed after15 days treatment period. After behavioral tests rats received their last dosage and decapitated after 1-hr. Brain of all animals was removed and used for biochemical (oxidative stress biomarker, antioxidant enzymes and acetylcholinesterase) and histopathological estimations. Results show that Vit D2 decreased time spent in light box and open arm of light dark activity box and elevated plus maze test respectively (used for anxiety evaluation), decreased immobility time in tail suspension test (for depression) and improved cognitive ability evaluated by Morris water maze test in acute and repeated noise stressed rats. Furthermore, increased antioxidant enzymes activity, decreased lipid peroxidation and acetylcholinesterase activity were also observed in Vit D2 treated animals following acute and repeated noise stress. Normalization in histopathological studies was also observed in Vit D2 treated following acute and repeated noise stress. It is concluded that Vit D2 protects from noise stress induced behavioral, biochemical and histopathological impairment through its antioxidant potential.
RESUMO
Thymoquinone (Tq), an active compound of Nigella sativa, has been known for its anti-inflammatory, antioxidant, and neuroprotective characteristics. The present study is aimed to evaluate the effect of Tq on reserpine (Rsp)-induced behavioral (anxiety and/or depression) and, memory deficit; hippocampal inflammatory markers, oxidative markers, antioxidant enzymes, acetylcholinesterase (AChE) activity and histopathology in male mice. Animals were injected with Rsp at a dose of 2 mg/ml/kg and doses of Tq (10 and 20 mg/ml/kg) for 28 days. After the treatment period, behavioral tests [Elevated plus maze (Epm); Light dark box test (Lda); Morris water maze (Mwm); Forced swim test (Fst); Tail suspension test (Tst)] were conducted. After analysis of behaviors, mice were decapitated and brain samples were collected, the hippocampus was removed from the whole-brain sample for biochemical analysis and histology. Administration of Tq at both doses prevent adverse effects of Rsp and increased time spent in open arm and lightbox in Lda and Epm respectively, decreased immobility period in Fst and Tst, decreased latency escape in Mwm, reduced lipid peroxidation (lpo) and inflammatory cytokines, increased defensive enzymes, reduced acetylcholinesterase (AChE) activity and corrected histological lines. It is concluded that Rsp-instigated behavioral and memory deficits were prevented by Tq possibly via its strong antioxidant and anti-inflammatory effects.
